Dual SVS PB16 Ultra vs. Dual JTR Captivator 2400 in 2300 cubic foot room - Page 3 - AVS Forum | Home Theater Discussions And Reviews
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post #61 of 142 Old 03-07-2020, 12:07 PM
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Originally Posted by Hopinater View Post
That's a great way to describe it.

When you first get into this rabbit hole of a hobby you think bass is bass, it's the deep stuff. But no, bass is not just bass. Bass has layers and layers of nuances and to experience it at its best you need to experience as many of its frequencies as you can. A LT sub delivers bass with much more weight to it than a higher tuned sub, which sounds a little hollow in comparison to the LT sub. And strangely enough, the LT sub seems to deliver that weight even in scenes without significant ULF in it. That weight may not be for everyone, but for me it's addicting.

I think we are all actually saying the same thing! Low-bass frequencies are very addicting for sure, and lower port tunes are an important factor in our bass enjoyment. But, just how low do they need to be?

You went from about a 20Hz-tuned sub to the 10Hz-tuned Cap 2400ULF's, and you were immediately aware of the deeper bass. I believe that some of that was because the proportions of mid-bass and low-bass bass were also different. You noticed a lot more ULF TR with those subs than you had been getting before, especially on your concrete slab, and that also contributed to the bass weight that you enjoyed.

But, you ended-up sending those subs back, for other reasons, and later you ended-up with 14Hz-tuned subs (your TV36 iPal's). And, you love the low-bass in those subs too, even though the ULF TR isn't quite as impactful. Part of what you enjoy is the clearer sound signature of your current subs.

But, you really weren't responsive to the differences between the 10Hz port tune and the 14Hz port tune, in and of themselves, because both of those port tunes allowed the subs to play frequencies which are below your ability to distinguish tonality. And, if someone offered to trade you another (functional, this time ) pair of 10Hz-tuned Cap 2400ULF's, for your 14Hz-tuned TV36 iPal's, I am confident that you would say "No thanks!".

So lower port tunes are extremely important down to about the mid-teens or so, but below about 14-16Hz, they aren't a primary factor in your subwoofer selection. I suspect that, had you tried a pair of PB16's, after you got rid of your earlier V3611's, your impression of them would have been very similar to your impression of the Cap 2400ULF's. It has been for other people who have heard both subs. More low-bass, at frequencies where you can't hear tonality anyway, and lots of ULF TR.

So, lower port tunes are always better, except when they aren't! And, they aren't, for many of us at least, when they don't really make much difference in what we can actually hear.

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 #62 of 142 Old 03-07-2020, 12:14 PM
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I have officially worn out my “Like” finger because of so many great posts in this discussion. Yesterday I was telling a very good friend that this thread was derailing. But to my great pleasure, the conversation has remained cordial and respectful!

Happy to be once again, proven wrong!

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post #63 of 142 Old 03-07-2020, 12:54 PM
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Originally Posted by mthomas47 View Post
I think we are all actually saying the same thing! Low-bass frequencies are very addicting for sure, and lower port tunes are an important factor in our bass enjoyment. But, just how low do they need to be?

You went from about a 20Hz-tuned sub to the 10Hz-tuned Cap 2400ULF's, and you were immediately aware of the deeper bass. I believe that some of that was because the proportions of mid-bass and low-bass bass were also different. You noticed a lot more ULF TR with those subs than you had been getting before, especially on your concrete slab, and that also contributed to the bass weight that you enjoyed.

But, you ended-up sending those subs back, for other reasons, and later you ended-up with 14Hz-tuned subs (your TV36 iPal's). And, you love the low-bass in those subs too, even though the ULF TR isn't quite as impactful. Part of what you enjoy is the clearer sound signature of your current subs.

But, you really weren't responsive to the differences between the 10Hz port tune and the 14Hz port tune, in and of themselves, because both of those port tunes allowed the subs to play frequencies which are below your ability to distinguish tonality. And, if someone offered to trade you another (functional, this time ) pair of 10Hz-tuned Cap 2400ULF's, for your 14Hz-tuned TV36 iPal's, I am confident that you would say "No thanks!".

