Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 362 - AVS Forum
Forum Jump: 
 12Likes
Reply
 
Thread Tools
post #10831 of 10859 Old Yesterday, 08:47 PM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,844
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 194 Post(s)
Liked: 154
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.
I just got pain ol' XT (Denon 2113ci).

Keep in mind that you need to find the proper placement before running Audyssey if you want good results. This is essential!

My placement in the graphs I posted are not ideal, I only have the subs placed where they are because I need (crave?) the output. I can get a much better response (without the nasty null) with different placement....it's a trade off. Sometimes you gotta make the difficult choices.

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.
True. But please note that my decay times are pretty darn good to start with and even get slightly better (under 40hz) post-Audyssey.

Quote:
Originally Posted by jim19611961 View Post
In addition, it was also shown that those areas where processing filled in nulls was often areas of significant distortion levels.
Yeah, my THD is up to about 7.6% around 60hz where Audyssey is trying to fill in the null...doesn't make me happy. Still a work in progress.
Alan P is online now  
Sponsored Links
Advertisement
 
post #10832 of 10859 Old Today, 06:18 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,276
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 61 Post(s)
Liked: 79
Quote:
Originally Posted by Alan P View Post
Yeah, my THD is up to about 7.6% around 60hz where Audyssey is trying to fill in the null...doesn't make me happy. Still a work in progress.
I suspected such was the case. You know, another sub running in just the area of the null, with proper placement, and XO alignment, might fill it in without the distortion increase

How many subs do you have presently?

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 07:03 AM.
jim19611961 is online now  
post #10833 of 10859 Old Today, 07:34 AM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,844
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 194 Post(s)
Liked: 154
Yeah Jim, the answer is always "more subs"!

Currently, I have 4 PSA XS15s in 2 stacks of 2 in the front of the room (~5000 cu. ft.). 2 up front/2 in back provides a nice smooth response with little distortion, but the subs ain't powerful enough to reach reference in that config....like I said, it's a trade off - and still a work in progress.

2 more XS15s would almost certainly solve all my issues.
Alan P is online now  
post #10834 of 10859 Old Today, 07:44 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,276
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 61 Post(s)
Liked: 79
Quote:
Originally Posted by Alan P View Post
Yeah Jim, the answer is always "more subs"!

Currently, I have 4 PSA XS15s in 2 stacks of 2 in the front of the room (~5000 cu. ft.). 2 up front/2 in back provides a nice smooth response with little distortion, but the subs ain't powerful enough to reach reference in that config....like I said, it's a trade off - and still a work in progress.

2 more XS15s would almost certainly solve all my issues.
Putting 2 in the back isnt loud enough ? (4) 15" high excursion 550w subs?

You must listen at levels far higher than I do (88-94SPLdb).

I have a total of (6) 10" drivers (including mains) that see only about 100 watts a piece and have limited excursion (7.6mm) in a somewhat smaller space (3200 cu ft).

In any case, apparently (havent seen graphs of that setup), you know how to get a flatter, undistorted sound if you want to.

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 08:05 AM.
jim19611961 is online now  
post #10835 of 10859 Old Today, 07:44 AM
Advanced Member
 
artur9's Avatar
 
Join Date: Mar 2013
Location: near philly
Posts: 690
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 40
Quote:
Originally Posted by Alan P View Post
Yeah Jim, the answer is always "more subs"!
Remember that the boffins over @ Harman did simulations with up to 5000 IIRC. So you've a ways to go.
artur9 is offline  
post #10836 of 10859 Old Today, 08:24 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,276
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 61 Post(s)
Liked: 79


Just get one of these and be done with it.

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 #10837 of 10859 Old Today, 08:27 AM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,844
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 194 Post(s)
Liked: 154
Quote:
Originally Posted by jim19611961 View Post
Putting 2 in the back isnt loud enough ? (4) 15" high excursion 550w subs?

