Never Put Subwoofers In Corners... Even with DSP and Multi-Sub Setups?

[RichB]

Cheap from ex cinema cheap than fish and chips. JBL 4645C - a homemade 4645 behind the flat screen.

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Sooty looks at JBL 4645 wants to climb in though the port like when he was a kitten.
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The new litter box.

- Rich

 

[burningyen]

Hi all, first-time poster here, but I've been reading avidly for the past few months as I've been setting up my home studio. I'm trying to refine my speaker placement (two Neumann KH80s and a Dynaudio 9S sub) before committing to room treatments and EQ. The room is 21'7" (L) x 11'10" (W) x 6'11" (H), and my listening position is fixed at about 4' from the center of the front 11'10" wall. So placement of the KH80s is also fairly fixed, but I have options as to sub placement. I've currently got it under my desk at the center of the front wall, which results in a pretty nasty room mode peak at 26Hz and 71Hz null at the listening position:

The 26Hz peak worries me the most because I'm not finding many practical room treatments for that. Playing with the Room Simulator in REW, I've learned that any sub position along the front or back walls leaves that 26Hz peak intact:

But putting the sub somewhere between the front and back walls starts to flatten out that peak. Most interestingly, putting the sub in the exact center of the room provides the flattest response below 50Hz and moves the peaks and dips above 50Hz, where I'm guessing room treatments will be more effective:

Conveniently, I was planning to put a coffee table in that center location and could easily fit the sub under it. Am I missing something as to why this sub placement is a bad idea?

 

[stevenswall]

^Do you have a MiniDSP or some way of applying EQ? If so, don't worry about the peaks, they are easy to fix.

Sub placement wise I always have issues with nulls and flabby response, and the best I've heard it putting them behind my seating position, but I swear you can localize them.

Generally, if a sub sounds good and measures well in the listening area, the placement isn't bad. I'd love to be able to fit a sub under another piece of furniture. Go for it.

 

[dasdoing]

I've currently got it under my desk at the center of the front wall, which results in a pretty nasty room mode peak at 26Hz and 71Hz null at the listening position

try turning it 180 degrees....as close to the wall as it gets

 

[burningyen]

^Do you have a MiniDSP or some way of applying EQ? If so, don't worry about the peaks, they are easy to fix.

Not yet, and honestly I'm a little leery of any digital solution. I'll be recording and monitoring guitar and other electric and electronic instruments through this system, and any latency could throw off the feel. I'm also not seeing a miniDSP-type box that will integrate well with an XLR-based system.

Sub placement wise I always have issues with nulls and flabby response, and the best I've heard it putting them behind my seating position, but I swear you can localize them.

Generally, if a sub sounds good and measures well in the listening area, the placement isn't bad. I'd love to be able to fit a sub under another piece of furniture. Go for it.

Thanks for enabling!

 

[burningyen]

try turning it 180 degrees....as close to the wall as it gets

Thanks for the suggestion. I'll give it a shot, but in REW's Room Simulator moving the sub to within inches of the wall doesn't seem to change the 26Hz peak. And given how nondirectional subs are I'd be surprised if it did have an effect.

 

[sigbergaudio]

Not yet, and honestly I'm a little leery of any digital solution. I'll be recording and monitoring guitar and other electric and electronic instruments through this system, and any latency could throw off the feel. I'm also not seeing a miniDSP-type box that will integrate well with an XLR-based system.
Thanks for enabling!

"Why on earth didn't I get EQ for my system before?" <- this is you after you've installed some kind of EQ solution and applied EQ to the lower frequencies.

 

[dasdoing]

Thanks for the suggestion. I'll give it a shot, but in REW's Room Simulator moving the sub to within inches of the wall doesn't seem to change the 26Hz peak. And given how nondirectional subs are I'd be surprised if it did have an effect.

it should remove the speaker boundary interference dips.

placement wont solve the 26Hz issue. it's a longitudinal mode. absorb at the backwall

 

[Chromatischism]

Large peaks are fine as EQ can knock them down. It's actually good sign that you picked up a large amount of efficiency there. Just find a location that eliminates the most dips.

 

[onion]

Shame - Acoustics Fields Guy is doubling down on his anti-multi-subs campaign. I don't think this is smart marketing

 

[dasdoing]

Large peaks are fine as EQ can knock them down

look at the huge tail on the spectrogram. you can't eq that out

 

[Bear123]

look at the huge tail on the spectrogram. you can't eq that out

Actually, when you eq that peak in the response down, won't the spectrogam drastically improve in that region as well? That has been my experience. The spectrogram looks that way precisely because of the room mode before eq.

 

[Harmonie]

Shame - Acoustics Fields Guy is doubling down on his anti-multi-subs campaign. I don't think this is smart marketing/ .

I didn't notice any anti-multi-sub campaign in that video.
On the contrary, he says very sensible things.
True that he is anti-Boom Boom, like having 2 x 15" in the back of your car ...
He is rather fan of good sounding bass.

What he DOES refrain is you to add bass in

 

[dasdoing]

Actually, when you eq that peak in the response down, won't the spectrogam drastically improve in that region as well? That has been my experience. The spectrogram looks that way precisely because of the room mode before eq.

it sure will, but the tail wont disapear.

personaly I like the "normalize to peak at each frequency" option, because it shows the real ringing.
here is my room (l) before and after EQ.
the 40Hz-ish ringing is what most "hurts" my ears in my setup when a note hits it

 

[Puddingbuks]

it sure will, but the tail wont disapear.

personaly I like the "normalize to peak at each frequency" option, because it shows the real ringing.
here is my room (l) before and after EQ.
the 40Hz-ish ringing is what most "hurts" my ears in my setup when a note hits it

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Am I right considering “bass trapping”, as in reducing the reverberation time (with lots of absorption) of the room and also in low frequencies, is just as important as fixing room modes with subwoofer placement or EQ?

 

[sigbergaudio]

Am I right considering “bass trapping”, as in reducing the reverberation time (with lots of absorption) of the room and also in low frequencies, is just as important as fixing room modes with subwoofer placement or EQ?

Short answer : No. Partly because (as already mentioned) it's practically impossible in most domestic situations. And partly because you get a very long way without it.

Reducing the reverbation time in the frequencies above low frequencies on the other hand, is both possible and very desirable.

 

[sarumbear]

Short answer : No. Partly because (as already mentioned) it's practically impossible in most domestic situations. And partly because you get a very long way without it.

I don’t understand this logic of bass traps not suitable in domestics situations but having three or four large subwoofers is suitable. Floor area is the limiting factor in a room. You price a house by the area. Bass traps often occupy less floor area than a sub.

 

[sigbergaudio]

I don’t understand this logic of bass traps not suitable in domestics situations but having three or four large subwoofers is suitable. Floor area is the limiting factor in a room. You price a house by the area. Bass traps often occupy less floor area than a sub.

But you don't need a couple of bass traps, you need like eight plus a wall covered in three feet of insulation.

 

[sarumbear]

But you don't need a couple of bass traps, you need like eight plus a wall covered in three feet of insulation.

How can you know that without knowing how the room behaves?

Besides, what has insulation to do with acoustic treatment?

 

[sigbergaudio]

How can you know that without knowing how the room behaves?

Besides, what has insulation to do with acoustic treatment?

A false wall that is open to insulation is a very effective way to create a hidden bass trap.

I don't know exactly what you need specifically, but I'd be very interested to see a bass trap that doesn't take up more floor space than an additional sub, and does just as good a job as an additional sub of evening out the response below 100hz.