OK, I'll give that a try and let you know. I was only doing it in software because it's faster and easier for me to do it that way.
It seems to me that the bloating of the central images, that can arise when the speakers are placed more than 30 degrees (or so) apart, is the biggest problem with the reproduction of conventional two channel stereo recordings. If so, I have been wondering why the general response to this thread has been somewhat muted, (Pano excepted)? However, whatever the reason, I am thinking of offering a free Stereo Field Unit to the first three site members, or moderators, who request one. Note: All units would be hand made prototypes that have no intrinsic value and come with no guarantee that they are free from intermittent faults (e.g. dry joints). 😉 Would anyone be interested?
jedaisoul,
I'd be interested in testing your stereo field unit, but I'm in the USA.
Personally, I think the muted response to the thread may be due to the fact that matrix solutions have gotten significantly better over the last 20 years, and many people cannot fully realize the benefits of passive processing since other parts of their systems (source file or streaming/DAC/amp/eq/crossover) already contain the same drawbacks to any matrix solution (smear, transient decoherence, decimation, compression, ringing, etc) and so the benefits to a passive system just are not realized for most people.
bob
I'd be interested in testing your stereo field unit, but I'm in the USA.
Personally, I think the muted response to the thread may be due to the fact that matrix solutions have gotten significantly better over the last 20 years, and many people cannot fully realize the benefits of passive processing since other parts of their systems (source file or streaming/DAC/amp/eq/crossover) already contain the same drawbacks to any matrix solution (smear, transient decoherence, decimation, compression, ringing, etc) and so the benefits to a passive system just are not realized for most people.
bob
It may also be muted in response because overall it's more speaker related than line level, although it doesn't fall neatly into a single category.
And of course it's unusual and different. It might take time to get it rolling.
And of course it's unusual and different. It might take time to get it rolling.
Pano
bobthedespot
Thanks for the comments. I'm not sure how to sustain interest in the system. I'm not by nature a gregarious person, nor an entrepreneur. I'm an ideas man. I'm also 71 years old and in poor health. I'm concerned that interest in this setup will just fizzle out, which would be a pity. Its a simple idea, but it works.
Would getting a working party together to take it forwards be the answer? I'd gladly hand over my designs for the Stereo Field units, though, as you know, you don't really need one. But they do add functionality.
Bob: I'll see about building a unit for you. I'll keep it small and light weight, to minimise the postage, but I need some info:
1. What kit do you have (or intend to get)? E.g. AV 5.1, 7.1 or non-AV 4.0 or 6.0 etc...
2. Do you know the make, model and input impedance of the power amp?
bobthedespot
Thanks for the comments. I'm not sure how to sustain interest in the system. I'm not by nature a gregarious person, nor an entrepreneur. I'm an ideas man. I'm also 71 years old and in poor health. I'm concerned that interest in this setup will just fizzle out, which would be a pity. Its a simple idea, but it works.
Would getting a working party together to take it forwards be the answer? I'd gladly hand over my designs for the Stereo Field units, though, as you know, you don't really need one. But they do add functionality.
Bob: I'll see about building a unit for you. I'll keep it small and light weight, to minimise the postage, but I need some info:
1. What kit do you have (or intend to get)? E.g. AV 5.1, 7.1 or non-AV 4.0 or 6.0 etc...
2. Do you know the make, model and input impedance of the power amp?
@jedaisoul, seems like an deceptively simple concept.
Initially, I thought you were about to describe either, the old David Hafler matrix- which is a passive L-R ambience extraction method, or some inter-aural crosstalk cancellation circuit- such as Carver's old Sonic Holography circuit (Polk Speakers has long sold a passive version of that which they branded, Stereo Dimensional Array or SDA). Or, perhaps, the old Joel Cohen of Sound Concepts version circuit. I find that such simple approaches have to be heard to be fully appreciated. Especially, I would imagine, that's true of your approach because it doesn't create any additional signals at all, only utilizes additional speakers with a stereo feed.
Perhaps, one reason for the slow response to your concept is that many of us aren't set up for multi-speaker music reproduction. For example, I have a multi-channel theater surround set-up in my family room, but it is a very modest system for reasons of domestic and economic practicality. I have a separate dedicated 'audiophile' two-channel music only system in another space. My theater system is not suitable for serious music listening.
Initially, I thought you were about to describe either, the old David Hafler matrix- which is a passive L-R ambience extraction method, or some inter-aural crosstalk cancellation circuit- such as Carver's old Sonic Holography circuit (Polk Speakers has long sold a passive version of that which they branded, Stereo Dimensional Array or SDA). Or, perhaps, the old Joel Cohen of Sound Concepts version circuit. I find that such simple approaches have to be heard to be fully appreciated. Especially, I would imagine, that's true of your approach because it doesn't create any additional signals at all, only utilizes additional speakers with a stereo feed.
