Guide to Subwoofer Calibration and Bass Preferences - Page 55 - AVS Forum | Home Theater Discussions And Reviews
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post #1621 of 1648 Old 11-19-2019, 07:39 PM
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Originally Posted by AmiraTech View Post
Well, it took me two weeks, but I managed to read the entire guide and all the thread posts. I can't even begin to express my gratitude to Mike and the numerous others who have contributed their time, knowledge, and experience to this thread. I wish it had existed ten years ago when I started work on my home theater. I'm also kicking myself for not checking the forum for the last few years until I decided to upgrade my single sub just last week.

I have never been quite happy with my home theater's audio performance despite a constant stream of upgrades over the years. Using the guide, I implemented several changes to my configuration and tweaked some speaker positions to arrive at an overall better sounding setup. While I consider the sound I have now to be good, I can't help but ask, can I make it better?

After many hours of experimentation, measuring and calibrating with Audyessy XT32, I can say definitively that the mobile app (in my case, on an iPad) produces superior results to the built-in calibration on my Denon AVR-X4300H. I encourage anyone with a supported receiver to give it a try.

I'm presently running a 7.2.4 Dolby Atmos setup in a rather large, open room/area on the lower level of our home. Speaker placement meets Dobly's guidelines for a 7.1.4 Hybrid Atmos system. My subs are the only speakers I can move without incurring any cost or breaking the Atmos speaker aliment.

As of last week, so well short of the 45-day return window, I am running dual SVS PC-2000 subs in the front corners of the room. In the front right corner, speaker size and placment limits mean my only real options are the PC-2000 or the PC-4000. In the front left corner, I have nearly no constraints. The room requires dual subs; single is not an option.

Attached is the MultiEq Room Correction Result. Calibration has my sub volume knobs near 10 o'clock, and AVR trim levels at -10.5. I have DEQ turned on and implemented cascading crossovers at 80Hz last night.

After pouring over the info on the SVS website, I realize I don't understand what I am looking at enough to grasp the potential benefits of using different subs in my environment. I'm hoping the collective wisdom of this group can provide some guidance.


Onto the questions at hand:
  1. Knowing that I won't use the onboard DSP, what are the potential benefits, if any, of two PC-4000s instead?
  2. With only the PC-2000 or PC-4000 as a front right option, what is the general guidance on using a different ported sub in the front left? Without restrictions, I could fit PB-16 Ultra if required.
In general, I'm looking to go lower and with more TR than I am experiencing now. The value does come into play here as I'd rather not increase my costs 3x for subtle gains.

All informed opinions are welcomed! Even those of you taking wild guesses will be thanked.
First, thank you for reading the whole Guide. Mike did put lots of work on it.

Cascading Crossover on the sub/s are great for in your chest mid-bass, but since you are also using DEQ. And still do not have enough TR, it let believe that your room is on a concrete floor. If so, due to nature of bass sound. Not much can be achieve for TR, since bass do not transmit well on concrete. But not all is loss, since you can always some TT for TR;
Shakers - Simple/Cheap Hookup - Visual Guide

If on a wooden structure, your problem is with locations.

Subs wise, I would go with dual PC4000. Since having two subs the same is a lot easier to integrated together. And also your calibration system, will go by the value of the lesser sub if using different ones. Meaning your superior sub, will be refrain to lesser sub.


Darth
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post #1622 of 1648 Old 11-19-2019, 08:15 PM
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Originally Posted by darthray View Post
First, thank you for reading the whole Guide. Mike did put lots of work on it.

Cascading Crossover on the sub/s are great for in your chest mid-bass, but since you are also using DEQ. And still do not have enough TR, it let believe that your room is on a concrete floor. If so, due to nature of bass sound. Not much can be achieve since bass do not transmit well on concrete. But not all is loss, since you can always some TT for TR;
Shakers - Simple/Cheap Hookup - Visual Guide

If on a wooden structure, your problem is with locations.

Subs wise, I would go with dual PC4000. Since having two subs the same is a lot easier to integrated together. And also your calibration system, will go by the value of the lesser sub if using different ones. Meaning your superior sub, will be refrain to lesser sub.
You are indeed correct, the room is the lower floor of a two story home, tile over concrete slab. I did consider some type of seat shakers in the past, but I’m worried about their effect on the life span of our power reclining sofas. Dual 4000s are such a significant price increase, I wonder how much they will really change the output in my room.

As you can see I’m not really pushing the 2000s that hard based on trim levels and volume knob locations. I don’t have any volume issues. SVS website specs don’t convince me the 4000 really goes any deeper. It looks like the 4000s add DSP and more SPL, which I’m not lacking due to the dual setup. I know I could always try and then return them, but still, it’s a lot of work.

Thanks for the input!
—Brian
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post #1623 of 1648 Old 11-19-2019, 08:19 PM
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Originally Posted by AmiraTech View Post
You are indeed correct, the room is the lower floor of a two story home, tile over concrete slab. I did consider some type of seat shakers in the past, but I’m worried about their effect on the life span of our power reclining sofas. Dual 4000s are such a significant price increase, I wonder how much they will really change the output in my room.

As you can see I’m not really pushing the 2000s that hard based on trim levels and volume knob locations. I don’t have any volume issues. SVS website specs don’t convince me the 4000 really goes any deeper. It looks like the 4000s add DSP and more SPL, which I’m not lacking due to the dual setup. I know I could always try and then return them, but still, it’s a lot of work.

Thanks for the input!
—Brian
Hi Brian,

Give it a few days, Mike is often on a business trip. And I am sure he will reply, for your best options


Darth
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post #1624 of 1648 Old 11-20-2019, 06:35 AM
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Originally Posted by AmiraTech View Post
You are indeed correct, the room is the lower floor of a two story home, tile over concrete slab. I did consider some type of seat shakers in the past, but I’m worried about their effect on the life span of our power reclining sofas. Dual 4000s are such a significant price increase, I wonder how much they will really change the output in my room.

As you can see I’m not really pushing the 2000s that hard based on trim levels and volume knob locations. I don’t have any volume issues. SVS website specs don’t convince me the 4000 really goes any deeper. It looks like the 4000s add DSP and more SPL, which I’m not lacking due to the dual setup. I know I could always try and then return them, but still, it’s a lot of work.

Thanks for the input!
—Brian
I was in your situation with my room,Great Bass with 2 Epik Empire Subs,but not as much TR as I wanted. My system is in my basement-Carpet over Tile over concrete floor-which almost Never is going to give you any Chest Pounding TR. The way I was able to get really good TR was to put 2 Behringer 1200D Subs behind my listening position/couch,I was very pleased! Than came my experimenting with Cascading Xover,When I finally got that right I had The Permanent Joker Smile on my face Ear to Ear! So if you haven't check out the thread on TR Midbass. Good luck it's doable. Look for the thread MBM Midbass ported subs tactical response, not sure if thats the exact name for the thread but its close.
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2 Channel: Magnepan 1.7i's,Proceed 2 Channel HPA Amp,Hovland HP100,Technics SP10MK2/SME/Benz....HT:126" Seymour AT Screen,JBL Studio 590's for LCR, Side and Rear Surrounds. Jbl SCS8'S for Fr Heights, and Rear Heights,2 Epik Empire Subs,2 Behringer B1200D Midbass Subs,Marantz 7702MK2,Proceed Amp-5,Outlaw 7125,Panasonic UB820 ,Toshiba HD35,JVC RS600. Black Velvet.

