Help me with set up issue - soundstage

[sqlkev]

I need some help tuning my system, maybe some pointers from you guys will get me started.

Currently, my speakers are dipole and placed about 3 feet away from the wall. Left and right speakers are about 5-6ft away from each other. The couch is about 10 or 11ft away.

The speakers are now running in dual mono mode with the behringer dcx2496. I've also used the mic to do auto delay alignment and auto polarity. The sound?
Well, I would say the sound is a slightly to the left about 6-12" from the center. It's not too bad, but I can pinpoint the center of the stage being left biased. The stage is also "crunched in" in that area for most of the sound passages. Not much dimensional to it and depth is very limited.
However, on movies, the sound is much more pan out to the sides. For example, when a car goes from left to right. I can hear it comes all the way across the left side of the room and reaches far to the right side as it disappears.
With the system set up in dual mono mode, the speakers seem to disappear, but depth and width somehow seems limited.

Tonight, I switched the dipole back to my first initial set up. Delays on the tweeter a bit more than the mids, both sides are the same. No auto polarity and all drivers in phase.
The sound?
a bit more hollow and has a better depth to it, but the trade is more localization of the speakers and less pinpoint imaging. Somehow I prefer the depth to the music a bit more as it sounds more relaxing.

Can't I have both? pinpoint imaging + depth? The added bonus would be the layering in of musical instruments in the recording and a bit of air.

I really don't want to do room treatments since this is a family living room and we have guests coming over all the times. The living room looks already bad as is with all my stuffs being the centerpiece.

[Nanook]

the exact opposite of what many strive to do without.

first I'd sketch out a picture of your room.

Then I'd suggest that you get rid of all signal processing (just get rid of all or any delays that you have adjusted into the system ,after making notes as to the original settings you now have), except if you need the device to act as a cross over.

make note of all adjustments.

And then if you must, start again. hmmm. "dual mono mode"? Is that exactly what it sounds like? (I'd disable that right away. almost all recordings have cross talk , and rely on it for "soundstage" information -we hear some of this as a localized , solid "image")

I've downloaded the manual and will have a quick read, but I think the key here is to remove as much of the processing as possible.

[sqlkev]

Sorry I wasn't clear,
the dual mono mode is actually referring to my deq2496 doing the EQ individually for the left and right channel. I've left that piece of information out.

Thanks for the suggestion,
I'll need a whole day some time this week to sit down and start from the beginning.

Here I attach a quick sketch of the living room, I've left out the coffee table and miscellaneous small stuffs.

BTW, my entertainment center is more like a low profile audio rack, it's only 16" high or so, and no TV on it.

[nunayafb]

Three potential problems I see:
1. you have a couch on the right and bare wall on the left, this is probably affecting the first reflection to some degree.
Possible solutions- Bookcase, or a thick framed canvas painting with rockwool behind it
2. the first reflection from the left speaker appears to be going mostly down the hallway and not reaching the listeners.
Possible solution- Spread the speakers out and toe them in or just toe them in a little.
3. Kind of the same problem as in 2. you only have a backwall on the right, so any energy on the right will reverb. but the left side will go down the hall and lose alot of amplitude
Possible solution- Same as 2.

Is the delay you are referring to part of an electronic crossover? What other DSP have you applied?
If this is your active crossover have you tried just phase and time alignment of the mid/woofer and tweeter and nothing else?

[Nanook]

do you have actual room dimensions and can you re-arrange the furniture? (I know, WAF and all that , but is it a possibility?).

I see a couple of options if it is a possibility (does she love music?), wher no or minimal processing would be required.

[MBK]

Hi,

I've also noticed similar issues with my dipoles (analog X-O). My room is similar, but my speakers are located on the left side (if it was your room) .

Anyway, what's happening is that as pointed out above already, the asymmetric first reflections influence the panning of the source. We mostly rely on "first arrival" and amplitude response in the higher frequencies for sound localization, so the first reflection (position and absorbance) does most of the work here. Your high frequencies must be reflected more on your left side.

An easy solution is to move both speakers to the right by say, 1 m (centered on your sofa, instead of centered to the left side of it). You increase reflected SPL to the right that way, and shorten and arrival time. Added benefit: some research has shown that asymmetric speaker placement with regards to the room benefits the room modes so you should get better bass envelopment.

