The mistake armchair speaker snobs make too often

@mijostyn

Quadraphonic died rapidly because the technology at the time could not do it without marked compromise in 2 channel performance.

Today you can get a Jim Fosgate designed 4 channel upmixing matrix in a tube preamp (Black Ice F360) that markedly improves 2 channel performance, see this video:

https://youtu.be/noe6GsyYDJc

Even now that the technology exists to do "surround sound" well, people interested in the highest levels of performance regard it strictly as a theater stunt.

"Surround sound" is so last decade, today surround sound has been superseded by immersive audio. News about this in the pro community can be seen here:

https://www.mixonline.com/tag/atmos

If you have decent ears I can prove to you in a very short period of time that a center channel detracts from 2 channel image formation at its highest level.

I just had my hearing tested and its perfect so I’m "all ears". I own a fantastic two channel preamp ( the Sony TAZH1-ES) and if you look at the two channel measurements of my room (posted) it reproduces the two channel response curve I prefer in an exemplary fashion (maybe better than yours? Please post your in room FR to compare if you dare). Let me know your experiment and I’ll do it, then I’ll post an experiment for you as a follow up, fair?

you still have to spend quite a bit more than most people are willing to spend.

This is a deal breaker that actually proves my point, trying to create the illusion of a live music performance with just two speakers is a fools errand. See how the goal posts have moved and artists are now using the same tech I use in my media room to deliver immersive sound to every seat in 5000 seat venues (hint, it needs more than 2 speakers LOL). You can build a system to reproduce immersive audio in someones home for less than $10K. You can blow it out as a SOA system for far less than it takes to build a stereo SOA system (I think the OP has invested over 6 figures if I’m not mistaken and I can’t imagine the time it takes to DIY it):

https://www.mixonline.com/live-sound/venues/on-the-cover-las-vegas-takes-immersive-live-part-1

@fleschler 

Activated charcoal bass filtering? Exactly how are you implementing this?  

@kota1 ,

I think my definition of imaging is different than Mr Clearmountain's. With what he is trying to achieve he is correct. A center channel will improve the results. It will provide the best two dimensional image for the largest number of people (locations), a wide "sweet Spot." I am looking (listening) for something different. A center channel interferes with the formation of the third dimension. People talk about the third dimension even though systems that will produce it are rare, very rare. In my own experience since the early 60's only four systems have achieved this level of performance. The first one was the system of a high school music teacher in an apartment in Coral Gables just South of Miami, FL in 1978. It was based on Sequerra Metronome 2+2W loudspeakers and Threshold electronics in an irregularly shaped room with blankets and bean bag chairs tossed haphazardly throughout. To say I was in awe is an understatement. The second was an HQD system at Sound Components in Miami shortly thereafter. Peter McGrath ended the listening session by frying a Quad with an organ piece trying to impress a customer with the bass performance. Not me! I was not qualified for such a system.  I was in awe nonetheless. It took me another 15 years to get my own system to perform at that level and another 10 years to fully understand what I was doing. #4 is the system of a friend that is relatively modest it relies 75% on DSP to achieve these results. I am working with another friend on a 5th system based on Magico S7 loudspeakers. 

I have said this in other posts, experience is king. You have to hear this to understand it.  It is one thing to get a system to sound good. It is another issue to get it to image properly. You can get a fine two dimensional image out of a poor sounding system but you can not get a good three dimensional image out of a poor sounding system. You can get a wide sweet spot with a two dimensional system, but there is only one sweet spot for the third dimension and you can hear this by simply shifting your head side to side. Certain issues like a bad crossover design will permanently preclude  a system from getting that third dimension. Variances in frequency response between the two channels is another common factor that prevents a system from achieving that third dimension. This is why measuring a systems amplitude response is so important, but you also have to have the ability to alter amplitude response without adding distortion, DSP again. Group delay is  another issue. Then there is room acoustics. That third dimension is the most fragile of all audio characteristics. All this is a great argument for active loudspeakers and we have had the capability to make any loudspeaker "active" since around 1995 with the foundation of TacT Audio. TacT is now Lyngdorf and other companies have entered the market such as Trinnov, Anthem, Legacy and my personal favorite, DEQX.

@kota1 

I guess you are very much like me. We never sleep:-)

First of all we need better definitions. I am referring to 2 channel systems. I have a 2 channel system , but it is comprised of 6 individual loudspeakers forming a full bandwidth line array. 

When I refer to "good hearing" it is not just the measured performance of the ears themselves, but also the training and interpretive powers of the lump connected to them. Not a problem. Once exposed to such a system you will never forget it. I still have vivid recollections of the High school teacher's apartment and system. 

I must be a fool then. With your eyes closed playing a 24/192 version of a great live recording like Arctic Monkeys Royal Albert Hall or the perennial Waiting for Columbus, the only audio clues that you are not at the real performance is the crowd noise coming only from in front of you and an image that is much too good for a concert of this nature. Playing music this way is for demonstration purposes only. Running at such a volume on a continual basis is not good for your ears or your marriage. My house is an open design with very few doors. The media room essentially exits into a large cavity. There are enough late reflections to convince the brain that you are in a larger venue or not necessarily in a small one.   Playing classical music or acoustic jazz is probably a better, safer indicator and will produce the same results. 

Immersive sound? Do you sit in the center of a band or orchestra?  Immersive sound is for theater use. My system does double for theater use but I am not willing to compromise it's 2 channel performance 

You are wrong again... Sorry...

Immersiveness is an acoustic concept which is in the reach of two speakers system not only theater system and defined by the ratio between listener envelopment ASW/LV and the sound sources holographic volume ratio ...

Acoustic is key in audio not the gear....With the Dr. Choueri BACCH filter it could be very easy to attain complete immersiveness by the way with headphone or any stereo speakers...

My headphone are in their own specfically headphone way "immersive" as was my two speakers/room...( not my actual cheap speakers/basement corner , here i enjoy imaging but not immersiveness for sure, i could not tune resonators there to modify the pressure zone distribution this is why immersiveness is not possible in my basement only a good imaging )

This means that i as a listener i feel as if i was among the musicians on the musical scene with the musicians around me , it is recording dependent for sure... With organ Bach music and Marie Claire Alain recording for example i am as a listener in a church, no more in my room , and the headphone soundfield is "out of my head" ... In my acoustic room it was like that but not as much precise because of my speakers specs limitations which were less performative than my hybrid top headphone now...

By the way it was very hard to find a set of headphone able to do that and optimize it, it takes me 6 months... With the headphone it was necessary to use electronical equalization too by the way to go nearer the Harman curve , the mechanical equalization was done already internally by the designer with a grid of 5 Helmholtz resonators 😊 the AKG K340 is vastly misunderstood, their internal shell is a masterpiece of acoustic and their genius designer was a physicist founder of AKG ...

Immersive sound? Do you sit in the center of a band or orchestra? Immersive sound is for theater use. My system does double for theater use but I am not willing to compromise it’s 2 channel performance