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post #1625 of 1648 Old 11-20-2019, 10:34 AM - Thread Starter
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Originally Posted by AmiraTech View Post
Well, it took me two weeks, but I managed to read the entire guide and all the thread posts. I can't even begin to express my gratitude to Mike and the numerous others who have contributed their time, knowledge, and experience to this thread. I wish it had existed ten years ago when I started work on my home theater. I'm also kicking myself for not checking the forum for the last few years until I decided to upgrade my single sub just last week.

I have never been quite happy with my home theater's audio performance despite a constant stream of upgrades over the years. Using the guide, I implemented several changes to my configuration and tweaked some speaker positions to arrive at an overall better sounding setup. While I consider the sound I have now to be good, I can't help but ask, can I make it better?

After many hours of experimentation, measuring and calibrating with Audyessy XT32, I can say definitively that the mobile app (in my case, on an iPad) produces superior results to the built-in calibration on my Denon AVR-X4300H. I encourage anyone with a supported receiver to give it a try.

I'm presently running a 7.2.4 Dolby Atmos setup in a rather large, open room/area on the lower level of our home. Speaker placement meets Dobly's guidelines for a 7.1.4 Hybrid Atmos system. My subs are the only speakers I can move without incurring any cost or breaking the Atmos speaker aliment.

As of last week, so well short of the 45-day return window, I am running dual SVS PC-2000 subs in the front corners of the room. In the front right corner, speaker size and placment limits mean my only real options are the PC-2000 or the PC-4000. In the front left corner, I have nearly no constraints. The room requires dual subs; single is not an option.

Attached is the MultiEq Room Correction Result. Calibration has my sub volume knobs near 10 o'clock, and AVR trim levels at -10.5. I have DEQ turned on and implemented cascading crossovers at 80Hz last night.

After pouring over the info on the SVS website, I realize I don't understand what I am looking at enough to grasp the potential benefits of using different subs in my environment. I'm hoping the collective wisdom of this group can provide some guidance.

Onto the questions at hand:
  1. Knowing that I won't use the onboard DSP, what are the potential benefits, if any, of two PC-4000s instead?
  2. With only the PC-2000 or PC-4000 as a front right option, what is the general guidance on using a different ported sub in the front left? Without restrictions, I could fit PB-16 Ultra if required.

In general, I'm looking to go lower and with more TR than I am experiencing now. The value does come into play here as I'd rather not increase my costs 3x for subtle gains.

All informed opinions are welcomed! Even those of you taking wild guesses will be thanked.
Quote:
Originally Posted by AmiraTech View Post
You are indeed correct, the room is the lower floor of a two story home, tile over concrete slab. I did consider some type of seat shakers in the past, but I’m worried about their effect on the life span of our power reclining sofas. Dual 4000s are such a significant price increase, I wonder how much they will really change the output in my room.

As you can see I’m not really pushing the 2000s that hard based on trim levels and volume knob locations. I don’t have any volume issues. SVS website specs don’t convince me the 4000 really goes any deeper. It looks like the 4000s add DSP and more SPL, which I’m not lacking due to the dual setup. I know I could always try and then return them, but still, it’s a lot of work.

Thanks for the input!
—Brian

Hi Brian,

First, you are very welcome for the Guide, and I'm glad that it has been so helpful! I am also pleased that you are enjoying using cascading crossovers. I do too! It is possible that you would enjoy your sound quality even more if you turned off DEQ. In that case, you would definitely want to increase the volume of your subwoofers to compensate for the reduction in bass that would occur. But, that would be very easy to do. As you noted, you aren't doing any post-calibration sub boosts.

Adding some independent sub boost, either with or without DEQ, would immediately add more of what you are looking for. You just might also get more audio clarity if you tried adding some subwoofer boost with DEQ off.

With respect to your specific question, upgrading to dual PC4000's will definitely give you more of the deep bass sounds and TR that you are looking for. As you observed, the PC4000's have more SPL across the board than the PC2000's do. But, where low-frequency bass sounds and sensations are concerned, the total SPL is not the most important thing. The most important factor for ported subs, particularly in a larger room where there isn't as much room gain to reinforce low-frequencies, is the subwoofers tuning point.

The PC2000 has a port tune of about 20Hz, and it's volume drops-off fairly fast below 20Hz. The PC4000 has a tuning point of 16Hz, in the Extended mode, and it carries much more SPL (and concomitant TR) into the upper teens and down into the low-teens. For most people, it is the frequencies below 20Hz that produce the most exciting deep bass special effects. The PC4000 not only has a lower port tune, it also has a larger cabinet volume, a more powerful amplifier, and more DSP directed into the <20Hz frequencies than the PC2000 has. Dual PC4000's would definitely be a significant upgrade to your dual PC2000's.

I agree with Darth, that it really wouldn't be worth your while to do one PC4000 and one PB16, equidistant from your listening position. If you could do dual PB16's, that would be another incremental upgrade. But, the upgrade from PC2000's to PC4000's will be a much more significant upgrade than the upgrade from dual PC4000's to dual PB16's would be. Since you need to stay with the cylinder shape for one of your subs, I would upgrade to dual PC4000's, if I were you. They will be easier to integrate from a FR standpoint, and it's a more cost-effective (and aesthetic) solution.

There is a lot of misunderstanding about TR (tactile response). For instance, skypop mentioned how much more he is enjoying his chest punch since he added his B1200D MBM's. Chest punch is a mid-bass phenomenon caused by sudden percussive sounds in the roughly 50Hz to 100Hz range. The air-filled cavities of our chests literally resonate momentarily, in response to those sudden percussive sounds, and to the pressure wave which accompanies them.

There is some evidence that the average person feels those chest punch sensations most strongly at a frequency of about 63Hz. Mid-bass modules, like his Behringer's, have port tunes of about 55Hz, and that's where they are concentrating their SPL and the pressure waves which accompany them. They can really increase mid-bass tactile sensations on any floor surface. Sounds which produce chest punch include sounds such as bass drum strikes and gunshots.

The deep bass sounds and TR that you are talking about occur at much lower frequencies than chest punch.They relate to deep rumbling and thudding sounds/sensations below about 30Hz, and especially below 20Hz. Concrete, laid on earth, doesn't transmit those deep bass vibrations as well as a suspended wood floor does. Someone wanting more of those low-bass sounds and sensations can really benefit from subs with a lower port tune and more power. With sufficient subwoofage, it is possible to achieve very respectable deep bass TR even in a large room, on concrete. Ask me how I know?

It is important to recognize that deep bass sounds and sensations require lower subwoofer capability and more subwoofer volume. We don't hear those frequencies as well as those closer to our normal hearing range. Subwoofers capable of playing those low-frequencies with sufficient SPL to be meaningful have to be larger (and more expensive) and they have to have lower tuning points.

In the short-term, I would turn-up the volume of your subs, on top of DEQ, when you want more deep bass SPL and TR. You could easily use your AVR trims to go up to about -5. In the longer-term, and within the 45-day period, I would upgrade to dual PC4000's. And, when you have them, I would experiment with turning DEQ off. You may get more clarity that way, as you did with cascading crossovers.

