Loudspeakers and room as a system

[cbdb]

and saw that virtually all expensive stereo microphones are dipole microphones (Blumlein pair, the most expensive are ribbons).

Most have adjustable patterns,that go from omni to card to bi-polar(figure 8). (arent the expensive ones mostly large diaphram condensers?) But people still use pairs of mono mics for stereo so they can seperate them. The most popular stereo mic configuration is the X/Y pair, it picks up the least amount of room (and other instruments) (the Blumlien records all the room reflections in 360 degrees and then stuffs them into 60 degrees for playback, exagerating the amount of room in the recording) and with X/Y the stereo width can be adjusted by changing the angle. Stereo is an illusion (especiallyplayed over 2 speakers), there is no "right" or "natural" mic configuration (including Blumelien) they all create approximations of reality (you will never hear the reflection off the back wall of the recording space come from behind you on playback). The recording engineer knows this and the mics become a tool to shape the sound, not capture an exact replica (which is impossible). As soon as your sound goes thru a mic your producing it (and changing it, very few "great" mics are flat or have even polar responses), and trying to make it sound as good as possible. But this means different things to different people and always will.

[graaf]

Originally Posted by el`Ol

The prototypes had an excellent imaging when fed with real-acoustic recordings and some problems with synthetic acoustic: The instruments were either fixed to the speakers or formed a clump of mud between them. Now the real acoustic recordings are diffuse and without depth, whereas the synth acoustic recordings are much better now and in fact the field where the speakers perform best"

so the CFS still wins as a stereo "allrounder"

BTW I have to say that after many experiments I grew tired of any kind of stereo and I am finally fed up with all those pseudo-real effects

I still have two spekaers suitable for CFS but I use only one

It all started by accident (when a kitten destroyed one of the speakers) but when after a while and fixing the problem I was able to go back to stereo I have discovered to my own suprise that I am unhappy with it, that I had enjoyed the music better earlier in mono (in the CFS configuration of course)

so I am definitely into mono now and I have to say that I am really happy listening exclusively to the MUSIC itself again

I know and in fact I experience that not every stereo recording sums into mono well but it bothers me less then distracting stereo pseudo-realistic effects

Originally Posted by el`Ol

What about real wool felt?

should be the best
felt is very effective and very linear AFAIK, I haven't got the numbers before my eyes but IIRC 5<10 cm of felt gives 90% reduction of reflected energy in broad spectrum 500 Hz<

[el`Ol]

Originally Posted by markus76

I suspect the room's reflection pattern is to "blame"

In fact I did not mark the positions of the speakers, but placed them more or less at the same places from my memory. Now I did the positioning with measurement and found the imaging is dependent on

1) single peak reflection
2) same reflection pattern on both channels

So I was able to get almost the original behaviour again.
"Almost" because I couldn't get rid of the two-peakiness completely and this could be due to the foam. I don't know yet whether I will be fanatic enough to replace the Basotect by wool felt, the result is good enough now.

What I find weird is that the reverb algorithms work much better in an asymmetric environment.

[el`Ol]

Originally Posted by graaf

I know and in fact I experience that not every stereo recording sums into mono well but it bothers me less then distracting stereo pseudo-realistic effects

The ceiling firing Ciare HX160 is an excellent mono driver. Originally I planned to use it as CFS in hm's Lure backloaded horn (simulates well). The problem was that two of them still played mono, so I discarded this idea.

[markus76]

Originally Posted by el`Ol

So I was able to get almost the original behaviour again.
"Almost" because I couldn't get rid of the two-peakiness completely and this could be due to the foam. I don't know yet whether I will be fanatic enough to replace the Basotect by wool felt, the result is good enough now.

There's probably a difference in the flow resistivity of foam vs. felt. Which one did work better? I guess the absorptive properties of felt vary greatly. With foam you should get more predictable results.

Originally Posted by el`Ol

What I find weird is that the reverb algorithms work much better in an asymmetric environment.

What is your subjective sensation? "They (sounds) are here" or "you are there"?

[el`Ol]

With the felt the reflection was shorter and had no repetition. With careful placement now one can't really see two peaks but on can see the reflection consists of two (united) parts that look very similar. To reliably say whether there is an audible difference one would have to do A-B comparison, maybe I believe to hear a difference because the measurement is different. I think there was better focus before.

With synth acoustic I neither have the feeling of being there nor of they are here because it differs much from the natural impression. Just some kind of "envelopment", audible stereo panorama and inaudible speaker positions.

[adason]

"so I am definitely into mono now and I have to say that I am really happy listening exclusively to the MUSIC itself again"

that would not work for me, I tried many times, every time I get great speaker, but only one, for instance big old Altec coaxial, or Trusonic coaxial ... each time I try listening in mono, everytime there is something missing, its like looking at the world with one eye only, suddenly whole space perception is gone, the same with mono, putting left anf right signal together just eliminates many fine nuances of music, plus in stereo its much easier to recognize and follow each instrument separately, especially in good live two mic recordings

mono? no thanks, its a step back
ed

[graaf]

Originally Posted by el`Ol

Just some kind of "envelopment", audible stereo panorama and inaudible speaker positions.

I think it's as good as it gets

[graaf]

Originally Posted by adason

"so I am definitely into mono now and I have to say that I am really happy listening exclusively to the MUSIC itself again"

that would not work for me, I tried many times, every time I get great speaker, but only one, for instance big old Altec coaxial, or Trusonic coaxial ... each time I try listening in mono, everytime there is something missing, its like looking at the world with one eye only, suddenly whole space perception is gone, the same with mono, putting left anf right signal together just eliminates many fine nuances of music, plus in stereo its much easier to recognize and follow each instrument separately, especially in good live two mic recordings

mono with CFS (which is a kind of Carlsson omnidirectional mono) in a relatively live room (typical living room without anty audiophile acoustical treatments) is VERY DIFFERENT
it is not at all like conventional mono ie. with two speakers or with one speaker pointing directly at the listener

"space perception gone", "elimination of fine nuances", more difficult "to recognize and follow each instrument" - it is all true with regard to conventional mono

but it is not at all true with regard to CFS mono

the only thing missing is left-right extension of the auditory event

in fact I find it easier to recognize and follow each instrument and to follow fine nuances in CFS mono than in stereo
and I think that it can be explained by the lack of distracting pseudo-real stereo spatial cues which confuse brain

[markus76]

Originally Posted by adason

each time I try listening in mono, everytime there is something missing, its like looking at the world with one eye only

That's exactly what happens. Another drawback is the wrong timbre of instruments mixed to the center because they are EQed for compatibility with stereo playback.

If you want real envelopment - and not only an unforeseeable spaciousness effect from strong room reflections - mono plus 2 surround channels at 90° would be more capable of delivering a realistic spatial sensation. But again, you'd need special recordings which are not available although 5.1 or 7.1 surround recordings would be suitable (because of the un-EQed center channel). But then, why omit the spatial information stored in the L and R channels?

Best, Markus