Perhaps, one reason for the slow response to your concept is that many of us aren't set up for multi-speaker music reproduction. For example, I have a multi-channel theater surround set-up in my family room, but it is a very modest system for reasons of domestic and economic practicality. I have a separate dedicated 'audiophile' two-channel music only system in another space. My theater system is not suitable for serious music listening.
Ken has hit upon the main obstacle, not many of us can do this setup. I also believe it is somewhat misnamed. Isn't it rather Multi-Speaker reproduction conventional stereo recordings rather than Multi Channel? Of course multiple channels can be used to drive the speakers, but it's still just a stereo signal with amplitude shading.
For me the term Multi-Speaker describes it better.
For me the term Multi-Speaker describes it better.
FWIW, I think that this summer I will build this setup into the wall off my cabin. It should be fun to hear.
Back when I had a room large enough to allow this I didn't have this problem.
I can see 3 issues
1. Many of us have enough of a problem getting 2 decent speakers into our living rooms. 6 would be impossible even if SWMBO allowed it. The SME listening room used to have an unfeasible number of QUAD ESL57s in but it was huge and dedicated to one purpose
2. There are a lot of full surround recordings available now and no one really bothers with them so the general level of interest is low.
3. For those who have looked at different stereo enhancement systems you often hit a problem that different microphone techniques behave differently to processing.
Nonetheless fascinating to consider new ways to drag a better illusion from a 2 channel source.
Issue 4: feeding the same source material to multiple speakers has risk of cancellation at certain frequencies, depending on the speakers' and listener's relative position.
I found it to be a problem, you have to be careful with spacing not to cancel bass. And of course there is comb filtering, just like with 2 speakers. In practice that that doesn't seem too bad, but it could alter tonal balance.
This is an interesting article on "comb filtering" Comb Filtering, Acoustical Interference, & Power Response in Loudspeakers | Audioholics
Pano
Ken
Billshurv
More replies to follow...
Agreed. Thanks.
Ken
Agreed.
Billshurv
This is not a "stereo enhancement system". There is no processing. Instead, it relies on a common element in most professional recordings: the use of a mixing desk and pan pots. These encode the position of acoustic sources as differing voltage levels in the two channels. Those levels fed to two (or more) speakers are combined by our hearing mechanism as virtual sources between the speakers. The mechanism is the same whether there are two, four or six speakers. What differs is that the wider spread of the virtual images can be more revealing. However, I do not see that as being a shortcoming.
More replies to follow...
And this is where we diverge. I'm willing to compromise pan potted synthetic soundfields if I can optimise for the (albeit limited) recordings with minimal microphones. On good classical recordings the stereo illusion is good enough for the tympani to appear to be 6ft to the left and similar back. Mind tricks of course, but a nice illusion.
And I also appreciate I am an outlier.
Ken Newton
Ken Newton
billshurv
Pano
Multi-stereo is not intended to replace, or co-exist, with home theatre. They can use similar equipment, but they use it differently. However, it might be worthwhile to temporarily re-configure a home cinema system, just to test the multi-stereo concept, before committing to purchasing additional speakers etc. for your audio system.
Ken Newton
billshurv
I accept that there are practical issues. However, please bear in mind that there is a four speaker alternative, which has the added benefit that there is no 3dB level imbalance between the speakers. Indeed, loudspeaker impedances permitting, a two channel amp could be used with two speakers connected in parallel to each power amp output. This is not ideal, as it does not allow any adjustment of the "focus" of the system, but it may allow an incremental approach...
Pano
Where there is a will...
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Note: Connecting speakers in parallel can trigger protection systems in the power amp, or PERMANENTLY DAMAGE THE AMPLIFIER. You do so at your own risk. Please ensure that the loudspeakers' impedance is at least twice the minimum load advised by the amp's manufacturer.
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Note: Connecting speakers in parallel can trigger protection systems in the power amp, or PERMANENTLY DAMAGE THE AMPLIFIER. You do so at your own risk. Please ensure that the loudspeakers' impedance is at least twice the minimum load advised by the amp's manufacturer.
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billshurv
I do not see this as a choice. It is a matter of fact that this is the way that the vast majority of stereo recordings have been mixed AFAIK. In any case, I have a recording of the Yeomen of the Guard where the bell tolling is clearly in the distance, and one of the King's College organ that is cavernous. And then there is the extended intro to "Follow Me Home" (Dire Straits - Communique) where the ship bells and the surf have clearly been recorded and mixed in stereo, whilst "Angel of Mercy" (same album) hits you with a wall of sound.