But remember that, either with or without DEQ, if you want to hear more bass (and especially more deep bass) you will need to use more of the inherent capability of your subwoofers, by increasing their volume. That is true with your PC2000's, and it will still be true with your new PC4000's. Audyssey's automated calibration makes your subwoofers play at the same volume as your other speakers. That is deliberate, for reasons explained in Section II of the Guide. But, we don't hear bass frequencies as well as we do the higher frequencies. If you want more bass, you will still need to turn-up the volume on your subwoofers in order to get it.

Incidentally, I think you may really enjoy some of the features on the PC4000's. As with the Audyssey Editor, we don't always know how valuable some features will be until we actually experiment with them. I hope this long post helps!

Regards,
Mike

GUIDE TO SUBWOOFER CALIBRATION AND BASS PREFERENCES

* The Guide linked above is a comprehensive guide to Audio & HT systems, including:
Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.
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post #1626 of 1648 Old 11-20-2019, 10:35 AM
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Quote:
Originally Posted by AmiraTech View Post
Well, it took me two weeks, but I managed to read the entire guide and all the thread posts. I can't even begin to express my gratitude to Mike and the numerous others who have contributed their time, knowledge, and experience to this thread. I wish it had existed ten years ago when I started work on my home theater. I'm also kicking myself for not checking the forum for the last few years until I decided to upgrade my single sub just last week.

I have never been quite happy with my home theater's audio performance despite a constant stream of upgrades over the years. Using the guide, I implemented several changes to my configuration and tweaked some speaker positions to arrive at an overall better sounding setup. While I consider the sound I have now to be good, I can't help but ask, can I make it better?

After many hours of experimentation, measuring and calibrating with Audyessy XT32, I can say definitively that the mobile app (in my case, on an iPad) produces superior results to the built-in calibration on my Denon AVR-X4300H. I encourage anyone with a supported receiver to give it a try.

I'm presently running a 7.2.4 Dolby Atmos setup in a rather large, open room/area on the lower level of our home. Speaker placement meets Dobly's guidelines for a 7.1.4 Hybrid Atmos system. My subs are the only speakers I can move without incurring any cost or breaking the Atmos speaker aliment.

As of last week, so well short of the 45-day return window, I am running dual SVS PC-2000 subs in the front corners of the room. In the front right corner, speaker size and placment limits mean my only real options are the PC-2000 or the PC-4000. In the front left corner, I have nearly no constraints. The room requires dual subs; single is not an option.

Attached is the MultiEq Room Correction Result. Calibration has my sub volume knobs near 10 o'clock, and AVR trim levels at -10.5. I have DEQ turned on and implemented cascading crossovers at 80Hz last night.

After pouring over the info on the SVS website, I realize I don't understand what I am looking at enough to grasp the potential benefits of using different subs in my environment. I'm hoping the collective wisdom of this group can provide some guidance.

Onto the questions at hand:
  1. Knowing that I won't use the onboard DSP, what are the potential benefits, if any, of two PC-4000s instead?
  2. With only the PC-2000 or PC-4000 as a front right option, what is the general guidance on using a different ported sub in the front left? Without restrictions, I could fit PB-16 Ultra if required.

In general, I'm looking to go lower and with more TR than I am experiencing now. The value does come into play here as I'd rather not increase my costs 3x for subtle gains.

All informed opinions are welcomed! Even those of you taking wild guesses will be thanked.
How large is "rather large"? Include all cubic footage the sub can "see", please.

Audyssey set both sub trims at exactly -10.5? Have you tried boosting the sub trim at all post-Audyssey? As you know from reading the guide, a post-Audyssey boost to the sub trim of 3-6dB is quite common.

Are both subs close to equidistant to the MLP? If so, you may have even better results by using a single sub out from the AVR with a y-splitter.

I would not be afraid of using TR devices with motorized seating, but the guys in this thread would know for sure.

Your "Before" Audyssey graph shows a large dip centered at 45hz. The dip spans two octaves and ranges from -10dB to -12dB. Even if Audyssey was actually able to boost this dip up to flat, that amount of EQ boost will likely result in "muddy" and/or "boomy" bass over those octaves. I would try as hard as I could to re-position the subs to try and get a flatter pre-Audyssey graph. Even rotating a sub 90 or 180 degrees or just moving it just a few inches can make a difference.
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post #1627 of 1648 Old 11-20-2019, 03:25 PM
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Originally Posted by mthomas47 View Post
Hi Brian,

First, you are very welcome for the Guide, and I'm glad that it has been so helpful! I am also pleased that you are enjoying using cascading crossovers. I do too! It is possible that you would enjoy your sound quality even more if you turned off DEQ. In that case, you would definitely want to increase the volume of your subwoofers to compensate for the reduction in bass that would occur. But, that would be very easy to do. As you noted, you aren't doing any post-calibration sub boosts.

Adding some independent sub boost, either with or without DEQ, would immediately add more of what you are looking for. You just might also get more audio clarity if you tried adding some subwoofer boost with DEQ off.

With respect to your specific question, upgrading to dual PC4000's will definitely give you more of the deep bass sounds and TR that you are looking for. As you observed, the PC4000's have more SPL across the board than the PC2000's do. But, where low-frequency bass sounds and sensations are concerned, the total SPL is not the most important thing. The most important factor for ported subs, particularly in a larger room where there isn't as much room gain to reinforce low-frequencies, is the subwoofers tuning point.

The PC2000 has a port tune of about 20Hz, and it's volume drops-off fairly fast below 20Hz. The PC4000 has a tuning point of 16Hz, in the Extended mode, and it carries much more SPL (and concomitant TR) into the upper teens and down into the low-teens. For most people, it is the frequencies below 20Hz that produce the most exciting deep bass special effects. The PC4000 not only has a lower port tune, it also has a larger cabinet volume, a more powerful amplifier, and more DSP directed into the <20Hz frequencies than the PC2000 has. Dual PC4000's would definitely be a significant upgrade to your dual PC2000's.

I agree with Darth, that it really wouldn't be worth your while to do one PC4000 and one PB16, equidistant from your listening position. If you could do dual PB16's, that would be another incremental upgrade. But, the upgrade from PC2000's to PC4000's will be a much more significant upgrade than the upgrade from dual PC4000's to dual PB16's would be. Since you need to stay with the cylinder shape for one of your subs, I would upgrade to dual PC4000's, if I were you. They will be easier to integrate from a FR standpoint, and it's a more cost-effective (and aesthetic) solution.

There is a lot of misunderstanding about TR (tactile response). For instance, skypop mentioned how much more he is enjoying his chest punch since he added his B1200D MBM's. Chest punch is a mid-bass phenomenon caused by sudden percussive sounds in the roughly 50Hz to 100Hz range. The air-filled cavities of our chests literally resonate momentarily, in response to those sudden percussive sounds, and to the pressure wave which accompanies them.

There is some evidence that the average person feels those chest punch sensations most strongly at a frequency of about 63Hz. Mid-bass modules, like his Behringer's, have port tunes of about 55Hz, and that's where they are concentrating their SPL and the pressure waves which accompany them. They can really increase mid-bass tactile sensations on any floor surface. Sounds which produce chest punch include sounds such as bass drum strikes and gunshots.

