Long or short wall?

[mark3141]

Hi,

First, let me know if this should go in a different sub-forum, and I'll be happy to move it.

I was hoping to get some feedback on whether to set up my speakers parallel to the long or short wall in my listening space. I know I could just move them around to see what sounds best, but I will be treating the room and so I'm really wanting to know which is likely to be best after treatment. Second, what affect would adding a large TV have centered between the speakers have? Would covering the TV in a thick blanket when listening help or alleviate most of those concerns?

The problem is that the room is rather unusual with so many openings (pictures here - Basement - Google Photos). The long wall runs 24', and it is 13' across the short wall.

More than happy to answer any further questions and can edit/update this post as needed. If necessary for this question, here's my current gear:

Equipment:
Speakers: Usher S-520/SW-520
Power Amp: Currently playing around w/ two but ultimately with bi/tri-amp my speakers - B&K ST2140 and NAD C-245BEE
Pre-Amp: Antique Sound Lab Line one DT
DAC: Cambridge DACMagic

Thanks!

 

[AllenB]

Along the short wall you may have sides close to the speakers. Along the long wall you may have the back wall close to the listening position. Each will give an early reflection but from a different diection. I like to use the short wall with directive speakers.

The TV will have an effect, but it may not be easy to tell (you might not even notice depending on how you do it). Speakers with helpful baffles can help here too.

 

[mark3141]

Dumb question, but what are the baffles you mention?

But since the room opens up on large portions of the back wall, would that alleviate some of the rear wall issues? Also, is it likely proper treatment would mean either option will be largely the same?

Glad to know a tv won't be a huge issue. I've noticed most seem to put treatment between the speakers on the wall behind the speakers presumably to deal with those reflections. Is that overkill or is the TV acting like a diffuser of some sort?

 

[JeffYoung]

Short wall is generally recommended. That being said, I have mine on the long wall because it suits my listening position better.

 

[scottjoplin]

Diagonally can be better than either

 

[mark3141]

How would the diagonal set up look? Depending on the level of improvement, I might forgo that option if it undermines the room's use for other things.

 

[scottjoplin]

It can work practically http://www.wghwoodworking.com/audio/UnderstandingRoomAcousticsAndSpeakerPlacement.pdf

 

[AllenB]

what are the baffles you mention?

A baffle should take control or relinquish control gracefully, normally both. There is obviously no benefit in spraying the TV. Since this is an involved topic, you could also create space between the speakers and interfering items, and move the TV back away from them as higher frequencies tend to be more concentrated toward the front.

But since the room opens up on large portions of the back wall, would that alleviate some of the rear wall issues?

Possibly. Trace the reflection paths and see. Bass and treble room issues are quite different in nature.

is it likely proper treatment would mean either option will be largely the same?

Possibly yes. A directivity controlled speaker can also achieve this.

Glad to know a tv won't be a huge issue. I've noticed most seem to put treatment between the speakers on the wall behind the speakers presumably to deal with those reflections. Is that overkill or is the TV acting like a diffuser of some sort?

I once had a 4' fish tank between a pair of conventional floorstanding box speakers and when I moved it, I could hear the absence of the 'shadow' of the tank, like an audible silouhette. It wasn't that it was objectionable, I was surprised that I could clearly hear it.

 

[GM]

I was hoping to get some feedback on whether to set up my speakers parallel to the long or short wall in my listening space.

Second, what affect would adding a large TV have centered between the speakers have? Would covering the TV in a thick blanket when listening help or alleviate most of those concerns?

The problem is that the room is rather unusual with so many openings (pictures here - Basement - Google Photos). The long wall runs 24', and it is 13' across the short wall.

Based on the pics, diagonal to break up the room modes as much as practical due to all the coupled cavities that will impact the basic modes. The basement layout reminds me of a poorly designed Karlson K15 cab in concept.

Depends on how close the TV is to them, though in such rooms as yours, some form of waveguide/horn system from at least 900-1200 Hz-up [the lower the better IME, 500 Hz in my case] combined with toe-in is desirable regardless of speaker/room orientation to 'focus' the sound enough to keep early reflections from occurring until behind the listener's ears. That, or copious panel absorbers between the speakers, TV and any other large surfaces.

GM

 

[mark3141]

Thanks for all the input. I decided against the TV (just too much trouble) and tried the diagonal approach which sounds much better. Given the geometry of such a placement, I tried to find a position that allows me to get the speakers as far away from the walls as possible. This lead to my seat being right next to the ~1' column that opens into the little alcove there which probably isn't ideal, but with treatment, I'm hoping it won't be too bad.

Are there any rules of thumb for speaker placement when you're working along the diagonal, though? I know there isn't one option that always works best, but since there are so many possible options, I'd like to limit my comparisons between at most three general positions and then tweak from there.

Now that I'm happy with the diagonal, next steps are to tweak the positions and use something like REW to measure and figure out room treatment options, but I'm happy to listen to other thoughts if I'm missing something.

 

[GM]

The THX cinema's 60 deg [included] angle determined for the original three channel stereo is the starting point and usually fine once proper toe-in is found [if required] and of course any room treatment required to ideally keep the upper mids, treble early reflections to behind the listening position.

GM

 

[mark3141]

Do you mean that if your listening position is the apex, the left and right speakers form a 60 degree angle? That's how I have them set-up, and is the same as saying the speakers and listener are all equi-distant. That still leaves a lot of options which are determined by how far you come off from each wall. Is this as important as it is when you set your speakers parallel to the wall?

 

[GM]

thx cinema layout - Google Search

I see that in recent years they've changed to a range, but 30 deg offset [60 deg included] is still the limit for a phantom center channel [CC].

GM

 

[graaf]

Long or short wall?

neither

try side-wall positioning - "Beveridge placement"

 

[norman bates]

I read diagonal was best, but my setup is just 1 speaker under tv for now and sub.

DECWARE - Article about Setting up a Listening Room without Treatments

I had luck with long wall setup with sonotube on side brick walls.
Based on that, I'd cover every wall with them if i could.

ACS Articles - The Sono Tube Fix!

 

[graaf]

a handy tool: http://www.linkwitzlab.com/LX521/Dipole%20First%20Room%20Reflections%20SL%20rev4-b.xls

"James Heddle contributed a spreadsheet, which calculates the strength and delay of first order room reflections."

Listening_room

In side-wall "Beveridge" placement one has just to treat the wall near the speakers, then this method of speaker placement is the clear winner.