Corner Bass Traps - Always beneficial?

edorr

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May 10, 2010
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-----Which TRINNOV unit (component) do you have?

I have the ST2 - Pro. I am using it to do MCH (5.0) on the cheap. I run 3.0 through the Trinnov, and two other channels through another external DAC, and then the delay lines in the Trinnov. I synch up volume control through iRule macros. I am listening to stereo 80% of the time though.
 

edorr

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May 10, 2010
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Ah, I see. I would imagine that the measured response would be very different with both woofers active, please post some measurements once the woofer has been sorted out.

It has been sorted out long ago. However, I did measure with all woofers active before I put in the traps. The woofer defect did not really affect bass response. The curve shape (same null and peaks) was very similar, just a few DB louder. So with the 2 woofers inactive, I simply jacked up the output of the woofers a few Db and got a very similar reponse. In fact, the measurements you see are two woofers active with a few db gain on the woofers. Without this, my null would have been a few db worse.
 

NorthStar

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I have the ST2 - Pro. I am using it to do MCH (5.0) on the cheap. I run 3.0 through the Trinnov, and two other channels through another external DAC, and then the delay lines in the Trinnov. I synch up volume control through iRule macros. I am listening to stereo 80% of the time though.

-----Sorry, I should have known (ST2). Yes it is a stereo digital processor (room EQ).
Wow, it ain't free either (cost few bucks)!
 

edorr

WBF Founding Member
May 10, 2010
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-----Sorry, I should have known (ST2). Yes it is a stereo digital processor (room EQ).
Wow, it ain't free either (cost few bucks)!

it is actually full blown 4 channels of processing, and then you can run 2 or 4 more channels through the Trinnov to add systems delay. If you can get the synching up of volume control sorted out it works very well for multi channel, for less than half the price of the 8 channel unit. You run mains, center and LFE through the Trinnov, and surrounds through the delay channel. It is the poor man's (relatively speaking) MCH DRC solution...
 

The Bogg

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Jul 28, 2010
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It has been sorted out long ago. However, I did measure with all woofers active before I put in the traps. The woofer defect did not really affect bass response. The curve shape (same null and peaks) was very similar, just a few DB louder. So with the 2 woofers inactive, I simply jacked up the output of the woofers a few Db and got a very similar reponse. In fact, the measurements you see are two woofers active with a few db gain on the woofers. Without this, my null would have been a few db worse.

Ah I see. I must say I'm surprised that the response didn't have a different shape with the additional woofers b/c they would be asymmetrical (different distance to each boundary, suggesting a different frequency response leading to summation which would be different from just 2 woofers) but your results obviously show it not to be the case. More importantly, how do those giant handsets sound????
 

edorr

WBF Founding Member
May 10, 2010
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Ah I see. I must say I'm surprised that the response didn't have a different shape with the additional woofers b/c they would be asymmetrical (different distance to each boundary, suggesting a different frequency response leading to summation which would be different from just 2 woofers) but your results obviously show it not to be the case. More importantly, how do those giant handsets sound????

I was expecting more difference as well. But the measurements don't lie. Almost the same response curve for 2 and 4 woofers.

Bass extension is obviously phenomenal. Highs are very clean and free of any harshness. Mids are comparable to the avalons I had before, but with less stress, because there are two drivers not one.
 

edorr

WBF Founding Member
May 10, 2010
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Hey edorr, how's it going? Any pic of the other end of your room?

Here is the other end of the room. I'm sure I am violating some rules by using a couch instead of chair - convenience over acoustic optimization. The white frames in the wall are my in wall surround channels (B&WSignature 8 NT). The opening on the left closes with sliding door if I need total darkness for movie watching. The CDs in the rack are stictly archive. Everything has been ripped to harddrive. There are a bunch of SACD and Blu Rays I still spin.

RoomBack.JPG
 
Last edited:

NorthStar

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Here is the other end of the room. I'm sure I am violating some rules by using a couch instead of chair - convenience over perfection. The white frames in the wall are my in wall surround channels (B&WSignature 8 NT). The opening on the left closes with sliding door if I need total darkness for movie watching. The CDs in the rack are stictly archive. Everything has been ripped to harddrive. There are a bunch of SACD and Blu Rays I still spin.