So lower port tunes are extremely important down to about the mid-teens or so, but below about 14-16Hz, they aren't a primary factor in your subwoofer selection. I suspect that, had you tried a pair of PB16's, after you got rid of your earlier V3611's, your impression of them would have been very similar to your impression of the Cap 2400ULF's. It has been for other people who have heard both subs. More low-bass, at frequencies where you can't hear tonality anyway, and lots of ULF TR.

So, lower port tunes are always better, except when they aren't! And, they aren't, for many of us at least, when they don't really make much difference in what we can actually hear.

Regards,
Mike
I think there does seem to be a sweet spot for port tune and that seems to be in the 14 to 16Hz range. I remember Tom telling me he tried different tuning points for the TV36 and he kept coming back to 14 Hz as what sounded best to him. I will add that LT subs also need to be powerful enough to play the ULF with authority and still have plenty enough power left in the amp to effectively deliver the key mid bass frequencies. IMO a good LT sub is able to deliver both great ULF as well as great Mid-bass, you can't give up one for the other.

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post #64 of 142 Old 03-07-2020, 01:18 PM
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Low tune does add presence and weight without bloating the sound even with frequencies above the tuning point. You don't need material playing in the 10-15 hz at extreme levels to realize the difference.
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With the LT sub the whole presentation of the bass changes in a way that (at least to me) is much more engaging and thrilling and that difference is with you all the time, every time the sub hits.
I am glad that you guys finally got to experience and agree with what I have been saying for years. The 3D sound is what I believe the LT subs can bring. IMO, even with music content of 30hz and above, LT subs still sound better with more 3D enveloping sound. And with Beq’ed movies rapidly available nowadays , LT sub is a MUST.
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post #65 of 142 Old 03-07-2020, 01:19 PM
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Originally Posted by basshead81 View Post
Honestly it's not entirely all about more extension and spl. Low tune does add presence and weight without bloating the sound even with frequencies above the tuning point. You don't need material playing in the 10-15 hz at extreme levels to realize the difference. It would be nice to see some smaller low tune options become available so more people can experience this. Low tune ported is similar to Atmos in the sense it adds another layer to the sound. I wouldn't say it's nearly as dramatic of a difference as Atmos has made to surround but it is there. It isn't life changing and I could easily get by with what I had, but I do enjoy having a 10hz tune sub added to my room. I wouldn't be surprised if we see some lower tune options from SVS in the near future which would be a good thing because they make a solid product with the CS to back it up!!
Good to know. This is probably a case of I don’t know what I don’t know. Admittedly I have not been paying too much attention to the very low tuned sub (10hz) discussions. I can certainly understand going from your relatively higher tuned PSA subs to the low tuned JTR noticing significantly more bass weight. I experienced that moving up the SVS line. I would not have thought there would be as much a difference comparing the fairly low tuned pb16s to the 10hz tuned subs but I have no experience and will defer to those who have directly compared. Hopefully one day I’ll have a dedicated theater space in our basement and will get to make some of these fun choices. Right now I’m stuck with my space saving cylinder subs but still consider myself lucky I have gotten approval for them in our living room.
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post #66 of 142 Old 03-07-2020, 01:26 PM
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That sweet spot is for the drivers involved, not what tune is best for everybody. I tried all sorts of drivers whether in horns, ported, low ported sealed, and IB. The deeper extension the better. The problem with comparing subs with different drivers and tunes is that there are more variables than just the tune. The Ipal drivers are superior to others in the midbass and when tuned to 12-14hz they check all the boxes. The JTR driver did not have as good as midbass, especially comparing one 18 vs two ipal per sub. So when you switched to the JTR it would not have that midbass impact along with the ULF. If it did, maybe he would have preferred the lower tune. That is where the 4000 comes into play, double 18s with 6 dB more midbass as well as the 10hz tune. In my experiences once you have the midbass exactly where you want the lower you go the better overall experience. I don't buy or build based on what I feel or can notice, I do it to cover as much material as possible. BTW, just putting sealed subs in a room does not cut it either, it requires enough of them for the output and low distortion one wants and especially the proper signal shaping to get the right weight and TR.