The deep bass sounds and TR that you are talking about occur at much lower frequencies than chest punch.They relate to deep rumbling and thudding sounds/sensations below about 30Hz, and especially below 20Hz. Concrete, laid on earth, doesn't transmit those deep bass vibrations as well as a suspended wood floor does. Someone wanting more of those low-bass sounds and sensations can really benefit from subs with a lower port tune and more power. With sufficient subwoofage, it is possible to achieve very respectable deep bass TR even in a large room, on concrete. Ask me how I know?

It is important to recognize that deep bass sounds and sensations require lower subwoofer capability and more subwoofer volume. We don't hear those frequencies as well as those closer to our normal hearing range. Subwoofers capable of playing those low-frequencies with sufficient SPL to be meaningful have to be larger (and more expensive) and they have to have lower tuning points.

In the short-term, I would turn-up the volume of your subs, on top of DEQ, when you want more deep bass SPL and TR. You could easily use your AVR trims to go up to about -5. In the longer-term, and within the 45-day period, I would upgrade to dual PC4000's. And, when you have them, I would experiment with turning DEQ off. You may get more clarity that way, as you did with cascading crossovers.

But remember that, either with or without DEQ, if you want to hear more bass (and especially more deep bass) you will need to use more of the inherent capability of your subwoofers, by increasing their volume. That is true with your PC2000's, and it will still be true with your new PC4000's. Audyssey's automated calibration makes your subwoofers play at the same volume as your other speakers. That is deliberate, for reasons explained in Section II of the Guide. But, we don't hear bass frequencies as well as we do the higher frequencies. If you want more bass, you will still need to turn-up the volume on your subwoofers in order to get it.

Incidentally, I think you may really enjoy some of the features on the PC4000's. As with the Audyssey Editor, we don't always know how valuable some features will be until we actually experiment with them. I hope this long post helps!

Regards,
Mike
Quote:
Originally Posted by Alan P View Post
How large is "rather large"? Include all cubic footage the sub can "see", please.

Audyssey set both sub trims at exactly -10.5? Have you tried boosting the sub trim at all post-Audyssey? As you know from reading the guide, a post-Audyssey boost to the sub trim of 3-6dB is quite common.

Are both subs close to equidistant to the MLP? If so, you may have even better results by using a single sub out from the AVR with a y-splitter.

I would not be afraid of using TR devices with motorized seating, but the guys in this thread would know for sure.

Your "Before" Audyssey graph shows a large dip centered at 45hz. The dip spans two octaves and ranges from -10dB to -12dB. Even if Audyssey was actually able to boost this dip up to flat, that amount of EQ boost will likely result in "muddy" and/or "boomy" bass over those octaves. I would try as hard as I could to re-position the subs to try and get a flatter pre-Audyssey graph. Even rotating a sub 90 or 180 degrees or just moving it just a few inches can make a difference.
Bear with me here as I likely fumble my way through some the terminology and articulating what I mean into correct terms. I'll walk through both your replies in order...

DEQ: I find that I do prefer it turned on and require no post-calibration boost to the sub channel when using the MultEQ app. When using the AVR's built-in Audyessy, a sub channel boost was needed. The way DEQ handles the increase relative to the volume setting appears to be the winner in my setup. Everything sounds better across all volume levels. I'd estimate 90% or our use is -30 to -15 daily, and movie nights can hit -10.

With DEQ off, an additional sub boost is needed, but the overall effect on the sound is not the same or as even as DEQ. While it does boot the low bass coming from the sub, it sounds like other frequencies (mid-bass or mid-range?) have fallen off the charts. At our normal listing levels, the entire front sound stage is very shallow without much dynamic range, like the mid and low frequencies have been removed.

It seems the info I was missing on the SVS site is the port tuning specifications of the subs. Even looking at the site now, I'm still not sure where you got some of this info from, though I absolutely trust it.

Upon reading the replies about TR, I believe your interpretation of what I am looking for is the correct one. I thank both you and skypop for your replies, without which I would not have known the difference and been able to understand which I am after.

I'm inclined to believe that a sub(s) with a lower port tune is what I am after at this point. Turning up the volume/trim on the subs makes everything louder but not much, if any, lower to my ears. Everything gets louder while I attempt to hear something which I feel is missing, and other frequencies I think are just fine become too dominating.

The size of the room is a little tricky to explain, so here are some photos which were taken 10 years ago when we did a pre-purchase walkthrough. Though we have entirely gutted and remodeled, the shape of the rooms remains the same as we did not tear down walls. My TV and sofas are in the same general locations as in these photos. The only significate structural change would be that we removed the 1-foot drop ceiling in the kitchen, raising it to the same hight as the rest of the lower level.

Ceilings are 8 feet high. The wall the TV is on is approximately 17 feet wide but opens up to be much wider once you reach the wet bar, which starts about 4 feet off the TV wall. The distance from the TV wall to the pony wall of the kitchen counter is 19 feet. This "rear wall" area of the theater area actually contains minimal wall obviously.

Both subs are not equidistant to the MLP. I would estimate the front left sub is about 1 to 2 feet farther to the left. I have the freedom to move the right sub forward and back a few inches but no space to the left or right. It is nearly up against the sliding glass door as it is, and my front tower sits next to it. The left sub has at least a foot of mobility in every direction, and more once I move off the TV wall.

I did notice the dip at 45hz and was surprised, given the dual sub setup. What I plan to try next is to do an Auddysey EQ run for just the subs but do them individually to see how their placement is impacting their own FR. Who knows, maybe I can make 1 sub work, in which case I would just go with something massive in the left corner. I know dual is better and provides a more even distribution amongst multiple listening positions. I did have very uneven bass across the seats on our main sofa, which is why I went dual. Honestly, I never bothered to try to solve the problem by moving and tweaking my existing sub as I wanted something better anyways.

An interesting note on sub rotation, don't forget these are cylinder towers. Ed Mullen from SVS stated the orientation of the sub and the direction the port is facing makes no difference at all to the FR of this model. He specifically said you could face the controls (and port) outward while EQ'ing for ease of access and then rotate the port and controls to the rear when done with no impact to calibration. This was in another thread I found on AVS while researching the PC-2000 and 4000 subs.

So to recap, I want to see if I can figure out the 45hz dip, and I'm interested in trying a single sub before moving to dual PS-4000s, because I have not yet won the lottery!

Best Regards!
--Brian
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Keep in mind, just having dual subs is not a guarantee of smooth response. Plopping two subs down into a room without optimizing their placement and interaction with each other will not guarantee you a flatter response.

To me, it sounds like your next step should be the purchase of a UMIK-1.
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Keep in mind, just having dual subs is not a guarantee of smooth response. Plopping two subs down into a room without optimizing their placement and interaction with each other will not guarantee you a flatter response.

To me, it sounds like your next step should be the purchase of a UMIK-1.
My wife already thought I was nuts when I spent weeks learning how to calibrate the TV, and buying all the equipment that went along with the job. She is going to love you for this one! I just need to explain to her how Audyssey is not good enough. Had never heard of REW before this thread, but just ordered the mic and plan to spend my weekend once again ignoring the family.

I've been a video snob for decades, but only recently decided to apply a similar level of dedication to audio.

