Square room horror

[ZolaIII]

It doesn't do much as the peak is there even when you don't play anything (in environmental noise) and neither will acoustic absorbers when it's that low. I have one at 43~46 Hz. Experimented with absorbers, closed enclosure speakers and subs which did help make it less prominent but it didn't disappear nor it ever will. When you combine all bit by bit you menage to get it better and ideal doesn't exist. At least that's my experience.

 

[Holdt]

It doesn't do much as the peak is there even when you don't play anything (in environmental noise) and neither will acoustic absorbers when it's that low. I have one at 43~46 Hz. Experimented with absorbers, closed enclosure speakers and subs which did help make it less prominent but it didn't disappear nor it ever will. When you combine all bit by bit you menage to get it better and ideal doesn't exist. At least that's my experience.

Well I'm sorry you haven't had luck getting rid of yours. I'm well aware of my room modes and I have integrated and tamed my subwoofer just fine using Dirac and before that REW constructed EQ.

And if I don't activate the mode with any sound it's not there (It's not a problem). When EQ'ing the 31 Hz peak down some 15 dB or so (can't remember) then it cuts -15 dB at any given volume to match the rest of the response, hence flattening it, effectively eliminating the room mode. Some nulls are different beasts though. I don't boost very much in my EQ.

 

[audiofooled]

Hi guys

Thanks for all the input - it's very much appreciated.

1. Sorry, will post pictures of the room when I can. Don't have any to hand. There's a stone fireplace to the left of the room and a sort of stone alcove/shelf extending into the room near to the left speaker in the picture.

2. A second sub is a possibility once my new AVR arrives, as it supports dual subs. AVR is a Yamaha RX-V6A. I know YPAO is not always very highly thought of, but I also have a UMIK-1 and I believe the AVR allows for tinkering with the PEQ manually to some extent.

3. The speakers are Focal Aria 906, front-ported. I ended up with the placement so close to the wall based partially on the results of REW sim, but also the suggestions (link below) which you may have already seen around the web. I'm not averse to trying them in a different position, though! The sub is a wallet-friendly Polk PSW10.

The #1 Speaker Placement Tip That Speaker Manuals Get Completely Wrong — SonicScoop

Speaker placement tip #1: it’s not enough to simply set up your speakers in an equilateral triangle and be done with it.

sonicscoop.com

Here you can see an interactive view of your room behavior (not so different from your REW simulation) https://amcoustics.com/tools/amroc?l=400&w=400&h=210&r60=0.6

Further more, from what I can see in Amir's review of Focal 906 https://www.audiosciencereview.com/forum/index.php?threads/focal-aria-906-speaker-review.14085/

and from response of Polk PSW10 that Erin had measured in his 10 inch subwoofer showdown, I can see that both speakers and a sub are peaking around 60 Hz. And all of them are front ported. This too has to be taken into account for good integration and to avoid phase cancelation issues. You can try moving the speakers away from the wall a bit to avoid SBIR problems and to less excite first order mode of 43 Hz. Also, try placing the speakers equilaterally at 25% distance from the left and right wall to avoid further exciting the 60 Hz mode which is peaking in the room corners and could produce unwanted ringing and muddying of the bass. In your case, the vertical centers of each speaker should be about 1m away from the left/right wall, which sets them about 2m apart. Then play with toe in with respect to your listening position.

As for the sub, you can keep it in the middle between the speakers but fairly close in line with them because of the ports and modal issues. Then you can play around with plugging the ports of the speakers or preferably that of a sub and crossover/DSP to get a more even response (82 Hz peak is excited more due to the sub being close to the floor, so EQ may help bringing this down). The listening position should not be too close to the rear wall.

I also always recommend this thread https://www.audiosciencereview.com/forum/index.php?threads/analytical-analysis-room-gain.23211/ about differences between room interaction of sealed and ported subs.

And this example from Dr. Toole's book (option d for your speakers). I hope you find this helpful.

 

[krabapple]

It doesn't hurt being repeated

"Alternately, put two subs (fed the same content) on front wall at 1/4" width positions, and sit ~2/3-3/4 of the room length from the front wall, centered between the left and right walls....[as Floyd Toole noted]"

And who would have guessed that the dastardly corporate shill Floyd Toole would promote such useful advice?

 

[Descartes]

It doesn't hurt being repeated

"Alternately, put two subs (fed the same content) on front wall at 1/4" width positions, and sit ~2/3-3/4 of the room length from the front wall, centered between the left and right walls....[as Floyd Toole noted]"

And who would have guessed that the dastardly corporate shill Floyd Toole would promote such useful advice?

What is the page number!
Just bought the newest version of his book it is on sale at Amazon! Had the previous version on the bookshelves already.

 

[Descartes]

My second system is in a square room of barely larger dimensions than your room and I have enjoyed it for years. However, the room has a fair amount of acoustical treatment, the system always employs DSP-based roomEQ, there are multiple subs and it is a multichannel system (either 5.1 or 5.1.4). All of those contribute to the taming of the acoustics.

How many subs?

 

[Kal Rubinson]

How many subs?

3

 

[krabapple]

What is the page number!
Just bought the newest version of his book it is on sale at Amazon! Had the previous version on the bookshelves already.

The mode cancellation image I linked to is not from his book, but from a white paper. But audiofooled's post #43 above shows a clearer image of the same thing and it shows as being from Fig 13.11 , page 221 of the 1st or 2nd ed. of Sound Reproduction. In the 3d edition e-book , it is figure 8.13 (page 237-8 of 490). I don't have my 3rd ed. hard copy (yes I have both book and e-book!) handy so I can't provide a physical page reference right now, sorry.

 

[Descartes]

So I am confused the conclusion on the slide shows 2 subs front and back?

But you show two subs in the front so which one is better?

 

[krabapple]

So I am confused the conclusion on the slide shows 2 subs front and back?

But you show two subs in the front so which one is better?

View attachment 259201

The Welti work in your image has a different focus. Its goal is to minimized variation in perceived bass response over a range of seats.
The method I showed you is for cancelling the three primary width modes at one seat , located in the midline of a rectangular room.

You should dig into Toole's book where it discusses these subjects. Welti's paper is also freely available IIRC, or at least, i seem to recall someone posting a PDF link to it on this forum.

 

[Jim Taylor]

Welti's paper is also freely available IIRC, or at least, i seem to recall someone posting a PDF link to it on this forum.

It doesn't hurt being repeated:

https://www.harman.com/documents/multsubs_0.pdf

Jim

 

[Digby]

Or at least a combination. Treat as much as feasible given WAF etc.

If you treat the W, AF may increase (this is never guaranteed!), making it possible to add more treatment to the room too.