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post #67 of 142 Old 03-07-2020, 06:21 PM - Thread Starter
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Well this appears to be the best I can do in my room. Let me know your thoughts on if there is anything I can improve. Not sure if Ed over on the SVS thread can do anything but i'm open to suggestions from anyone on how to improve the performance above 75hz.

These test results reflect the best I could get from having the subs in the front corners of the room which is where they best fit. I may be able to move the front right sub out from the corner up to 4 feet but it sure won't look pretty. These measurements included fiddling around with the distance post Audyssey and extended and non extended mode.

My initial Audyssey settings created with all ports open mode yielded the Denon 4400 -11dB and -10.5db initial sub trim levels with both subs set to -24dB volume. I then adjusted the sub trim up 5dB landing at -6dB and -5.5dB.

The tests depicted in this graph show extended (green) and non-extended mode (red) at -40MV and a -15 sub volume.

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post #68 of 142 Old 03-07-2020, 06:35 PM
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@acribb what is the crossover on your speakers? AFAIK denon AVRs have a crossover for the LFE channel and for your speakers. I see you keep mentioning that the LFE crossover is at 120 (which it should be) but you never mentioned your speaker crossover (unless they are all at 120?). The response above 70Hz looks filtered to me but it's hard to tell.

You're not running your mains at the same time when doing these sweeps right?

Someone with a Denon AVR may be able to help you out more.

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post #69 of 142 Old 03-07-2020, 07:45 PM - Thread Starter
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Originally Posted by DarkEnigma View Post
@acribb what is the crossover on your speakers? AFAIK denon AVRs have a crossover for the LFE channel and for your speakers. I see you keep mentioning that the LFE crossover is at 120 (which it should be) but you never mentioned your speaker crossover (unless they are all at 120?). The response above 70Hz looks filtered to me but it's hard to tell.

You're not running your mains at the same time when doing these sweeps right?

Someone with a Denon AVR may be able to help you out more.
I'm only testing LFE with the Timing Reference Output set to L.

The mains are set to small and I moved the crossover from 40 to 60hz post Audyssey set up.

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post #70 of 142 Old 03-07-2020, 11:00 PM
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A much better value than either of these options, would be GSG Audio, 18" Ultimax drivers, and NX6000D amp. Going dual GSG Full Marty's would be the best value/performance possible, short of DIY.
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post #71 of 142 Old 03-07-2020, 11:18 PM
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Originally Posted by DarkEnigma View Post
@acribb what is the crossover on your speakers? AFAIK denon AVRs have a crossover for the LFE channel and for your speakers. I see you keep mentioning that the LFE crossover is at 120 (which it should be) but you never mentioned your speaker crossover (unless they are all at 120?). The response above 70Hz looks filtered to me but it's hard to tell.



You're not running your mains at the same time when doing these sweeps right?



Someone with a Denon AVR may be able to help you out more.


Just for clarity, the LFE doesn’t have a XO. It’s just an LPF for the .1 only.
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post #72 of 142 Old 03-08-2020, 07:04 AM
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I'm only testing LFE with the Timing Reference Output set to L.

The mains are set to small and I moved the crossover from 40 to 60hz post Audyssey set up.

I would try raising the crossover to 80 or even 100 and try again.
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post #73 of 142 Old 03-08-2020, 08:14 AM
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Well this appears to be the best I can do in my room. Let me know your thoughts on if there is anything I can improve. Not sure if Ed over on the SVS thread can do anything but i'm open to suggestions from anyone on how to improve the performance above 75hz.

These test results reflect the best I could get from having the subs in the front corners of the room which is where they best fit. I may be able to move the front right sub out from the corner up to 4 feet but it sure won't look pretty. These measurements included fiddling around with the distance post Audyssey and extended and non extended mode.

My initial Audyssey settings created with all ports open mode yielded the Denon 4400 -11dB and -10.5db initial sub trim levels with both subs set to -24dB volume. I then adjusted the sub trim up 5dB landing at -6dB and -5.5dB.

The tests depicted in this graph show extended (green) and non-extended mode (red) at -40MV and a -15 sub volume.