You must listen at levels far higher than I do (88-94SPLdb).

I have a total of (6) 10" drivers (including mains) that see only about 100 watts a piece and have limited excursion (7.6mm) in a somewhat smaller space (3200 cu ft).

In any case, apparently (havent seen graphs of that setup), you know how to get a flatter, undistorted sound if you want to.
That's the thing...I almost never listen at reference, but I'd like to be able to whenever I want to. That being said, I've been thinking of trying the more spread-out, better response setup again....and you've got me thinking about it even more.

Audessey Off:



Audyssey On:

Alan P is online now  
post #10838 of 10859 Old Today, 08:33 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,276
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 61 Post(s)
Liked: 79
Quote:
Originally Posted by Alan P View Post
That's the thing...I almost never listen at reference, but I'd like to be able to whenever I want to.
That does look better to me.

When you say "reference", what is that exactly?

From what I have seen, and different people say different things, 110SPLdb minimum capability is considered a reference. My system barely gets there. I can only assume yours is much higher than this.

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 08:44 AM.
jim19611961 is online now  
post #10839 of 10859 Old Today, 09:03 AM
Advanced Member
 
HDgaming42's Avatar
 
Join Date: Sep 2006
Location: Alberta, Canada
Posts: 504
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 25 Post(s)
Liked: 10
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.
I'll go back and dig for this--sounds interesting. Looking at the waterfalls (I'm still learning!) this distortion you speak of regarding resonance shows as the increased length of the "fingers" around 50Hz? The additional poorly sloped "humps" that appear with Audyssey enagaged? Or am I misinterpreting that?
HDgaming42 is offline  
post #10840 of 10859 Old Today, 09:33 AM
Advanced Member
 
HDgaming42's Avatar
 
Join Date: Sep 2006
Location: Alberta, Canada
Posts: 504
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 25 Post(s)
Liked: 10
need a better analysis to data collection ratio!

It appears I have more data that shows a very similar result to REWs Room Simulator prediction(s).

The best result I had across the front wall:



And the furthest I measured into the room along the front wall:


I'd say the second graph shows more resonance, but a better FR. Trapping should address the resonance, so it is clear the second graph (deeper into the room) is a better placement for my sub, correct? The more I move the sub toward the rear of the room, the better the FR it seems. Highly impractical in my setting as I have a door, a bookcase and an equipment rack in the rear of the room, but worth pursuing a compromise I think.

(I intend on measuring everything that is feasible behind the MLP but starting at REWs best prediction. I can alter the MLP to fine tune as well)
Attached Images
File Type: png best along front wall.png (329.1 KB, 4 views)
File Type: png approaching rear of room.png (289.7 KB, 5 views)
HDgaming42 is offline  
post #10841 of 10859 Old Today, 09:49 AM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,844
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 194 Post(s)
Liked: 154
Quote:
Originally Posted by HDgaming42 View Post
I'll go back and dig for this--sounds interesting. Looking at the waterfalls (I'm still learning!) this distortion you speak of regarding resonance shows as the increased length of the "fingers" around 50Hz? The additional poorly sloped "humps" that appear with Audyssey enagaged? Or am I misinterpreting that?
To see the distortion, you have to look at the distortion graph in REW. Mostly concerned with the THD percentage as you scrub through the graph. You'll see the THD number in the lower right corner.

You really need to find a way to get that sub in the back of your room, it's really your only hope of the best response.
Alan P is online now  
post #10842 of 10859 Old Today, 09:51 AM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,844
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 194 Post(s)
Liked: 154
Quote:
Originally Posted by jim19611961 View Post
That does look better to me.

When you say "reference", what is that exactly?

