Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 361 - AVS Forum
Forum Jump: 
 11Likes
Reply
 
Thread Tools
post #10801 of 10830 Old Yesterday, 04:57 PM
AVS Special Member
 
AustinJerry's Avatar
 
Join Date: Jan 2003
Location: Austin, Texas
Posts: 6,828
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 239 Post(s)
Liked: 650
Quote:
Originally Posted by Alan P View Post

Adding more subs won't necessarily get you flatter, but it will make the response flat over a wider area (less seat-to-seat variance).
Not necessarily true, Alan. By carefully placing multiple subs, there can be a measurable flattening of the frequency response, both at the MLP, and over the wider area.

I have provided an example: AustinJerry's Set-Up
Alan P likes this.
AustinJerry is online now  
Sponsored Links
Advertisement
 
post #10802 of 10830 Old Yesterday, 05:18 PM
Advanced Member
 
IgorZep's Avatar
 
Join Date: Sep 2012
Posts: 562
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 45 Post(s)
Liked: 70
Quote:
Originally Posted by HDgaming42 View Post
Is this as true for music as for movies?
Don't you have music in movies you are watching? Sure it is true!

Quote:
Originally Posted by HDgaming42 View Post
I see advice like the following posted around the net...
If we tell about acoustics when we tell about the distance we actually tell about the delay. As long as you have control on the delay you have control on the acoustic distance. The physical distance doesn't matter and with subs is usually differ from acoustical one. Up to 80Hz with 24db/oct slope (acoustical one again, electrical doesn't matter) works best.

The rules you quoted apply if you do not have decent bass management in your processor.
IgorZep is offline  
post #10803 of 10830 Old Yesterday, 08:49 PM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,809
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 170 Post(s)
Liked: 151
Quote:
Originally Posted by AustinJerry View Post
Not necessarily true, Alan. By carefully placing multiple subs, there can be a measurable flattening of the frequency response, both at the MLP, and over the wider area.

I have provided an example: AustinJerry's Set-Up
I'm aware Jerry, that's why I said "won't necessarily".

Since HD is only worried about a flat response at the MLP and isn't considering multiple subs at this time, I think we can safely forego any multiple sub scenario for now.
Alan P is online now  
post #10804 of 10830 Old Today, 07:32 AM
Senior Member
 
KevinG's Avatar
 
Join Date: Apr 2002
Location: S. Jersey
Posts: 458
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 28 Post(s)
Liked: 13
Quote:
Originally Posted by HDgaming42 View Post
Next up--I'm guessing--will be to treat the back wall. My back corners have a door on one side, and a cubby for an equipment rack on the other, so no easy way to trap those corners unfortunately.
I haven't done my back wall yet (that's next), but I did see a huge improvement when my ceiling panels went up.

Pictures here of the entire process so far:
http://imgur.com/a/YOLoo

I suspect that this has more to do with surface area more than anything else. These are basically 4' x 4' or 16 square feet each. So, there's 64 square feet of absorption up there. Six inches thick + 2 inch air gap.

I'm planning on doing about 40 square feet (5 panels of 2' x 4') on the rear wall. (6" + 2" again, but this time with Roxul AFB instead of the pink fluffy that is in the cloud). I suspect that will help as well.

-Kevin
KevinG is online now  
post #10805 of 10830 Old Today, 09:10 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,266
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 55 Post(s)
Liked: 79
http://www.audiocheck.net/audiotests...calization.php
Low Frequency Sound Localization Test

This test will help you determine at what frequency localization in the bass region ceases. Download the files and listen. On my ears and system, localization seemed to definitely suffer starting at about 80hz, and was completely gone by 50hz. ( I ignored the part about turning off my subs for I wanted to see how things are perceived in my room as I normally listen to them).

In further reading today, I am not sure there is a universal number. The size of your woofers, speakers in general, and room size all seem to play a part. With all this talk recently of sub XO points and such, I wanted to gain more depth on the subject. 80hz gets tossed around as the prime XO a lot. Perhaps for good reason. But there maybe means to extend localization lower through better understanding.