Quote:
Originally Posted by acribb View Post
I'm only testing LFE with the Timing Reference Output set to L.

The mains are set to small and I moved the crossover from 40 to 60hz post Audyssey set up.

I like the additional low-end SPL you picked-up, using the porting technique I suggested. How does it sound now?

Perhaps like several others reading the thread, I'll admit I'm a little confused at this point, though. If you are only testing the LFE channel, then your crossovers to your speakers don't matter. Once you have done a little more problem-solving with just the subwoofers, I would like to see a combined measurement of subwoofers and speakers, because that will much more closely replicate what you will be hearing. The measurements are much more valuable when we can correlate them to what we can actually hear, and I'm interested in seeing what happens when the subs and speakers are combined.

To that end, I would recommend raising your crossovers to 80Hz, rather than 60Hz, to start with. You can always drop down once you see, and hear, what is happening. But, coming from an AVR setting of 40Hz, I would recommend going up another full octave, to 80Hz. Your speakers will still be playing below 80Hz, but at a reduced volume level, just as your subwoofers will still be playing above 80Hz, but at a reduced level. (It is possible that a 60Hz crossover will work better, in this case, if the subwoofer roll-off above 72Hz persists. But, I would still default to an 80Hz crossover to begin with.)

With respect to the drop-off in the LFE channel, above about 72Hz, adding in your front speakers, or your center channel, won't change that, as the LFE channel is completely independent of the other channels, and has no relationship to your bass-management. If pulling one subwoofer forward a foot or so helps with the >72Hz response, then it might be worthwhile to try it.

You will just need to experiment to find out whether moving one of the subs a little helps. I also wonder whether the relationship between your subs and your listening position is a factor. Try doing some sweeps a foot or so in front of, and behind, your listening position. If it makes a difference, you might try adjusting your seating a little.

If you really can't fix the roll-off above 72Hz now, though, I'm not sure how much practical difference in your sound the roll-off will actually make. Here is what I mean by that. Although the LFE channel is theoretically designed to play bass frequencies up to 120Hz, several audio experts including Mark Seaton and Roger Dressler (formerly of Dolby Labs) have claimed that there is little meaningful content in the LFE channel above about 80Hz. Several film mixers have confirmed this notion, in some AVS discussion threads, from several years ago.

The LFE channel was created to augment low-frequency special effects in 5.1 movies. It plays the same low-bass content that the regular channels do, but it plays that content +10dB louder than the regular channels. And, the Dolby/THX standards were always based on an assumed 80Hz crossover from the subwoofers to the speakers. THX-rated speakers are specifically designed to use an 80Hz crossover. So, it makes sense that although the LFE channel can go up to 120Hz (and beyond at a reduced volume level) that the intent of the channel was always to amplify low-bass frequencies and not just bass frequencies in general. (The LFE channel was also intended to be played exclusively by subwoofers, and most subwoofers play their best, with the lowest distortion, below about 100Hz.)

The idea that there is relatively little meaningful content in the LFE channel (as opposed to random bass noise) above 80Hz, has led many listeners to try setting the LPF of LFE to 80Hz. And, that in-turn, has led many people to try cascading crossovers (explained in Section III-C of the Guide linked below). When cascading crossovers are implemented, the subs are deliberately rolled-off faster above 80Hz, and naturally that roll-off is actually starting below 80Hz.

With very few exceptions, the people who have reported trying that technique, on AVS, have reported clearer and somewhat punchier bass, and have chosen to run their HT systems that way. (At least three people I can recall, have preferred to maintain the higher LPF setting in order to have louder sounding bass above 80Hz.) Like everything in audio, it is a YMMV issue, but the bottom line is that a roll-off at 72Hz may not be a disaster, and you may not notice it at all. You just wouldn't need to implement cascading crossovers.

If I were you, I would still experiment a bit to see if I could improve on the overall subwoofer FR above 70Hz. And then, I would also measure to see how things look when you add in the front speakers (or the center channel). That won't affect what happens in the LFE channel, but you still want to know how your subwoofers and speakers integrate with about an 80Hz crossover.

