3D stereo sound with 4 speakers + room correction


Hi all,
I´m Johnny - a long time reader of Audiogon, hifi geek and music producer from Denmark - and I have a "different" question to all of you Audiogoner´s out there.
Have anyone tried to do a stereo system - but with 4 speakers and room correction + time alignment? Fx 4 (same) speakers to 4 monoblocks or 2 power amps from a preamp + room correction. Maybe you´ve just tried with 4 speakers and no room correction - anyways - let me hear your experiences.
I´m thinking of - sometime in the future - if funds and space allows it - to do a system like that. I would put 2 speakers as fronts and 2 speakers as side speakers. I imagine that the room correction and time alignment would make it possible to achieve a 3D stereo sound that reaches your sweetspot at the same time - but still in stereo. The sound stage would be almost all around you and massive.
Is this completely nonsense or would it make sense to do a system like this?
Ps. If I had the money - I´m thinking - Soundlab U1 speakers + 2 or 4 JL Audio f113 subwoofers and some great amplification + source. We don´t have Soundlab speakers here in Denmark so I have yet to discover the sound of them - though I have heard both the biggest Magnepans and Martin Logans - and several other high end speakers incl. MBL (the big ones) Adam (reference setup) Avantgarde (the big system). My own speaker are Audio Physic Scorpio - and I´m actually very pleased with them and I will keep them for a while.
Please let me know your thoughts on my question.
ps. and thanks for letting me dream away in the member systems pages :-)

Regards
Johnny
Denmark
js1973
Johnny,
Please take a look at this website for some insight on what has been done and tried in this realm:

http://www.ambiophonics.org

Hi Johnny

The idea is interesting and time alignment will be important. How do you plan on achieving the room correction part to the sound?

I almost think you are talking about crosstalk cancellation to achieve room correction?

Just trying to see where we are going with the idea thats all, its very interesting to me as I always thought to achieve the concert hall sound it would require one to start with two pairs of identical speakers but never experimented with this theory.

Ed
Hi Carlos and Ed.

Thanks for your responses.

@ Carlos - very interesting link to the Ambiophonics page - I will read more into it during the weekend. I see that Tact is doing a device to provide concert hall "feeling". They are also known for doing good digital room correction.

@ Ed - For the room/time correction part I would use digital room correction - like provided by Tact http://www.tactlab.com/DRC/drc.html or similar. There will be loads of those products from different companies in the future - I´m sure :-) And I also know that it´s getting more popular in music production - with good results.
I´m not sure what crosstalk cancellation means in english - sorry? My father though has a setup with 4 speakers - BUT - he kind of blew it regarding stereo perspective - since he has connected the speakers to a receiver that only lets him connect to left and right - respectively. Which means that when he´s in the middle of the room he has to face one of the speaker sets to get real stereo - and the other set in the back of his head - is kinda in the wrong phase I guess.
Well he doesnt care to much about since he´s not a sound freak - good for him ;-).
If room correction - and more important the time and phase is done correct by some digital unit - fx the the link to the page Carlos gave us - I´m sure it could be a great experience - but I´m not sure if we should have the extra pair of speakers on the side or in the back.

Johnny
Did a bit more reading on this site:
http://www.ambiophonics.org

Very interesting.
Johnny
Hi again Ed,

Now I know what you mean by cross talk cancellation.
With english not being my native language it´s sometimes a bit confusing. ;-)

Regards
Johnny
Hi Johhny. Does the TACT allow you to connect four amps & speakers in the manner you are talking about? I would think all four speakers would need to be facing you to be in alignment with each other and your sitting position. It would be an interesting experiment but will cost a few $ to pull off if you want to use identical high end amps & speakers. Also bass response is an issue. Four speakers in the same room may actually cause bass waves to cancel each other leaving a thinner bottom end. I would seem to think the processor you choose will need to try & correct so many room & audio anomalies that the music recorded and mixed to two channel will become very artificial sounding.
I'm using quite a high-end four speaker arrangement at the moment, with no room correction and frankly the sound is pretty amazing (fuller, richer and more 'scary' good than with just the two channels).

Speakeers in front are Audio Physic Avanti III, rears are German Physiks HRS-120; I have them at the rear because they are omni-directional and so are easier to place and seem better able to produce that ambience. I'm likely selling the German Physiks as I had felt I only need one pair of speakers and they seem a bit of an extravagence having speakers costing over $30k for rears ;-) But, I'm loving the experience. When I do a/b comparison, it's just so much better with the four speakers. I think the key is having omni directional at the rear which fit in and disappear much better, even without room correction. My 2-cents; maybe it's not supposed to sound better, but believe me, it does.