My Room
http://www.gearslutz.com/board/studio-building-acoustics/817205-my-listening-room.html

My Music
http://rateyourmusic.com/~jim1961

My Equipment

Rega - Apollo
Rega - DAC
Goldpoint Passive
(2) Classe CA-100 bridged power amps (350w)
Jenzen Next ( http://www.troelsgravesen.dk/Jenzen-NEXT.htm )
...

Last edited by jim19611961; Today at 09:17 AM.
jim19611961 is online now  
post #10806 of 10830 Old Today, 09:10 AM
Advanced Member
 
HDgaming42's Avatar
 
Join Date: Sep 2006
Location: Alberta, Canada
Posts: 502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 10
Quote:
Originally Posted by KevinG View Post
I haven't done my back wall yet (that's next), but I did see a huge improvement when my ceiling panels went up.

Pictures here of the entire process so far:
http://imgur.com/a/YOLoo

I suspect that this has more to do with surface area more than anything else. These are basically 4' x 4' or 16 square feet each. So, there's 64 square feet of absorption up there. Six inches thick + 2 inch air gap.

I'm planning on doing about 40 square feet (5 panels of 2' x 4') on the rear wall. (6" + 2" again, but this time with Roxul AFB instead of the pink fluffy that is in the cloud). I suspect that will help as well.

-Kevin
I've checked out your progress in the past--didn't realize you were still going! Do you have before and after graphs? Could be good to motivate myself!
HDgaming42 is offline  
post #10807 of 10830 Old Today, 10:31 AM
Senior Member
 
KevinG's Avatar
 
Join Date: Apr 2002
Location: S. Jersey
Posts: 458
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 28 Post(s)
Liked: 13
Quote:
Originally Posted by HDgaming42 View Post
I've checked out your progress in the past--didn't realize you were still going! Do you have before and after graphs? Could be good to motivate myself!
Yep, still going...just a bit slower now. :-) I have 2 more "wall panels" mostly built, but not sure where to put them (if anywhere).

I have mental plans for how to build the rear wall panels, but haven't purchased the wood for it yet.

I *do* have before and after graphs. Mostly I was concentrating on the impulse graphs to try to get things down by 20db within 20ms. I'm not quite there yet, but the overall drop is huge. I actually haven't really looked at SPL over the spectrum recently...nor have I measured with Audyssey turned back on. I should get around to doing that.

Anyway, I'll try to find time to put together a post with the before and after graphs soon. They aren't subtle.

-Kevin
KevinG is online now  
post #10808 of 10830 Old Today, 10:43 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,266
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 55 Post(s)
Liked: 79
Quote:
Originally Posted by KevinG View Post
Yep, still going...just a bit slower now. :-) I have 2 more "wall panels" mostly built, but not sure where to put them (if anywhere).

I have mental plans for how to build the rear wall panels, but haven't purchased the wood for it yet.

I *do* have before and after graphs. Mostly I was concentrating on the impulse graphs to try to get things down by 20db within 20ms. I'm not quite there yet, but the overall drop is huge. I actually haven't really looked at SPL over the spectrum recently...nor have I measured with Audyssey turned back on. I should get around to doing that.

Anyway, I'll try to find time to put together a post with the before and after graphs soon. They aren't subtle.

-Kevin
Posting before/after room measurements are probably the most helpful, encouraging and inspiring posts we can make. Not to single you out, we should all do this.

To start this tradition, here is my first FR for the right channel. I had mild treatment at that time. Additionally, I have changed main speakers and added subs as well.

then and now 07 30.jpg
(1/24th octave smoothing)

Red = Then
Green = Now

My ETC data only goes back about a year, and look similar to now, so I didnt post them.

My Room
http://www.gearslutz.com/board/studio-building-acoustics/817205-my-listening-room.html

My Music
http://rateyourmusic.com/~jim1961

My Equipment

Rega - Apollo
Rega - DAC
Goldpoint Passive
(2) Classe CA-100 bridged power amps (350w)
Jenzen Next ( http://www.troelsgravesen.dk/Jenzen-NEXT.htm )
...