Above all, I would stop and listen periodically, to determine whether there were any audible correspondence to the things I was measuring, and the things I was hearing. That will help you to decide whether you are headed in positive directions, and it will also help you to know how far you want to take your experimentation and problem-solving efforts.

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.

Last edited by mthomas47; 03-08-2020 at 08:49 AM.
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post #74 of 142 Old 03-08-2020, 09:04 AM
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JTR all day, any day....or PSA and Rythmik for that matter. SVS is going to have the lowest return on investment.

Or jump down the DIY rabbit hole and hit 125dBs at 16Hz and enough midbass to tear your drywall down with a 21" LFE Devastator.
I agree with above statement as far as midbass is concerned. I have 2 21" Devastators but not the LFE versions (thinking about building them). I have had 18" Mini Marty using UXL 18 from DIY SG and their build quality is top notch. Comparing the two, Devastators are miles ahead of Mini Marty. Don't get me wrong. Mini Marty are amazing subs and when it comes to low bass (30Hz and below), they do GREAT job but the Devs mid-bass is just so punchy and clean and effortless . Currently, I'm running 2 Mini Marty and 2 Devs together to cover all 3 seats and get both worlds and they work together well but keep thinking of What if I replace Mini Marty with Dev LFE
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post #75 of 142 Old 03-08-2020, 09:56 AM
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None of these prebuilt units come close to a DIY. The output of a single Devastator is close to 4 PB16s for ~$1,200.
This made me laugh out load. So true not to mention the satisfaction one gets after accomplishing it with your own hands.
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post #76 of 142 Old 03-08-2020, 10:51 AM
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Perhaps like several others reading the thread, I'll admit I'm a little confused at this point, though. If you are only testing the LFE channel, then your crossovers to your speakers don't matter.
Someone can correct me if I'm wrong but the reason I brought it up is because I wasn't sure how OP was obtaining the sub response.

I believe the Java drivers with REW only output in stereo, there is no LFE output. If he was simply disconnecting his mains the response he'd see would be based on the front crossover not the LFE channel LPF.

If he's using ASIO drivers correctly then there should be no issue.

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post #77 of 142 Old 03-08-2020, 11:18 AM
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Someone can correct me if I'm wrong but the reason I brought it up is because I wasn't sure how OP was obtaining the sub response.

I believe the Java drivers with REW only output in stereo, there is no LFE output. If he was simply disconnecting his mains the response he'd see would be based on the front crossover not the LFE channel LPF.

If he's using ASIO drivers correctly then there should be no issue.

My friend, Adam @Adamg (Ret-Navy) had suggested a workaround to this issue, which I started to add to my post. And, I should have! He said, in effect, that it might be helpful to raise the front speaker crossovers to 120Hz, just for the purpose of the LFE sweeps, in order to avoid the issue of the roll-off above about 72Hz.

Regards,
Mike
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post #78 of 142 Old 03-08-2020, 02:01 PM
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With this talk of how low tuned subs provide almost a different dimension of bass versus higher tuned subs, does this really only include ported subs, or could sealed subs provide the same effect, as long as they are tuned low enough? I'm in no way trying to derail this thread, but I'm trying to decide on a sub (with a small footprint) for a similar sized room, only difference being it is on a concrete slab.

Taking PSA subs for example, the S1812 has a lower frequency response as well as a much lower listed in-room extension than the ported V1812. I've read a lot about the advantages of a ported sub, but what would the ported V1812 provide that the sealed S1812 does not, especially in a room that is ~2,000 cubic ft.?
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post #79 of 142 Old 03-08-2020, 02:43 PM
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Originally Posted by Swoosh830 View Post
With this talk of how low tuned subs provide almost a different dimension of bass versus higher tuned subs, does this really only include ported subs, or could sealed subs provide the same effect, as long as they are tuned low enough? I'm in no way trying to derail this thread, but I'm trying to decide on a sub (with a small footprint) for a similar sized room, only difference being it is on a concrete slab.

Taking PSA subs for example, the S1812 has a lower frequency response as well as a much lower listed in-room extension than the ported V1812. I've read a lot about the advantages of a ported sub, but what would the ported V1812 provide that the sealed S1812 does not, especially in a room that is ~2,000 cubic ft.?