Thanks,
--Brian
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My wife already though I was nuts when I spent weeks learning how to calibrate the TV, and buying all the equipment that went along with the job. She is going to love you for this one! I just need to explain to her how Audyssey is not good enough. Had never head of REW before this thread, but just ordered the mic and plan to spend my weekend once again ignoring the family.

I've been a video snob for decades, but only recently decided to apply a similar level of dedication to audio.

Thanks,
--Brian
Glad to hear it! In that case, you may find this video quite useful and informative.


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I never really looked at the Audyssey graphs, but after reading so much about REW I eventually took the plunge and bought a mic and a cheap laptop. Even with 3 subs, I had a pretty substantial hump at 40 Hz that was drowning out the lower bass.
Even after getting each to measure good on their own, they didn't measure as good together. Rotating 2 of them 90 degrees made them all play together better. Now my bass is pretty flat down below 20 Hz. REW can be a pain to set up initially, but the results were well worth it to me.
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post #1632 of 1648 Old 11-21-2019, 01:51 PM
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So after a bit more sub research, a bunch more reading, and a plan to spend this weekend with REW, I think I've got my options narrowed down to the following:
  1. Keep the dual PC-2000s and improve performance via REW, if possible, given my sub placement options.
  2. Move to a single PB-4000, REW and onboard DSP optimized.
  3. Go dual PC-4000, optimize as best I can and then be happy until I convert a different room into a dedicated theater.

Since those are basically in order of cost, I'd also consider that my order of preference. I'm going to watch the REW training video today, but if anyone has any tips or pointers they would like to share as I dive into all this to optimize my subs, please do so. Also appreciate any thoughts on the 3 options above. Despite reading the guide section on sub selection multiple times, I'm still struggling a bit with comparing subs based on the graphs and tech specs SVS publishes. While I understand frequency range, once you add all the other stats in and try to compare the subs on paper I get a little fuzzy.

Thanks again!

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^^^

For the REW basics like installing the software and getting it up and running, make sure to use AustinJerry's guide which is linked in my sig.
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Originally Posted by AmiraTech View Post
So after a bit more sub research, a bunch more reading, and a plan to spend this weekend with REW, I think I've got my options narrowed down to the following:
  1. Keep the dual PC-2000s and improve performance via REW, if possible, given my sub placement options.
  2. Move to a single PB-4000, REW and onboard DSP optimized.
  3. Go dual PC-4000, optimize as best I can and then be happy until I convert a different room into a dedicated theater.

Since those are basically in order of cost, I'd also consider that my order of preference. I'm going to watch the REW training video today, but if anyone has any tips or pointers they would like to share as I dive into all this to optimize my subs, please do so. Also appreciate any thoughts on the 3 options above. Despite reading the guide section on sub selection multiple times, I'm still struggling a bit with comparing subs based on the graphs and tech specs SVS publishes. While I understand frequency range, once you add all the other stats in and try to compare the subs on paper I get a little fuzzy.

Thanks again!

Hi,

Alan has been giving you great advice on ways to improve your current subwoofer performance. Once you have REW up and running, you will have a lot more information. For instance, if you want to have a good idea how a single PB4000 will perform on the more flexible side of your room, just move the comparable PC2000 out about a foot from the wall (to account for the box cabinet design) and measure that single subwoofer with REW. You can try to optimize the performance of that single subwoofer somewhat with REW, whether it is a PC2000 or a PB4000. That will give you a good indication of whether a single sub, in that position, will work well for you.

Earlier, you said that when you turned-up the volume on your PC2000's, they got louder everywhere, and not just in the lower frequencies where you really wanted to hear and feel more low-bass. It's possible that you will see something in the frequency response of the two PC2000's that will help with that. For instance, you may be getting some cancellation below 30Hz, and if so, it will show-up on a graph of the frequency response. You can post for advice about interpreting those graphs either here or on Jerry's thread. I would consider Jerry's thread the best place to post, but we can help you here, too.

It is equally (actually more) likely that you are just running into the inherent limitation of the PC2000's. As noted earlier, the port tune on the PC4000's (in Extended mode) is at least 4 or 5Hz lower than is the case for the PC2000's. That's a lot of difference, where the low-frequency sound effects in movies (and many TV shows) are concerned. And, the PC4000 continues to carry SPL out much further than the PC2000 does.

You don't really have to compare numbers between the two subs. There is an easier way to compare low-frequency performance in subs, and that's to look at the natural shape of their frequency responses. If you want to see this represented graphically, look at the PC2000 page on the SVS website. Click on "Tech Info". Don't worry about the SPL, just look at the outdoor (quasi-anechoic) performance as represented by the purple line. Do you see how relatively flat the line is, out to about 24 or 25Hz, and then how quickly it drops off? The PC2000 will roll-off a little below that frequency indoors, but dual PC2000's will both still start to roll-off much earlier than a PC4000 will.

Now, pull-up the SVS page for the PC4000, click on "Tech Info" and compare that graph to the PC2000 graph. Do you see how the green line (Extended mode) stays flat out to about 18Hz, and only then begins to roll-off? That's about a 6-7Hz difference between the two subs. And, just like the PC2000, the PC4000 will do better indoors than it does outdoors. Consequently a PC4000 will produce much more <25Hz SPL, compared to a PC2000. And, it's those low-frequencies that we really want for the special effects in movies, and that you say you are missing now.

I think that you will be able to use REW to determine whether you need dual subs or not, as described in the first paragraph. Most people who can implement dual subs properly do benefit from having them. It's not just the improved frequency response, it is also the additional 6db of SPL, and the improved bass envelopment that typically results from having more than one sub. Particularly, if you are already used to multiple bass sources.

But, you can test the envelopment idea by running only one PC2000 for a while, right where the potential PB4000 would be. You aren't listening for deeper bass, you are just trying to determine whether you can localize the sub sounds/sensations as coming from one side of the room or not. If you can, it is likely that will only intensify as you added a more powerful subwoofer with lower extension. My guess is that long-term you are still going to want dual subs, but you could always take it slowly and just buy one at a time.

I think you already know that you won't want to mix a 2000 with a 4000, but you can certainly mix a PB4000 with a PC4000 if you prefer starting with a box sub, rather than a cylinder sub, on the more flexible side of the room. There is no performance difference between the PB4000 and the PC4000, so you can always order a PB4000 to find out how well it works, and then order a PC4000, for the other position, later if you want to.

It all starts, though, with your own investigations into the use of REW. Wherever you decide to post for advice, let us know how your investigations into one PC2000, versus dual PC2000's work out. That will tell you a lot about whether you will eventually want one 4000, or duals. And, if everything works out perfectly, perhaps you can stay with your Option 1.

Regards,
Mike
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Quote:
Originally Posted by Spidacat View Post
I never really looked at the Audyssey graphs, but after reading so much about REW I eventually took the plunge and bought a mic and a cheap laptop. Even with 3 subs, I had a pretty substantial hump at 40 Hz that was drowning out the lower bass.
Even after getting each to measure good on their own, they didn't measure as good together. Rotating 2 of them 90 degrees made them all play together better. Now my bass is pretty flat down below 20 Hz. REW can be a pain to set up initially, but the results were well worth it to me.
Glad to see, REW did work well for you
And got to mention, I love your Avatar!!! What a nice pair of kittens, a black one and the other white.
Members who know me, do know that I am a Cat Lover.