Last edited by jim19611961; Today at 10:54 AM.
jim19611961 is online now  
post #10809 of 10830 Old Today, 10:49 AM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,809
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 170 Post(s)
Liked: 151
Quote:
Originally Posted by jim19611961 View Post
http://www.audiocheck.net/audiotests...calization.php
Low Frequency Sound Localization Test

This test will help you determine at what frequency localization in the bass region ceases. Download the files and listen. On my ears and system, localization seemed to definitely suffer starting at about 80hz, and was completely gone by 50hz. ( I ignored the part about turning off my subs for I wanted to see how things are perceived in my room as I normally listen to them).

In further reading today, I am not sure there is a universal number. The size of your woofers, speakers in general, and room size all seem to play a part. With all this talk recently of sub XO points and such, I wanted to gain more depth on the subject. 80hz gets tossed around as the prime XO a lot. Perhaps for good reason. But there maybe means to extend localization lower through better understanding.
...and, sometimes you may think you're localizing when your really not. Case in point; I've had subs in the rear of my room and thought I could localize them (particularly in the right rear, closest to MLP) but when I moved all subs up front, I still get a "sense" of more bass emanating from the right rear corner.

The room plays a big part in all of this, more than may seem apparent at times.
Alan P is online now  
post #10810 of 10830 Old Today, 10:54 AM
Senior Member
 
3ll3d00d's Avatar
 
Join Date: Sep 2007
Location: London, UK
Posts: 299
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 58 Post(s)
Liked: 26
Quote:
Originally Posted by jim19611961 View Post
http://www.audiocheck.net/audiotests...calization.php
Low Frequency Sound Localization Test

This test will help you determine at what frequency localization in the bass region ceases. Download the files and listen. On my ears and system, localization seemed to definitely suffer starting at about 80hz, and was completely gone by 50hz. ( I ignored the part about turning off my subs for I wanted to see how things are perceived in my room as I normally listen to them).

In further reading today, I am not sure there is a universal number. The size of your woofers, speakers in general, and room size all seem to play a part. With all this talk recently of sub XO points and such, I wanted to gain more depth on the subject. 80hz gets tossed around as the prime XO a lot. Perhaps for good reason. But there maybe means to extend localization lower through better understanding.
I can't find the link now but I have read something in the past on this subject that suggests that, while your ability to localise such frequencies is weak, you can still perceive some element of the interaural phase difference & hence multiple, non colocated, subs are beneficial to SQ not just via the effect on frequency response. This paper provides some evidence to support that (though I don't know whether this has since been refuted)

Another point that I'm sure I've come across before is that higher frequency content will effectively steer your perception of the LF content. This argues against using localisation as the only criteria for setting the XO as most content is not just purely LF energy (i.e. your perception of direction will be dominated by the accompanying HF energy).

In general I can't see how you can push the localisation boundary lower (short of growing a giant head) but I can see ways you could push it higher.
3ll3d00d is online now  
post #10811 of 10830 Old Today, 11:07 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,266
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 55 Post(s)
Liked: 79
Quote:
Originally Posted by 3ll3d00d View Post
I can't find the link now but I have read something in the past on this subject that suggests that, while your ability to localise such frequencies is weak, you can still perceive some element of the interaural phase difference & hence multiple, non colocated, subs are beneficial to SQ not just via the effect on frequency response. This paper provides some evidence to support that (though I don't know whether this has since been refuted)

Another point that I'm sure I've come across before is that higher frequency content will effectively steer your perception of the LF content. This argues against using localisation as the only criteria for setting the XO as most content is not just purely LF energy (i.e. your perception of direction will be dominated by the accompanying HF energy).

In general I can't see how you can push the localization boundary lower (short of growing a giant head) but I can see ways you could push it higher.
What I meant was, we may be inadvertently/artificially pushing it higher than need be. No, we are not going to surpass the capacity of the human condition, but there may be aspects of our setup that contribute to it being higher than it should.

I agree that the harmonics of lower register instruments/sources steer our perception of localization given they are easier to localize. I am not saying low frequency localization should be the only thing to consider for your XO point. But I submit it as one among many.