Hi,

We all end-up saying this a lot on AVS, but your question is more complicated than it sounds. Ported subs typically provide more SPL, below 50Hz, than the same model sealed sub would. That is partly due to the slighter larger cabinet volume of the ported sub. Within about an octave of the ported sub's port tune, the ports augment the SPL capabilities of the ported sub. That would be at about 45Hz, in the case of the V1812. From several graphs of the frequency response of the V1812, that have been posted in various threads, it appears that the port tune may be in about the 20-22Hz range.

By the time the ported subwoofer is near its port tune, it will be several times as powerful as the sealed sub. In the case of the V1812, it might be equal to three or more sealed S1812's at about 20-22Hz. Below 20Hz, however, the ported V1812 drops-off very fast, with what looks in some posted graphs to be a 32dB per octave high-pass filter. (An octave is a doubling in frequency.)

The S1812 rolls-off much more slowly than the V1812, which gives it more theoretical extension than the V1812. But, the problem is that the S1812 just isn't actually producing much volume by the time it gets to 20Hz, when the V1812 begins its rapid roll-off. Extension, as a theoretical concept, is pretty meaningless unless there is enough SPL, at some particular low-frequencies, to really be heard.

One of the points of emphasis in this thread, in the discussions of lower-tuned subs, is the importance of hearing enough low-frequency SPL in relation to the mid-bass. Otherwise, the mid-bass frequencies, which we hear better anyway, just drown-out the lower-frequencies. The low-frequencies have to be loud enough to call some attention to themselves in order to convey the impression of "bass weight", and in order to carry the low-frequency special effects in movies.

With a single sealed sub, it is much harder to do that. It certainly can be done with a sufficient number of sealed subs, but it would be very difficult for an S1812 to sound as loud as a V1812 at any frequency below about 50Hz. Room gain will help the smaller sealed sub, but it will also be helping the relatively high-tuned ported sub down to about 18-20Hz. And, the S1812 just won't be loud enough at those frequencies for room gain to help it in a very audible way.

Think of room gain as sort of like speaking into a megaphone. If you shout into the megaphone, the megaphone will make your voice very loud. If, on the other hand, you just whisper into the megaphone, there simply won't be enough sound for the megaphone to amplify it very much at all. Room gain is a little bit like that with sealed and ported subs.

Room gain amplifies more, as frequencies go lower, and that can really help sealed subs if they can produce enough SPL at very low-frequencies, because their roll-off is more gradual. But, there still has to be enough inherent volume, produced by either ported or sealed subwoofers, at those low-frequencies, for the amplification to really be noticeable.

Personally, I would still probably prefer the ported V1812, in a 2000^3 room. That would be especially true on concrete, which won't convey as much tactile energy, as a suspended wood floor will. (Ported subs produce more low-frequency vibrations, which we feel as tactile sensations, due to air moving through the ports--producing particle velocity.)

But, if I really had my choice, I would probably look for a ported subwoofer with a lower port tune than the V1812. That's sort of the general theme of this thread--that port tunes in at least the mid-teens are preferable to port tunes of around 20Hz. As with sealed subs, though, multiple higher-tuned ported subs can help to make-up for the limitations of a single sub, especially in a smaller room where there is more room gain. I hope this 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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None of these prebuilt units come close to a DIY. The output of a single Devastator is close to 4 PB16s for ~$1,200.
This made me laugh out load. So true not to mention the satisfaction one gets after accomplishing it with your own hands.
Yep, DIY destroys commercial. And with GSG Audio, they make the DIY aspect way easier.
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post #81 of 142 Old 03-08-2020, 07:17 PM - Thread Starter
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I double checked and everything is set to measure LFE on a Mac using the Mac guide. Sound is DEFINITELY only coming from the Subs!!

I moved the couch back a foot and got this. Not much difference. I really can't move the subs anywhere else so I guess this is what I am stuck with. It sounds good but i'm still debating exploring the JTR Cap 2400s. I just need to decide if the looks are worth the perceived performance increase with the JTRs because these subs are extremely nice looking and look good in my room.

I also played around with the speaker crossovers and moving them did nothing as would be expected.