Now that you have your bass sound cover, all is left. Is enjoy or tweak the mains and surrounds, if needed


Darth
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post #1636 of 1648 Old 11-22-2019, 04:24 PM
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Glad to see, REW did work well for you
And got to mention, I love your Avatar!!! What a nice pair of kittens, a black one and the other white.
Members who know me, do know that I am a Cat Lover.

Now that you have your bass sound cover, all is left. Is enjoy or tweak the mains and surrounds, if needed


Darth
I mostly added that as a follow up to Alan's advice that even with multiple subs you may not have a good frequency response. I haven't tweaked my current set up much beyond that and the subwoofer distance tweak since I'm planning on upgrading from front stage soon. After that I'll go whole hog with REW again. Hopefully I can get it going again since there have been multiple updates to both REW and Windows.

Even non cat lovers seem to like the "yin yang" duo. My wife adopted the white one from a cat breeder who also finds homes for litters that would have gone to the animal shelter. I've always had and will always have a black cat in my life. My Mom got a black kitten before I was born. Cat lived to 19. I could drive, vote, be drafted... and the cat was still older than me! Ever since then I've had an attachment for black cats.
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post #1637 of 1648 Old 11-25-2019, 01:41 AM
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I spent some time with REW today and would appreciate any input on my interpretations of the attached graphs. I also include the REW data file for anyone who would like to take a closer look. As always, I appreciate corrections on any points which I misunderstood or misinterpreted.

A couple of details to keep in mind which I believe to be important for correct analysis of these results:
  1. Audyssey was turned off for all tests
  2. AVR Trim levels and sub gain knobs were NOT adjusted from Audyssey settings
  3. Sub crossovers were set back to max LFE setting
  4. AVR LFE setting was put back to 120
  5. MLP = Main Listening Position, LLP = Left, RLP = Right

When I was switching between the single and dual subwoofer tests, I made no gain or trim adjustments to compensate for the lower total SPL, which are expected from a single sub. Given that both my subs have the gain knobs at close to 10 o'clock and my AVR trims are set to -10.5 for both, I think I have enough headroom where a single sub could provide adequate SPL. I have been trying to achieve a smoother frequency response across multiple listening positions using multiple subs, and I was not focused on increased output.

As a reminder, I have two SVS PC-2000 cylindrical subs. I did confirm that in my environment, and within the constraints of my placements options, moving them around had no impact on frequency response. Rotating the subs and changing the direction the port is facing also did not affect their FR.

My interpretations of the graphs are that the dual subs are providing a more consistent FR across the three listening positions. Something in my room causes a drop in the 40-50hz range regardless of sub position. The dual subs seem to make the drop a bit stronger but narrower across the frequency range. I did do a REW measurement with Audyssey enabled, but I forgot to save it. Audyssey EQ corrections do a decent job of smoothing out the FR of the dual subs. It's nowhere near flat, but certainly better than without Audyssey.

All of the above makes me think that I should stick with dual subs. Given that the right sub location can only support a PC-2000 or PC-4000, it makes the most sense to get a matching unit for the left sub. That means to keep what I have now, upgrade to 2x 4000s right now, or go with 1x 4000 now and add the additional 4000 later.

The only unknown factor in this setup is how a single box sub would perform. If I went with a single PB-4000 in the left location, would its design be influenced by the changes in position or rotation that didn't affect the cylindrical subs? I wonder what the likelihood is of achieving a more even FR across the 3 listening positions with a single PB vs. single PC.

Thanks again for your input.
--Brian
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post #1638 of 1648 Old 11-26-2019, 07:59 AM - Thread Starter
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Quote:
Originally Posted by AmiraTech View Post
I spent some time with REW today and would appreciate any input on my interpretations of the attached graphs. I also include the REW data file for anyone who would like to take a closer look. As always, I appreciate corrections on any points which I misunderstood or misinterpreted.

A couple of details to keep in mind which I believe to be important for correct analysis of these results:
  1. Audyssey was turned off for all tests
  2. AVR Trim levels and sub gain knobs were NOT adjusted from Audyssey settings
  3. Sub crossovers were set back to max LFE setting
  4. AVR LFE setting was put back to 120
  5. MLP = Main Listening Position, LLP = Left, RLP = Right

When I was switching between the single and dual subwoofer tests, I made no gain or trim adjustments to compensate for the lower total SPL, which are expected from a single sub. Given that both my subs have the gain knobs at close to 10 o'clock and my AVR trims are set to -10.5 for both, I think I have enough headroom where a single sub could provide adequate SPL. I have been trying to achieve a smoother frequency response across multiple listening positions using multiple subs, and I was not focused on increased output.

As a reminder, I have two SVS PC-2000 cylindrical subs. I did confirm that in my environment, and within the constraints of my placements options, moving them around had no impact on frequency response. Rotating the subs and changing the direction the port is facing also did not affect their FR.

My interpretations of the graphs are that the dual subs are providing a more consistent FR across the three listening positions. Something in my room causes a drop in the 40-50hz range regardless of sub position. The dual subs seem to make the drop a bit stronger but narrower across the frequency range. I did do a REW measurement with Audyssey enabled, but I forgot to save it. Audyssey EQ corrections do a decent job of smoothing out the FR of the dual subs. It's nowhere near flat, but certainly better than without Audyssey.

All of the above makes me think that I should stick with dual subs. Given that the right sub location can only support a PC-2000 or PC-4000, it makes the most sense to get a matching unit for the left sub. That means to keep what I have now, upgrade to 2x 4000s right now, or go with 1x 4000 now and add the additional 4000 later.

The only unknown factor in this setup is how a single box sub would perform. If I went with a single PB-4000 in the left location, would its design be influenced by the changes in position or rotation that didn't affect the cylindrical subs? I wonder what the likelihood is of achieving a more even FR across the 3 listening positions with a single PB vs. single PC.

Thanks again for your input.
--Brian

Hi Brian,

Here is what I see from your graphs. Considering only the MLP for a moment, on the assumption that it is the most important listening position, there is a consistent area of cancellation between about 40 and 60Hz, regardless of which subwoofer is playing or whether both subs are playing. That makes me think that your sofa position may be the culprit. And, this is important, because you are losing a lot of bass content with such a deep dip across such a wide portion of the bass frequency range.

It is difficult to tell precisely from your photos, but it looks as if you may be sitting at about the mid-point of the room length. If so, you are sitting in a null, and that's why you have such a wide and deep dip between 40 and 60Hz. The solution to that would be to move your sofa back by a foot or two.

Just as with moving subs a little bit, sometimes even a few inches can make a difference. I would experiment with sliding your sofa back a little and remeasure. Try moving it 6", which would be visually imperceptible, and then try moving it back a foot if necessary. Does the dip improve with either of the subs? You can experiment in an effort to just get rid of that large dip, and you can concentrate most of your measurements around the MLP. Most people would take a half-dozen measurements around the area where your head would be (corresponding to the binaural nature of our hearing) and then let REW average the results.

Once you get a pretty decent frequency response at your MLP, you can spend additional time trying to optimize the frequency response for the other listening positions as well. And, that's where you will be able to tell more about having one sub versus two. But, you are the one who is most concerned about good sound quality, and who is investing in your audio components, and in REW, in order to get it. If you don't obtain a good frequency response and concomitant sound quality for at least the MLP, I don't think that you will ever be satisfied. So, I would recommend starting there.