View attachment 6342

-----Hi Ed,

Your surround speakers at the rear corners are your only surround speakers, right?
And please forgive me if I missed it previously, but what are the dimensions of that room?
...Fourteen feet wide perhaps? ...A bit less?

And thanks for showing this picture of your room's rear; it is quite interesting to have that opening in the rear center. I like what you did overall with the speaker's positioning and all that 'bass traps' jazz. :b
Your room is cool for the fact that not all the walls are parallel.
Even your ceiling is breaking off from one straight slab (surface).
And your couch is perfectly fine.
 

edorr

WBF Founding Member
May 10, 2010
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Smyrna, GA
-----Hi Ed,

Your surround speakers at the rear corners are your only surround speakers, right?
And please forgive me if I missed it previously, but what are the dimensions of that room?
...Fourteen feet wide perhaps? ...A bit less?

And thanks for showing this picture of your room's rear; it is quite interesting to have that opening in the rear center. I like what you did overall with the speaker's positioning and all that 'bass traps' jazz. :b
Your room is cool for the fact that not all the walls are parallel.
Even your ceiling is breaking off from one straight slab (surface).
And your couch is perfectly fine.

Yes, these are my only surround speakers. I actually have the wiring in the walls for 2 more (side) channels, but I'm not going to bother. My critical MCH listening is 5.1 SACD, which I doubt will benefit from 2 extra surrounds and some algorithm to generate the channels.

Room is 13' wide. I had to work with a lot of physical contraints when I finished my basement - mainly location of supporting walls. There was no space for free standing surrounds, so I asked the guys to frame out the corners so I could fit an in wall speaker. Not ideal, but it works good enough for me. The B&W have very good dispersion, and you do absolutely not hear anything coming from a point source. They just add ambiance (except for the odd old quadraphonic recording [e.g. Deep Purple Machine head] ported to SACD, which will have guitars blaring out of each separete corner).

Lack of good MCH material is still my biggest regret in audio. All the high rez stuff is marginally better to my ears (most of the time), but a very good discrete MCH recording is still my gold standard.
 

NorthStar

Member
Feb 8, 2011
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Yes, these are my only surround speakers. I actually have the wiring in the walls for 2 more (side) channels, but I'm not going to bother. My critical MCH listening is 5.1 SACD, which I doubt will benefit from 2 extra surrounds and some algorithm to generate the channels.

-----Perfect! :b ...No need for extras.

Room is 13' wide.

-----I knew it; I just didn't want to say it exactly. ...Honest! :b


I had to work with a lot of physical contraints when I finished my basement - mainly location of supporting walls. There was no space for free standing surrounds, so I asked the guys to frame out the corners so I could fit an in wall speaker. Not ideal, but it works good enough for me. The B&W have very good dispersion, and you do absolutely not hear anything coming from a point source. They just add ambiance (except for the odd old quadraphonic recording [e.g. Deep Purple Machine head] ported to SACD, which will have guitars blaring out of each separete corner).

-----You did an excellent job!

Lack of good MCH material is still my biggest regret in audio. All the high rez stuff is marginally better to my ears (most of the time), but a very good discrete MCH recording is still my gold standard.

-----In my signature, there is a link you can click on; there they have Multichannel Classical music selections (and Jazz too), on Hybrid SACDs. ...Probably that you already knew though.
 

stevekale

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Aug 8, 2012
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Room is 13' wide.

Very nice. I am about to grapple with a very difficult room that is 4.1m wide and 4.9m long but has an old fireplace and chimney protruding 0.8m into the room on the shorter side. Annoyingly, the fireplace/chimney isn't even centered in the room! And I have free-standing Eggleston Rosas as surround speakers.
 

kach22i

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Apr 21, 2010
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If this article has not been posted already in this very long thread, I'd be surprised. I just discovered it yesterday myself.