If one does the test I mentioned, and localization is already difficult at 200hz, for instance, I would say that something is interfering with your ability to make this discernment, and quite possibly a setup correction is in order.

My Room
http://www.gearslutz.com/board/studio-building-acoustics/817205-my-listening-room.html

My Music
http://rateyourmusic.com/~jim1961

My Equipment

Rega - Apollo
Rega - DAC
Goldpoint Passive
(2) Classe CA-100 bridged power amps (350w)
Jenzen Next ( http://www.troelsgravesen.dk/Jenzen-NEXT.htm )
...

Last edited by jim19611961; Today at 11:20 AM.
jim19611961 is online now  
post #10812 of 10830 Old Today, 11:10 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,266
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 55 Post(s)
Liked: 79
Quote:
Originally Posted by Alan P View Post
...and, sometimes you may think you're localizing when your really not. Case in point; I've had subs in the rear of my room and thought I could localize them (particularly in the right rear, closest to MLP) but when I moved all subs up front, I still get a "sense" of more bass emanating from the right rear corner.

The room plays a big part in all of this, more than may seem apparent at times.
That is a good case in point. A phenomena I would try to fix if I could.

My Room
http://www.gearslutz.com/board/studio-building-acoustics/817205-my-listening-room.html

My Music
http://rateyourmusic.com/~jim1961

My Equipment

Rega - Apollo
Rega - DAC
Goldpoint Passive
(2) Classe CA-100 bridged power amps (350w)
Jenzen Next ( http://www.troelsgravesen.dk/Jenzen-NEXT.htm )
...
jim19611961 is online now  
post #10813 of 10830 Old Today, 11:49 AM
Senior Member
 
KevinG's Avatar
 
Join Date: Apr 2002
Location: S. Jersey
Posts: 458
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 28 Post(s)
Liked: 13
Quote:
Originally Posted by jim19611961 View Post
To start this tradition, here is my first FR for the right channel. I had mild treatment at that time. Additionally, I have changed main speakers and added subs as well.

Attachment 187962
(1/24th octave smoothing)

Red = Then
Green = Now
Very nice. Is "before" without room correction, and after with room correction? (meaning electronic correction, not treatments).

I plan on posting before (without Audyssey), after (without Audyssey), and after (with Audyssey).
KevinG is online now  
post #10814 of 10830 Old Today, 11:50 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,266
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 55 Post(s)
Liked: 79
Quote:
Originally Posted by KevinG View Post
Very nice. Is "before" without room correction, and after with room correction? (meaning electronic correction, not treatments).

I plan on posting before (without Audyssey), after (without Audyssey), and after (with Audyssey).
I don't have or use processors of any kind, now or before.

Edit: Come to think of it, there was some EQ on the "before"(red) graph.

My Room
http://www.gearslutz.com/board/studio-building-acoustics/817205-my-listening-room.html

My Music
http://rateyourmusic.com/~jim1961

My Equipment

Rega - Apollo
Rega - DAC
Goldpoint Passive
(2) Classe CA-100 bridged power amps (350w)
Jenzen Next ( http://www.troelsgravesen.dk/Jenzen-NEXT.htm )
...

Last edited by jim19611961; Today at 12:43 PM.
jim19611961 is online now  
post #10815 of 10830 Old Today, 01:23 PM
Advanced Member
 
HDgaming42's Avatar
 
Join Date: Sep 2006
Location: Alberta, Canada
Posts: 502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 10
Quote:
Originally Posted by KevinG View Post
Very nice. Is "before" without room correction, and after with room correction? (meaning electronic correction, not treatments).

I plan on posting before (without Audyssey), after (without Audyssey), and after (with Audyssey).
Ultimately if I could be selfish--this is what I'd love to see from those able to post their results. And the resulting waterfalls would be interesting too.
HDgaming42 is offline  
post #10816 of 10830 Old Today, 01:23 PM
Senior Member
 
3ll3d00d's Avatar
 
Join Date: Sep 2007
Location: London, UK
Posts: 299
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 58 Post(s)
Liked: 26
Quote:
Originally Posted by jim19611961 View Post
What I meant was, we may be inadvertently/artificially pushing it higher than need be. No, we are not going to surpass the capacity of the human condition, but there may be aspects of our setup that contribute to it being higher than it should.