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post #82 of 142 Old 03-08-2020, 08:13 PM
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I double checked and everything is set to measure LFE on a Mac using the Mac guide. Sound is DEFINITELY only coming from the Subs!!

I moved the couch back a foot and got this. Not much difference. I really can't move the subs anywhere else so I guess this is what I am stuck with. It sounds good but i'm still debating exploring the JTR Cap 2400s. I just need to decide if the looks are worth the perceived performance increase with the JTRs because these subs are extremely nice looking and look good in my room.

I also played around with the speaker crossovers and moving them did nothing as would be expected.

I'd be interested to see your max clean sweep results. With my setup I have <10% distortion from 15hz up at 0MV + 13 with -12dbfs test tones. I start at -20MV 0 DB hot and increase 5db at a time. Also make sure your Umik is calibrated for higher volume. Mine came at -12dbfs out of the box which means 118db volumes before clipping.

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post #83 of 142 Old 03-09-2020, 03:09 AM - Thread Starter
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I double checked and everything is set to measure LFE on a Mac using the Mac guide. Sound is DEFINITELY only coming from the Subs!!

I moved the couch back a foot and got this. Not much difference. I really can't move the subs anywhere else so I guess this is what I am stuck with. It sounds good but i'm still debating exploring the JTR Cap 2400s. I just need to decide if the looks are worth the perceived performance increase with the JTRs because these subs are extremely nice looking and look good in my room.

I also played around with the speaker crossovers and moving them did nothing as would be expected.

I'd be interested to see your max clean sweep results. With my setup I have <10% distortion from 15hz up at 0MV + 13 with -12dbfs test tones. I start at -20MV 0 DB hot and increase 5db at a time. Also make sure your Umik is calibrated for higher volume. Mine came at -12dbfs out of the box which means 118db volumes before clipping.
Matt - Can you elaborate on how you tested? Do you have dual PB16s and you are talking about testing both together at the same time? The volume slider on my PB16Us was calibrated by Audyssey at -24db which I then moved up to -15db and then moved the sub trim in the Denon up from -11 to -5db. This is what I would consider my minimum bass listening level. Are you saying to put my subs at 0 dB volume and then test at -20db MV and up in 5db increments with both subs on until a clipping pattern emerges? I guess I'm confused from your earlier statement that says something about + 13db. Notice the plus sign.
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post #84 of 142 Old 03-09-2020, 07:34 AM
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He is saying to do some compression sweep testing like I mentioned in the PSA thread when you were posting over there.

Start with the volume at MV-20 and run a REW sweep from 10-200hz. Then raise the volume to -15 and run another sweep, then -10, -5, -2, 0...etc. If you see compression before getting to MV 0( any part of the response does not increase in SPL at the same rate you increased the volume level), then stop there, click All SPL which will over lay the measurements, and post up the results.
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He is saying to do some compression sweep testing like I mentioned in the PSA thread when you were posting over there.

Start with the volume at MV-20 and run a REW sweep from 10-200hz. Then raise the volume to -15 and run another sweep, then -10, -5, -2, 0...etc. If you see compression before getting to MV 0( any part of the response does not increase in SPL at the same rate you increased the volume level), then stop there, click All SPL which will over lay the measurements, and post up the results.
What should the sub volume be at? See my above post for where Audyssey initially set it.
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post #86 of 142 Old 03-09-2020, 08:31 AM
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He is saying to do some compression sweep testing like I mentioned in the PSA thread when you were posting over there.

Start with the volume at MV-20 and run a REW sweep from 10-200hz. Then raise the volume to -15 and run another sweep, then -10, -5, -2, 0...etc. If you see compression before getting to MV 0( any part of the response does not increase in SPL at the same rate you increased the volume level), then stop there, click All SPL which will over lay the measurements, and post up the results.
If you compress at say 11 hz but the rest of the range has lots of life left then should you stop sweeping? For ULF compression I keep sweeping if 95% of the shape stays the same.