Regards,
Mike
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Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.
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post #1639 of 1648 Old 12-01-2019, 05:05 PM - Thread Starter
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Lightbulb Guide Edit

I make edits to the Guide on a fairly regular basis, whenever I understand something a little better or believe that I can explain something a little better. So, it remains a work in progress and I rarely call attention to my edits.

But, a post today on the PSA subwoofer thread, confirming the use of Cascading Crossovers as a way to use a significant subwoofer boost, while keeping the bass above 80Hz from sounding so heavy, inspired me to add some more detail to the article on Cascading Crossovers in Section III-C.

Here is the new material which I added today, and I think it helps to explain why Cascading Crossovers worked so well for that particular individual:


"* I decided to add a little more detail to this idea of rolling-off subs a little faster, above 80Hz, especially where significant subwoofer boosts are employed. Let's look at the LFE channel first and assume an LPF setting of 120Hz. For the 8-note octave between 120Hz and 240Hz, the low-pass filter will roll-off the subs by 24db. That sounds like a lot, but what that means in practical terms is that the subwoofer will lose -4db of volume at 140Hz, -8db at 160Hz, and so on up to -24db at 240Hz.

Now, let's assume that someone wants to use a fairly significant subwoofer boost. An 8db boost using something such as DEQ, or through independent subwoofer boosts, would not be at all uncommon. Instead of being down by 8db at 160Hz, the subwoofer would still be playing that frequency at the same volume level that it would have been playing, if there hadn't been a boost. And, the LFE channel is already playing 10db hotter than the regular channels.

It is easy to see that the subwoofer boost, occurring above 120Hz could make the bass in the LFE channel sound a little heavy. It is also easy to see how that boost above 120Hz could make the subwoofers strain a little more, depending on the overall listening/subwoofer volume. Very few subwoofers can play as clearly, with as little strain or compression, at 160Hz as they can at 120Hz. Rolling-off the LFE channel, above 80Hz, can help to alleviate that potential issue.

The same thing happens in the regular channels, but starting at a lower frequency, if an 80Hz crossover is being employed. Just a 6db boost (which is very modest for some people) would make the 100Hz frequency play as loudly as the 80Hz frequency would have played without the boost. Again, it is easy to imagine that the extra boost for the center channel (above 80Hz) could make some male voices sound a little more chesty, as bass fundamentals were amplified. And, that in-turn, could make dialogue sound a little thicker and a little less intelligible. Again, rolling-off the subs a little faster, above the crossover, helps to alleviate that issue where it is an audible problem."


There is also a more detailed explanation, further down in that section, for why dialogue intelligibility might be compromised with bass boosts above 80Hz. I think it is particularly noticeable with some male voices. And, let's face it, with ambient audio effects in the background, and some actors not enunciating as clearly as they might, we sometimes need all the help we can get.

Belated Happy Thanksgiving!

Regards,
Mike
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* The Guide linked above is a comprehensive guide to Audio & HT systems, including:
Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.

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post #1640 of 1648 Old 12-02-2019, 07:54 AM
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Any advise would be welcome.

I have one sub only (small room and waf factors!).


For movies with a 5.1 system, seeing the graph joined, which place would you suggest?
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My system 5.1 :ROTEL RSX-1562 /Fronts: B & W 804 D2; surround : B&W 704 and center B&W HTM4d2 /sub SVS PC 2000 / TV Samsung UN55ES8000
/BD player Cambridge CXU/ set-top (cable box) rented from cable co. PEQ by nanoAvr-DL Dirac Live between CXU and receiver
Bis Audio cables and power bar from the wall to the receiver
My room:15'4" x 11' 6" x 7'6" tv near the center of the long side wall

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post #1641 of 1648 Old 12-02-2019, 08:22 AM
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Any advise would be welcome.

I have one sub only (small room and waf factors!).


For movies with a 5.1 system, seeing the graph joined, which place would you suggest?
Depends on “your” personal bass preference...blue (low bass - rumble) or green (mid bass - more tactile - gun shots). If possible, you may still want to experiment with position a bit more to find a location that will result in the best of both worlds.
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post #1642 of 1648 Old 12-02-2019, 08:48 AM - Thread Starter
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Any advise would be welcome.

I have one sub only (small room and waf factors!).


For movies with a 5.1 system, seeing the graph joined, which place would you suggest?

Hi,

Ideally, as Gene suggested, you would be able to find another location that might work even better. For instance, you might consider putting the subwoofer very close to your main listening position.

But, if those two locations are your best (or only) choices, then I would go with the Blue position. You have a nice rising low-bass curve with that location. As Gene noted, your main problem is the null between about 58 and 70Hz. That is right in prime chest punch territory.

You might, however, be able to reduce the size of that null by experimenting with the phase control on your subwoofer. You can make small adjustments to the phase control (exiting from your AVR menu each time) and measuring to see whether the null reduces in size, or moves upward in frequency. If it moves up to 80Hz or higher, it should be less noticeable than having it between 60 and 70Hz.

Let us know if this helps at all.

Regards,
Mike
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GUIDE TO SUBWOOFER CALIBRATION AND BASS PREFERENCES

* The Guide linked above is a comprehensive guide to Audio & HT systems, including:
Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.
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post #1643 of 1648 Old 12-02-2019, 03:19 PM
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Thank Gene and Thomas. Green second choice is the sub close to my right hand at mlp, but maybe not faisable. I will report soon on experiment with phase.
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My system 5.1 :ROTEL RSX-1562 /Fronts: B & W 804 D2; surround : B&W 704 and center B&W HTM4d2 /sub SVS PC 2000 / TV Samsung UN55ES8000
/BD player Cambridge CXU/ set-top (cable box) rented from cable co. PEQ by nanoAvr-DL Dirac Live between CXU and receiver
Bis Audio cables and power bar from the wall to the receiver
My room:15'4" x 11' 6" x 7'6" tv near the center of the long side wall
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post #1644 of 1648 Old 12-02-2019, 07:25 PM
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Hi Brian,

Here is what I see from your graphs. Considering only the MLP for a moment, on the assumption that it is the most important listening position, there is a consistent area of cancellation between about 40 and 60Hz, regardless of which subwoofer is playing or whether both subs are playing. That makes me think that your sofa position may be the culprit. And, this is important, because you are losing a lot of bass content with such a deep dip across such a wide portion of the bass frequency range.

It is difficult to tell precisely from your photos, but it looks as if you may be sitting at about the mid-point of the room length. If so, you are sitting in a null, and that's why you have such a wide and deep dip between 40 and 60Hz. The solution to that would be to move your sofa back by a foot or two.

Just as with moving subs a little bit, sometimes even a few inches can make a difference. I would experiment with sliding your sofa back a little and remeasure. Try moving it 6", which would be visually imperceptible, and then try moving it back a foot if necessary. Does the dip improve with either of the subs? You can experiment in an effort to just get rid of that large dip, and you can concentrate most of your measurements around the MLP. Most people would take a half-dozen measurements around the area where your head would be (corresponding to the binaural nature of our hearing) and then let REW average the results.