I agree that the harmonics of lower register instruments/sources steer our perception of localization given they are easier to localize. I am not saying low frequency localization should be the only thing to consider for your XO point. But I submit it as one among many.

If one does the test I mentioned, and localization is already difficult at 200hz, for instance, I would say that something is interfering with your ability to make this discernment, and quite possibly a setup correction is in order.
(I agree with the above) the interesting thing there is that there are systems that deliberately run *much* higher crossovers. An example of that is a steinway lyngdorf setup. IIRC these crossover to a pair of corner loaded 12" woofers at ~400Hz (as per e.g. http://www.steinwaylyngdorf.com/tech...oundary-woofer) and sound pretty impressive to say the least (as you'd hope they would for >£50k!). It's never been entirely clear to me how they get away with this given the physical constraints of localisation.
3ll3d00d is online now  
post #10817 of 10830 Old Today, 01:44 PM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,809
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 170 Post(s)
Liked: 151
Quote:
Originally Posted by HDgaming42 View Post
Ultimately if I could be selfish--this is what I'd love to see from those able to post their results. And the resulting waterfalls would be interesting too.
My system, Audyssey Off:



Audyssey On:



As you can see, I've got a giant null to contend with as well.
Alan P is online now  
post #10818 of 10830 Old Today, 01:50 PM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,809
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 170 Post(s)
Liked: 151
And the corresponding waterfalls:

Aud Off:



Aud On:

Alan P is online now  
post #10819 of 10830 Old Today, 02:39 PM
Advanced Member
 
HDgaming42's Avatar
 
Join Date: Sep 2006
Location: Alberta, Canada
Posts: 502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 10
Which flavour of audyssey is that? I've got XT32 on my 805, so I'm hopeful it can perform similar magic.
HDgaming42 is offline  
post #10820 of 10830 Old Today, 02:46 PM
Senior Member
 
3ll3d00d's Avatar
 
Join Date: Sep 2007
Location: London, UK
Posts: 299
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 58 Post(s)
Liked: 26
Quote:
Originally Posted by HDgaming42 View Post
Which flavour of audyssey is that? I've got XT32 on my 805, so I'm hopeful it can perform similar magic.
fwiw Onkyo 805 has MultEQ XT not XT32 though I believe they are effectively the same when it comes to the sub
3ll3d00d is online now  
post #10821 of 10830 Old Today, 03:12 PM
Advanced Member
 
HDgaming42's Avatar
 
Join Date: Sep 2006
Location: Alberta, Canada
Posts: 502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 10
Quote:
Originally Posted by 3ll3d00d View Post
fwiw Onkyo 805 has MultEQ XT not XT32 though I believe they are effectively the same when it comes to the sub*
Right you are. I missed a Denon X4000 being clearanced locally for $800. I must still be living in the alternate reality where I picked it up before it sold out.

Doing a bit of reading it looks like XT32 has 32x the filtering of XT (go figure!) and 4x the filtering for subs.

This is where I'm hoping Alan P didn't require 4x the filtering I have available to me and accomplished that with regular old XT (or less).

Last edited by HDgaming42; Today at 03:44 PM. Reason: realized Alan P's graph was up to 200Hz
HDgaming42 is offline  
post #10822 of 10830 Old Today, 03:52 PM
AVS Special Member
 
AustinJerry's Avatar
 
Join Date: Jan 2003
Location: Austin, Texas
Posts: 6,828
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 239 Post(s)
Liked: 650
Quote:
Originally Posted by HDgaming42 View Post
Which flavour of audyssey is that? I've got XT32 on my 805, so I'm hopeful it can perform similar magic.
If you look closely at the waterfalls, I don't see a significant difference in bass resonance with Audyssey on or off. The frequency response improves with Audyssey on, which is expected, but Audyssey has marginal impact on reducing resonance. There was a lengthy discussion earlier in this thread regarding the relationship between room correction and resonance, and there were a number of examples provided that demonstrated that room correction actually made resonance worse.