As for the trade offs of air and depth vs. pinpoint imaging: much of the "air" and depth comes exactly from the first reflections. If you had no reflections (anechoic) or very late ones (huge hall) you'd be hearing as if wearing headphones, or headphones plus echoes ;-) .

The ranges IIRC are:

- you *don't* want reflections too early (0.5-5 ms, or 17 cm to 1.7 m = 6" to 60" path length difference between direct and reflected sound)). Those would merge with the original image and confuse the soundstage.

- you *want* reflections 10 - 50 ms for air and depth (say 3 - 17 m or 10-60 ft path length difference direct-reflected).

- you *don't* want 50-150 ms path length difference, (hampers speech intelligibility) but that is more of a problem for PA installations in large venues.

Conclusions, as you move your speakers away from boundaries / fiddle with delay and reverb settings, you initially lose image focus but gain air, but at some point you regain image focus while keeping air and depth. For this to happen ideally your delay / path length difference between direct and reflected sound, should be in the 10-50 ms range, or below 1.5 ms, or above 150 ms.

[ruerose]

The room and the 2 couches make it hard for WAF.

I'd ditch the least comfortable couch and just have the one there.

The Loveseat can go in the corner for some Low frequency absorbtion, but will visually look off there.

Also, try treating the front end with some absorbtive wall coverings, might help the imaging come out. I use a large tapestry set off the wall by a couple inches.

[sqlkev]

I love the suggestions gentlemen,


nunayafb

Three potential problems I see:
1. you have a couch on the right and bare wall on the left, this is probably affecting the first reflection to some degree.
Possible solutions- Bookcase, or a thick framed canvas painting with rockwool behind it
2. the first reflection from the left speaker appears to be going mostly down the hallway and not reaching the listeners.
Possible solution- Spread the speakers out and toe them in or just toe them in a little.
3. Kind of the same problem as in 2. you only have a backwall on the right, so any energy on the right will reverb. but the left side will go down the hall and lose alot of amplitude
Possible solution- Same as 2.

Is the delay you are referring to part of an electronic crossover? What other DSP have you applied?
If this is your active crossover have you tried just phase and time alignment of the mid/woofer and tweeter and nothing else?

1. I think i'll try some to put something over that left wall to see if that helps, would a low cabinet works?

2. I've tried toeing in the speakers about 10-15degrees. The sound is very limited to basically 1 spot. It doesn't have the spacious sound that I prefer from the dipole either. I'm thinking it has alot to do with the MTM setup, but I'm not sure.


Nanook
[quote]do you have actual room dimensions and can you re-arrange the furniture? (I know, WAF and all that , but is it a possibility?).

I see a couple of options if it is a possibility (does she love music?), wher no or minimal processing would be required.

The room probably about 14'x19', moving the furniture around is a possibility if it really helps with the sound. The thing I really have to consider is the projector's pull down screen. As of right now, it's hanging over the fireplace (where the audio rack is at). If I were to move it anywhere else, I'd have to find a way to hang the screen securely.

MBK
that is a really interesting read on acoustics. As for the speaker placement, I can't really move more to the right. The projector's screen is right above the audio rack. and that's where the fireplace is. Moving the screen to the right 1 meter would be a difficult task, since i have to rig up something to attach the screen to.


Upon reading your response, I think this living room doesn't really work out for me.
We have a dining room that might work better. I'll draw up a quick sketch tomorrow and please give me some feedback on it. (been driving 8 hours today and my mind is numb )


ruerose,
that diagram doesn't really work for me. The right wall is actually the patio door (it's closed whenever I listen to music and has a rather thick drape to absorb some of the sound)

[Nanook]

I did this in AutoCad using 14'X19' dimensions, and typical 2 and 3 seater sofa sizes., first and second reflections are drawn, as are possible "fixes", a book case and a new chair for fireside reading ...:-)

the primary sound crosses in front of the "sweet spot" so that the sound is better for all watchin video...guess I didn't realize this was a HT thing, sorry.

[inertial]

Hi sglkev,

IMHO the wall behind your listening position is one of the issues.
You can try a big absorber( like fiberglass or similar) behind your head.
Imho a good surface is required ( 4 feet x2- 2,5 ) and a good thick also
(6- 8 inch if possible). Experimentations can help, I hope.

Cheers,
Inertial