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post #87 of 142 Old 03-09-2020, 08:36 AM
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Matt - Can you elaborate on how you tested? Do you have dual PB16s and you are talking about testing both together at the same time? The volume slider on my PB16Us was calibrated by Audyssey at -24db which I then moved up to -15db and then moved the sub trim in the Denon up from -11 to -5db. This is what I would consider my minimum bass listening level. Are you saying to put my subs at 0 dB volume and then test at -20db MV and up in 5db increments with both subs on until a clipping pattern emerges? I guess I'm confused from your earlier statement that says something about + 13db. Notice the plus sign.
Yeah I have dual PB16s. I would start the tests running 0db hot, so for the test move your trims back to -11db and the PB16 gain back to 24db, run a test at -20MV or whatever your minimum level would be. Then add 5db to each sweep. 1db = 1db so 1MV = 1db at amp = 1db in the AVR trim. Side note if you have dynamic eq enabled I noticed increasing MV by 5 does NOT increase the sweep 5db, more like 3db. I've never seen that mentioned before but I suppose most people do their sweeps with audyssey off so they don't encounter it, I accidentally encountered it one time when I forgot to disable audyssey. So if you run your sweeps with Audyssey turned on just make sure to turn dynamic EQ off. Then click on the overlays tab to see each sweep piling on top of the other, the shapes of the sweep should stay the same up until the point compression occurs. You can also track distortion at high levels using the overlays tab.

As it gets louder you may want to plug your ears

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post #88 of 142 Old 03-09-2020, 09:46 AM
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If you compress at say 11 hz but the rest of the range has lots of life left then should you stop sweeping? For ULF compression I keep sweeping if 95% of the shape stays the same.
I do because that is your max output capability full bandwidth. Sure you might be able to go louder at higher frequencies but I don't like to run the subs into compression with test tone sweeps.
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post #89 of 142 Old 03-09-2020, 11:12 AM
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Originally Posted by acribb View Post
I double checked and everything is set to measure LFE on a Mac using the Mac guide. Sound is DEFINITELY only coming from the Subs!!

I moved the couch back a foot and got this. Not much difference. I really can't move the subs anywhere else so I guess this is what I am stuck with. It sounds good but i'm still debating exploring the JTR Cap 2400s. I just need to decide if the looks are worth the perceived performance increase with the JTRs because these subs are extremely nice looking and look good in my room.

I also played around with the speaker crossovers and moving them did nothing as would be expected.

Spoiler!
I will reiterate what has been already mentioned multiple times; you need to measure the subs plus a speaker (center channel if mostly movies, left or right if mostly music) to get a better representation of your final frequency response around and above the crossover. You don't listen to subs only.
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post #90 of 142 Old 03-09-2020, 11:17 AM
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FYI, I did play around with the phase on 1 of the subwoofers adjusting it in 20 degree increments and then measuring with REW. It only worsened the response.

I will play around some more tonight with recalibration, different placement and distance settings.
Get yourself a miniDSP HD. Much better option. As to how to find out if subs if subs are off phase is to take Sub Only measurement in REW with Acoustic Timing Reference On. Then take readings of both (or as many subs you have) indivisually. Once done, go to Overlay screen and click on Impulse. See if their first impulse are in same direction, If they are not, then the phases are not matching.

Now, things get complicated a bit here. Just because phases are inverted b/w subs doesn't mean that you'd get bad response. Best is to check in both ways. Here is what you should do (example assumes you have 2 subs)

1 - Set max crossover in your AVR.
2 - Turn all processing off in your AVR.
3 - Make sure you have Acoustic Timing Reference on.Take reading of first sub. Make sure its only your sub and nothing else (no other channel)
4 - Take reading of 2nd sub.
5 - Take reading of both subs. Combined response should be better their individual responses. To get the best combined response, do the following
a) check if their polarity are same (impulse response). If not then invert polarity of 1 one of the sub and then take reading and see if it gets better.
b) Now time to play with delays on the sub that is closer to MLP. Change delay on the sub by 1ft and see if it gets better. Keep doing it till you get best response.
Another way to simply the delay is to find the difference b/w the two sub impulse in Impulse screen but that's a bit advance if you have never done it. So other
option is to just manually change distance to add more delay to the sub closer to MLP.

Good luck.
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