As you attempt to improve your bass response, be aware that taming resonance is just as important as smoothing the frequency response.
AustinJerry is online now  
post #10823 of 10830 Old Today, 04:05 PM
Senior Member
 
KevinG's Avatar
 
Join Date: Apr 2002
Location: S. Jersey
Posts: 458
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 28 Post(s)
Liked: 13
As promised, here are my ETC differences. I haven't done any Audyssey measurements recently. As I said, I'm focusing mostly on ETC, not SPL, for now... I had massive slap echo (clapping hands, or clucking tongue) in this room before...and it's going away pretty quickly at this point. :-)

All ETC graphs go out to 0.06 of a second...As I understand it, the first 0.02 are important, but I include 3x that amount so you can see the drastic effect the treatments are having on the long term reverb in this room.

First, the left speaker with no treatments (well, aside from the entire front wall's massive bass trap).



Next, the left speaker with the 3 panels on the left wall. The effects are there, but they are somewhat subtle. They appear more when zoomed in a little closer than this.



Lastly, the left speaker with the ceiling 4 traps, and the other 3 traps on the right side wall...Now we're talkin'!



I suspect (and hope, very strongly) that those spikes at around 14 and 16 ms go away when I treat the back wall. They show up in all graphs, including other front speaker channels...so it must be the shared rear wall (or, at least that's what I'm telling myself).
Attached Images
File Type: jpg etc_left_no_panels.jpg (73.3 KB, 28 views)
File Type: jpg etc_left_3_panels.jpg (72.6 KB, 26 views)
File Type: jpg etc_left_6_panels_with_ceiling.jpg (64.4 KB, 24 views)
KevinG is online now  
post #10824 of 10830 Old Today, 04:15 PM
Senior Member
 
3ll3d00d's Avatar
 
Join Date: Sep 2007
Location: London, UK
Posts: 299
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 58 Post(s)
Liked: 26
Quote:
Originally Posted by AustinJerry View Post
As you attempt to improve your bass response, be aware that taming resonance is just as important as smoothing the frequency response.
(my bold) is it? I thought we were *relatively* insensitive to decay times at sub frequencies, i.e. it's not unimportant but if you had to choose then choose frequency response
3ll3d00d is online now  
post #10825 of 10830 Old Today, 04:46 PM
Advanced Member
 
artur9's Avatar
 
Join Date: Mar 2013
Location: near philly
Posts: 689
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 40
Quote:
Originally Posted by jim19611961 View Post
http://www.audiocheck.net/audiotests...calization.php
Low Frequency Sound Localization Test

This test will help you determine at what frequency localization in the bass region ceases. Download the files and listen. On my ears and system, localization seemed to definitely suffer starting at about 80hz, and was completely gone by 50hz. ( I ignored the part about turning off my subs for I wanted to see how things are perceived in my room as I normally listen to them).

In further reading today, I am not sure there is a universal number. The size of your woofers, speakers in general, and room size all seem to play a part. With all this talk recently of sub XO points and such, I wanted to gain more depth on the subject. 80hz gets tossed around as the prime XO a lot. Perhaps for good reason. But there maybe means to extend localization lower through better understanding.
I'm hoping to run some flanking sub experiments this weekend (or next). Mostly to try to get rid of floor bounce but also because I feel like my subs are a bit too localizable.

The flanking sub guy(s) says that subs are localizable to 50Hz. I'll see for myself.
artur9 is online now  
post #10826 of 10830 Old Today, 05:06 PM
AVS Special Member
 
mogorf's Avatar
 
Join Date: May 2009
Location: Budapest, Hungary
Posts: 4,262
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 95 Post(s)
Liked: 101
Quote:
Originally Posted by artur9 View Post
I'm hoping to run some flanking sub experiments this weekend (or next). Mostly to try to get rid of floor bounce but also because I feel like my subs are a bit too localizable.