From what I have seen, and different people say different things, 110SPLdb minimum capability is considered a reference. My system barely gets there. I can only assume yours is much higher than this.
0db on my MVC is what I mean when I say "reference". I really have no idea how loud that is since I've never really measured it...I would describe it as "really flippin' loud".
Alan P is online now  
post #10843 of 10859 Old Today, 10:03 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,276
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 61 Post(s)
Liked: 79
Quote:
Originally Posted by Alan P View Post
0db on my MVC is what I mean when I say "reference". I really have no idea how loud that is since I've never really measured it...I would describe it as "really flippin' loud".
How loud (by measurement) is it when it says -20db ?

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 #10844 of 10859 Old Today, 10:35 AM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,844
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 194 Post(s)
Liked: 154
I dunno, would have to measure.

With what content? A loud-ish BR, such as Pacific Rim??
Alan P is online now  
post #10845 of 10859 Old Today, 11:04 AM
Senior Member
 
3ll3d00d's Avatar
 
Join Date: Sep 2007
Location: London, UK
Posts: 302
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 59 Post(s)
Liked: 26
Quote:
Originally Posted by Alan P View Post
I dunno, would have to measure.

With what content? A loud-ish BR, such as Pacific Rim??
Reference capability, in a bass managed system, means being able to cleanly (say less than 10% distortion?) reproduce about 118dB (see http://www.avsforum.com/forum/155-diy-speakers-subs/1402484-subwoofer-spl-requirement-reference-117-34db-123-45db.html for details) from your subs. This assumes you target a flat response of course, ie no house curve.

You need a lot of sub to do that.

Last edited by 3ll3d00d; Today at 11:07 AM.
3ll3d00d is online now  
post #10846 of 10859 Old Today, 11:06 AM
Senior Member
 
JohnPM's Avatar
 
Join Date: Sep 2004
Location: UK
Posts: 448
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked: 19
Quote:
Originally Posted by jim19611961 View Post
These are not ETC (envelope) graphs.
Yes they are, they just have a linear amplitude axis (% FS) instead of log (dB FS).
JohnPM is offline  
post #10847 of 10859 Old Today, 11:37 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,276
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 61 Post(s)
Liked: 79
Quote:
Originally Posted by Alan P View Post
I dunno, would have to measure.

With what content? A loud-ish BR, such as Pacific Rim??
The REW sweep of course.

The point of this is, you will be 20db louder at 0db than at -20db. Additionally, the reference on your volume control doesnt mean much since different source material are not recorded at the same loudness.

If 0db on your amp is your reference, then that power level will vary greatly.

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 11:48 AM.
jim19611961 is online now  
post #10848 of 10859 Old Today, 11:47 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,276
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 61 Post(s)
Liked: 79
Quote:
Originally Posted by JohnPM View Post
Yes they are, they just have a linear amplitude axis (% FS) instead of log (dB FS).
Well, ok. What I meant was, this isn't the form of ETC we are using for comparison on this forum.

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 #10849 of 10859 Old Today, 01:03 PM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,844
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 194 Post(s)
Liked: 154
Quote:
Originally Posted by jim19611961 View Post
The REW sweep of course.

The point of this is, you will be 20db louder at 0db than at -20db. Additionally, the reference on your volume control doesnt mean much since different source material are not recorded at the same loudness.

If 0db on your amp is your reference, then that power level will vary greatly.
OK, REW sweep (at the default -12db I'm assuming), thanks I'll give it a go and post the results tonight.

But, why at -20 and not at 0 MV? Just so I don't bust my eardrums or kill small animals??

I thought that today's BluRays were mostly mastered to be at the same level, hence today's 0db MV = Reference Level....??

I don't know what you mean by your last statement...isn't 0db "reference" on everybody's amp (modern AVRs/pre-pros, if calibrated correctly)?

I'm relatively certain I recorded this measurement at -15 MV. What does that mean in reference to this discussion? That my max output is probably somewhere around 110db??