Once you get a pretty decent frequency response at your MLP, you can spend additional time trying to optimize the frequency response for the other listening positions as well. And, that's where you will be able to tell more about having one sub versus two. But, you are the one who is most concerned about good sound quality, and who is investing in your audio components, and in REW, in order to get it. If you don't obtain a good frequency response and concomitant sound quality for at least the MLP, I don't think that you will ever be satisfied. So, I would recommend starting there.

Regards,
Mike
With Thanksgiving behind us here in the USA, it's time for me to do some catchup on this. The photos of the room are a little deceiving as my seating position is not in the midpoint of the room in either length or width. I'd estimate the LLP is 14 feet from the TV wall and only 5 behind it to the kitchen counter. The MLP is a bit after the kitchen counter starts to curve and the RLP is nearly clear of the kitchen wall entirely, more in line with the opening into the room beyond the kitchen.

I did spend some more time with REW and moving both the sofa and speakers around. I'm really shocked that everything I did had no significant impact on that 40-60hz dip. I moved the subs around well beyond what would be aesthetically acceptable, by several feet in multiple directions on the left and well off the wall on the right. I also moved the sofa back more than a foot. Nothing had much impact on the FR. It seems like I'm stuck with the acoustics of this room as is and my only option is to EQ out that dip.

I figured out that if I bring my front L+R towers in just about 1 inch, I can fit a PB-3000 in both locations, which is a less expensive option than a dual PC-4000 setup, so I'm going to try that first. The FR graphs and info on the SVS website don't make it seem like there is much of a difference between the PC-2000 and PB-3000 beyond total SPL, which had me a bit stumped as how to proceed.

I did some more research and came across comparative reviews of the subs which stated the specs/graphs don't tell the whole story, and while they look the same on paper they sound noticeably different in person. I'm sure most experts here already knew this, but for me it was nice to find it explained in non-technical terms. I'm really trying to avoiding buying 3 different sets of subs and returning 2 of them before I find what I like, but it looks like I might have no other choice.

With lots of free time over the next few weeks, I'm sure I'll have updates to report back on my findings.

Thanks again for all the help, and the additional info on cascading crossovers in the guide!
--Brian
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post #1645 of 1648 Old 12-03-2019, 07:55 AM
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I make edits to the Guide on a fairly regular basis, whenever I understand something a little better or believe that I can explain something a little better. So, it remains a work in progress and I rarely call attention to my edits.

But, a post today on the PSA subwoofer thread, confirming the use of Cascading Crossovers as a way to use a significant subwoofer boost, while keeping the bass above 80Hz from sounding so heavy, inspired me to add some more detail to the article on Cascading Crossovers in Section III-C.

Here is the new material which I added today, and I think it helps to explain why Cascading Crossovers worked so well for that particular individual:


"* I decided to add a little more detail to this idea of rolling-off subs a little faster, above 80Hz, especially where significant subwoofer boosts are employed. Let's look at the LFE channel first and assume an LPF setting of 120Hz. For the 8-note octave between 120Hz and 240Hz, the low-pass filter will roll-off the subs by 24db. That sounds like a lot, but what that means in practical terms is that the subwoofer will lose -4db of volume at 140Hz, -8db at 160Hz, and so on up to -24db at 240Hz.

Now, let's assume that someone wants to use a fairly significant subwoofer boost. An 8db boost using something such as DEQ, or through independent subwoofer boosts, would not be at all uncommon. Instead of being down by 8db at 160Hz, the subwoofer would still be playing that frequency at the same volume level that it would have been playing, if there hadn't been a boost. And, the LFE channel is already playing 10db hotter than the regular channels.

It is easy to see that the subwoofer boost, occurring above 120Hz could make the bass in the LFE channel sound a little heavy. It is also easy to see how that boost above 120Hz could make the subwoofers strain a little more, depending on the overall listening/subwoofer volume. Very few subwoofers can play as clearly, with as little strain or compression, at 160Hz as they can at 120Hz. Rolling-off the LFE channel, above 80Hz, can help to alleviate that potential issue.

The same thing happens in the regular channels, but starting at a lower frequency, if an 80Hz crossover is being employed. Just a 6db boost (which is very modest for some people) would make the 100Hz frequency play as loudly as the 80Hz frequency would have played without the boost. Again, it is easy to imagine that the extra boost for the center channel (above 80Hz) could make some male voices sound a little more chesty, as bass fundamentals were amplified. And, that in-turn, could make dialogue sound a little thicker and a little less intelligible. Again, rolling-off the subs a little faster, above the crossover, helps to alleviate that issue where it is an audible problem."


There is also a more detailed explanation, further down in that section, for why dialogue intelligibility might be compromised with bass boosts above 80Hz. I think it is particularly noticeable with some male voices. And, let's face it, with ambient audio effects in the background, and some actors not enunciating as clearly as they might, we sometimes need all the help we can get.

Belated Happy Thanksgiving!

Regards,
Mike
@mthomas47

Your post #1639 above renewed my interest in CC. Since I last tried it, I changed to a Yamaha 2070 AVR. This AVR has NO LFE settings..That I know of? So, is the CC technique even doable?

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post #1646 of 1648 Old 12-04-2019, 09:29 PM - Thread Starter
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@mthomas47

Your post #1639 above renewed my interest in CC. Since I last tried it, I changed to a Yamaha 2070 AVR. This AVR has NO LFE settings..That I know of? So, is the CC technique even doable?

Hi Chuck,

Sorry that I couldn't respond to your question sooner--a pesky business trip.

The answer to your question is yes. Cascading crossovers are still doable and could still be worthwhile. The following is from the Cascading Crossovers Section (III-C) of the Guide:

"(Some AVR's, such as Yamaha AVR's, don't allow the LPF of LFE to be changed. It always remains at the default setting of 120Hz. If so, it is no problem. Setting the LPF in the subwoofer itself to 80Hz will still have full effect on the crossovers from the speakers to the subwoofer, and the low-frequency effects channel will still roll-off a little faster, too. So, the concept of cascading crossovers will still work.)"

Regards,
Mike
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GUIDE TO SUBWOOFER CALIBRATION AND BASS PREFERENCES

* The Guide linked above is a comprehensive guide to Audio & HT systems, including:
Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.
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post #1647 of 1648 Old 12-05-2019, 07:23 AM
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Hi Chuck,

Sorry that I couldn't respond to your question sooner--a pesky business trip.


"(Some AVR's, such as Yamaha AVR's, don't allow the LPF of LFE to be changed. Setting the LPF in the subwoofer itself to 80Hz will still have full effect on the crossovers from the speakers to the subwoofer, and the low-frequency effects channel will still roll-off a little faster, too. So, the concept of cascading crossovers will still work.)"

Regards,
Mike
Thanks, sorry I missed that entry.. Me bad, as they say. You're talking "setting the sub plate amp". Has to be, since there is no "in the subwoofer setting"; perhaps "on" the subwoofer would be better?

Happy Holidays
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post #1648 of 1648 Old 12-06-2019, 06:39 PM
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Thanks, sorry I missed that entry.. Me bad, as they say. You're talking "setting the sub plate amp". Has to be, since there is no "in the subwoofer setting"; perhaps "on" the subwoofer would be better?

Happy Holidays
Hi Chuck,

First try the Auto function, and if you find the sub does not always turn. Or go on stand by, during some content that does not have much bass. Just leave-it On, since most subs now a day use very little energy when not playing.


Darth

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