The flanking sub guy(s) says that subs are localizable to 50Hz. I'll see for myself.
Localization of low frequencies is an interesting phenomenon. Read on here please:

From Chris Kyriakakis (CTO of Audyssey Labs):

AUDYSSEY BLOG

March 27, 2009


Small vs. Large

Do you have a subwoofer in your system? Great. Then your speakers are small. Before you get all upset, read on. This is one of those audio myths whose time has come to be busted. To understand why, we need to talk about Bass Management.

In the early days of home theater it was thought that in order to reproduce the full movie surround experience at home it was necessary to place 5 large loudspeakers in the room. The reason for the size was the woofers. To play at theatrical reference levels and reproduce the deepest bass available in the content requires each speaker to have 12” or larger woofers. Let’s just say that this theory didn’t get very far in the real world.

A better and more practical approach came after studying human perception. The mechanisms that we use to determine the direction of arrival of sound depend on the frequency. At high frequencies the wavelength of sound is small and so sound coming from the side is shadowed by our head. That creates a level difference between the sound reaching the ear closest to the source and the ear on the other side. Our brain analyzes these level differences and produces an estimate of where the sound is coming from. But at lower frequencies, the wavelength of sound gets longer and our head is not large enough to produce a level difference at the two ears. Instead, we analyze the difference in time of arrival of sound at the two ears. Sound arrives first at the closest ear and we use that to determine the direction. But even that ability fails us below about 80 Hz. The wavelengths get very large and it was found in listening tests that 80 Hz is the frequency below which most people can not localize the direction of sound.

Taking advantage of this apparent “deficiency” in our hearing was what made home theater practical for millions of homes. Five satellite speakers of reasonable size could now be used because they no longer required large woofers. A subwoofer (or two) can reproduce the lower octaves and it can be placed out of sight since its content is not directional.

But there is also a practical advantage: directing the bass to a dedicated subwoofer channel with its own amplifier greatly improves the headroom in the main channels. The idea behind this was proposed in a Society of Motion Picture Engineers (SMPTE) meeting in 1987. The participants could not agree on the minimum number of channels required for surround sound on film. Various numbers were being shouted out until a voice was heard from the back: “We need 5.1”. Everyone’s head turned around to look at Tom Holman. He proceeded to explain what he meant: Take the low frequency content from all 5 channels and redirect it away from the satellite speakers to the subwoofer. If we do the math, then the content below 80 Hz is 0.004 of the audible 20,000 Hz bandwidth. But 5.004 didn’t sound as catchy so Tom rounded up to 5.1. By the way, don’t make the amateur mistake of calling it 5 dot 1. It is a decimal: 5 point 1.

Fast forward to the early 90s when the first DSP powered home theater receivers started to appear. Along with progress came complexity. Some industry forces believed that Bass Management should be an option that could be turned on and off by the consumer. That’s not necessarily a bad idea, but to make an informed decision requires much more knowledge about the system than what was available to the typical consumer. So, the Large and Small rule of thumb was established. The idea was to look at the size of your speakers and decide whether their woofers were “large enough” to reproduce the lowest octaves at the required levels. It was a noble thought, but looking at it 15 years later I believe that it has led to nothing but massive confusion. The poor consumer was led to believe that Large is somehow a good thing and was then left wondering why there was nothing coming out of their subwoofer.

Redirecting the bass to the subwoofer relieves the receiver amplifiers from having to work on reproducing the low frequencies and this greatly improves the headroom. If you happen to be using Audyssey MultEQ for room correction, you will achieve much better low frequency performance because the MultEQ subwoofer filters have 8x higher resolution than the filters in the other channels.

Here is a better rule: All speakers are Small. In today’s complicated AVR lingo that just means: If you have a subwoofer you should always turn bass management on. Always. Even if your receiver clings to the past and automatically sets your speakers to Large.
mogorf is online now  
post #10827 of 10830 Old Today, 05:19 PM
AVS Special Member
 
mogorf's Avatar
 
Join Date: May 2009
Location: Budapest, Hungary
Posts: 4,262
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 95 Post(s)
Liked: 101
Quote:
Originally Posted by 3ll3d00d View Post
fwiw Onkyo 805 has MultEQ XT not XT32 though I believe they are effectively the same when it comes to the sub
XT32 has 4 times the resolution of XT in the sub channel. 512x vs. 128x:


Last edited by mogorf; Today at 05:22 PM.
mogorf is online now  
post #10828 of 10830 Old Today, 05:24 PM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,266
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 55 Post(s)
Liked: 79
Quote:
Originally Posted by KevinG View Post
As promised, here are my ETC differences. I haven't done any Audyssey measurements recently. As I said, I'm focusing mostly on ETC, not SPL, for now... I had massive slap echo (clapping hands, or clucking tongue) in this room before...and it's going away pretty quickly at this point. :-)

All ETC graphs go out to 0.06 of a second...As I understand it, the first 0.02 are important, but I include 3x that amount so you can see the drastic effect the treatments are having on the long term reverb in this room.

First, the left speaker with no treatments (well, aside from the entire front wall's massive bass trap).



Next, the left speaker with the 3 panels on the left wall. The effects are there, but they are somewhat subtle. They appear more when zoomed in a little closer than this.



Lastly, the left speaker with the ceiling 4 traps, and the other 3 traps on the right side wall...Now we're talkin'!



I suspect (and hope, very strongly) that those spikes at around 14 and 16 ms go away when I treat the back wall. They show up in all graphs, including other front speaker channels...so it must be the shared rear wall (or, at least that's what I'm telling myself).
These are not ETC (envelope) graphs.

My Room
http://www.gearslutz.com/board/studio-building-acoustics/817205-my-listening-room.html

My Music
http://rateyourmusic.com/~jim1961

My Equipment

Rega - Apollo
Rega - DAC
Goldpoint Passive
(2) Classe CA-100 bridged power amps (350w)
Jenzen Next ( http://www.troelsgravesen.dk/Jenzen-NEXT.htm )
...
jim19611961 is online now  
post #10829 of 10830 Old Today, 05:37 PM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,266
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 55 Post(s)
Liked: 79
Quote:
Originally Posted by AustinJerry View Post
If you look closely at the waterfalls, I don't see a significant difference in bass resonance with Audyssey on or off. The frequency response improves with Audyssey on, which is expected, but Audyssey has marginal impact on reducing resonance. There was a lengthy discussion earlier in this thread regarding the relationship between room correction and resonance, and there were a number of examples provided that demonstrated that room correction actually made resonance worse.

As you attempt to improve your bass response, be aware that taming resonance is just as important as smoothing the frequency response.
In addition, it was also shown that those areas where processing filled in nulls was often areas of significant distortion levels.

My Room
http://www.gearslutz.com/board/studio-building-acoustics/817205-my-listening-room.html

My Music
http://rateyourmusic.com/~jim1961

My Equipment

Rega - Apollo
Rega - DAC
Goldpoint Passive
(2) Classe CA-100 bridged power amps (350w)
Jenzen Next ( http://www.troelsgravesen.dk/Jenzen-NEXT.htm )
...
jim19611961 is online now  
post #10830 of 10830 Old Today, 05:56 PM
Senior Member
 
KevinG's Avatar
 
Join Date: Apr 2002
Location: S. Jersey
Posts: 458
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 28 Post(s)
Liked: 13
Quote:
Originally Posted by jim19611961 View Post
These are not ETC (envelope) graphs.
Hmm, you are right.

I got confused by the "Envelope (ETC)" at the bottom of the "Filtered IR" window.

Oops...back to the drawing board.

Actually, the real Impulse Envelope (ETC) graphs show effectively the exact same thing...I'm going to go save them, and post them, but the point remains valid.

Here they are in order, none, 3, and 6 plus ceiling. This time I left the cursor in at -20db.





Attached Images
File Type: jpg etc_left_no_panels.jpg (103.3 KB, 7 views)
File Type: jpg etc_left_3_panels.jpg (105.0 KB, 5 views)
File Type: jpg etc_left_6_panels_with_ceiling.jpg (108.2 KB, 4 views)

Last edited by KevinG; Today at 06:04 PM.
KevinG is online now  
Reply Audio theory, Setup and Chat

Tags
Dayton , Dayton Audio , Room Equilizer Wizard Rew

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off