September 2011
How TubeTraps opened up a Whole New Realm of Precision in the Performance of Audio Playback Systems
Notes from the ASC Seminar at the 2nd CAS
Art Noxon
http://www.dagogo.com/View-Article.asp?hArticle=919
Publisher's note: The TubeTrap™ is a product of Acoustic Science Corporation. Art Noxon, president of the company, hosted three sessions of seminar at the recently concluded 2nd California Audio Show. Art has compiled his seminars into a single article, which he has graciously given to Dagogo for publishing. We are very grateful for the privilege, and we are proud to present his article to our readers in the following.
 

acousticsguru

Well-Known Member
Feb 17, 2014
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Sharing example of corner trapping

View attachment 4314 View attachment 4315 View attachment 4316 View attachment 4317 View attachment 4318

This room features a beautiful set of Vandersteens. Analysis showed the basic location of speakers and listening position is very good for the space. Treatments were design based on room data and predictive tools. In the front corners are RealTrap Mega and in sidewall/ceiling junctures are GIK Monster. The additional panels behind the speakers are in fact RPG 4" BAD panels which have a very good LF absorption ability. All of these devices reflect or diffuse mid/hi freq's...the goal is balance after all.

I'm sharing freq response graphs and Resonance Studies (Burst Decay) Pre & Post. In all cases the woofer amp is at same volume and the EQ is not engaged at all. After the final measurements you see, the Vandy EQ specialist came in and did his thing (I have no data after that stage but trust that the 42Hz peak was tucked down just a touch).

The LF response graphs have an overlay of the very same Impulse response but the smoothing is changed. So there is a Pre graph that shows both 1/24th oct and 1/3rd oct. Same with the Final (or post treatment).
This is most impressive, especially below 100Hz. I very much like the look of the spaced triple Mega Traps in the front corners - I'm assuming in order to cover the ceiling corner, as there wasn't enough space for a fourth?

Greetings from Switzerland, David.
 

Dennis Foley

Member
Sep 11, 2019
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Attached is a picture of my current room. I have somewhat randomly dumped some absorbtion panels on the walls. The two panels behind my speakers are 4" bass traps. I will take possesion of a pair of Evolution Acoustics MM3 tomorrow and have sold the two subs in the picture.

http://forum.audiogon.com/cgi-bin/fr.pl?vhome&1285196540

My question is twofold. With the subs gone, I have now space for "top to bottom" triangular corner bass traps behind the speakers. Is this always a good idea, or are (REW or other) measurements required to assess if this will beneficial in my room? Should I set up and measure the new speakers first before spending some money (not soo much), on traps? Note: I also have a Trinnov room correction system to address bass issues.

If I end up buying the corner traps, what would be the best position to put the 24 x 48 panels? The ceiling would be the most obvious location. Apologies for my ignorance - I feel like a true amateur among the pro's hanging around here.
The corners of a room are not the issue. It is the complete wall surface area. By definition, axial modes are produced by two parallel surfaces not two parallel corners. A corner represents only a fraction of the surface area of the total wall.
 
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BruceD

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The corners of a room are not the issue. It is the complete wall surface area. By definition, axial modes are produced by two parallel surfaces not two parallel corners. A corner represents only a fraction of the surface area of the total wall.

Thats interesting--so if the corners are not an issue--can we do anything about these reflections --are they not as evident as shown here?

Appreciate the professional opinion --thank you

BruceD
8392b758-1a6e-485c-8a0d-ed10f2557d2e.jpg
 

Dennis Foley

Member
Sep 11, 2019
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www.acousticfields.com
You have two types of "energy" within your room. You have wave energy which is energy below 100 Hz. You have ray energy which is energy above 100 Hz. Wave energy is pressure based. You must use a pressure based technology in order to adequately treat wave pressure issues. Ray energy which is more reflection based can be treated with technologies that use air flow to absorb the excess energy. Treat the walls with both wave and ray treatment types. If you are concerned with reflections from the corners, treat reflections with the proper technology. A economical treatment type that is predictable and consistent is open celled foam. Make sure you use the proper rate and level of absorption for music and voice. Music and voice are different than noise and have different rates and level absorption requirements.
 
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