Alan P is online now  
post #10850 of 10859 Old Today, 01:05 PM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,844
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 194 Post(s)
Liked: 154
Oh, should I measure subs only or subs+mains?
Alan P is online now  
post #10851 of 10859 Old Today, 01:17 PM
Senior Member
 
KevinG's Avatar
 
Join Date: Apr 2002
Location: S. Jersey
Posts: 459
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 29 Post(s)
Liked: 13
Quote:
Originally Posted by jim19611961 View Post
Well, ok. What I meant was, this isn't the form of ETC we are using for comparison on this forum.
Can we at least agree that I saw a huge improvement once the ceiling panels were added? ;-)
KevinG is offline  
post #10852 of 10859 Old Today, 01:18 PM
Senior Member
 
3ll3d00d's Avatar
 
Join Date: Sep 2007
Location: London, UK
Posts: 302
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 59 Post(s)
Liked: 26
Quote:
Originally Posted by Alan P View Post
OK, REW sweep (at the default -12db I'm assuming), thanks I'll give it a go and post the results tonight.

But, why at -20 and not at 0 MV? Just so I don't bust my eardrums or kill small animals??

I thought that today's BluRays were mostly mastered to be at the same level, hence today's 0db MV = Reference Level....??

I don't know what you mean by your last statement...isn't 0db "reference" on everybody's amp (modern AVRs/pre-pros, if calibrated correctly)?
if you run a REW sweep on a system calibrated to AV standards with

MV = -20
REW sweep = -12dBFS

and output to a main channel then your target SPL is 105-20-12 = 73dB

if you send that output to the LFE channel then your target SPL is 115-20-12 = 83dB

"AV" reference is 105dB (mains) or 115dB (LFE) given a 0dBFS signal, note that dBFS is purely a relative measure where 0 = max possible level before the signal clips.

Generally speaking music, or anything other than AV, is not calibrated to the same level so AV reference != the same level when playing music for example. This is why standards like https://tech.ebu.ch/loudness exist. Jriver for example offers a volume levelling mode that applies R128 based levelling (not compression) to normalise gain across your entire library to the same (R128 dictated) level.
3ll3d00d is online now  
post #10853 of 10859 Old Today, 01:22 PM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,276
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 61 Post(s)
Liked: 79
Quote:
Originally Posted by Alan P View Post
OK, REW sweep (at the default -12db I'm assuming), thanks I'll give it a go and post the results tonight.

But, why at -20 and not at 0 MV? Just so I don't bust my eardrums or kill small animals??

I thought that today's BluRays were mostly mastered to be at the same level, hence today's 0db MV = Reference Level....??

I don't know what you mean by your last statement...isn't 0db "reference" on everybody's amp (modern AVRs/pre-pros, if calibrated correctly)?

I'm relatively certain I recorded this measurement at -15 MV. What does that mean in reference to this discussion? That my max output is probably somewhere around 110db??

Bold 1) Yes
Bold 2) If your AVR is accurate in db steps, and this is at -15db, then 110-112db would be your output in SPLdb for the REW sweep if your volume was set to 0db.. Your absolute maximum cant be determined unless you have a source that you know was recorded at 0db. Some test CD have tracks such as these.

All this is just a way to determine your max output at your reference of 0db on your AVR without trying to measure at that SPL level. You may not care. But since your stated at one point that turning it up to 0db was important to you, thought we would find out how loud that is or can be.

Edit: after reading 3II3's response, it occurred to me that AVR's have too many ways to manipulate the volume for us to do this properly. It appears in any case that your system gets plenty loud. Not sure if anything else really matters.

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 01:30 PM.
jim19611961 is online now  
post #10854 of 10859 Old Today, 01:35 PM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,276
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 61 Post(s)
Liked: 79
Quote:
Originally Posted by KevinG View Post
Can we at least agree that I saw a huge improvement once the ceiling panels were added? ;-)
Sure

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 #10855 of 10859 Old Today, 01:38 PM
AVS Special Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 1,844
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 194 Post(s)
Liked: 154
Thanks d00d and Jim, it's all coming clear now.