Working with MS theory if you had a Single Point Source Pulse

[Tom McC]

Originally Posted by Yannick

On the contrary, it's even more precise than Blumlein, because actually that technique requires playback on speakers in a 90 degree setup, instead of 60 ...

Can you please cite a literature source supporting that '90- instead of 60 degree' assertion, Yannick? I was unable to locate any such explicit statement in any of Blumlein's patent applications. Or maybe you've drawn that conclusion from your own hands-on experience?. Thanks.

[Yannick]

Hmm, the moment I typed this, I knew I forgot something.
I'll have to think about where I read it. It must be 15 years ago.
Since then I did test this setup (you can do this easily), and it did sound much more convincing. It whiped any claims about AB being more spacious off the table. Precision was kept and it sounded even more realistic. I think I never bothered to look back, because nobody/nowhere has speakers setup in a 90° triangle (how do you call this thing in Englsh ?).

[boojum]

Originally Posted by Yannick

<snip>

I think I never bothered to look back, because nobody/nowhere has speakers setup in a 90° triangle (how do you call this thing in Englsh ?).

"Right angle triangle." A ninety degree angle is also called a "right angle" in English. Why I have no idea. Maybe , " . . . it just seemed like a good idea at the time." LOL

[Tom McC]

Originally Posted by Yannick

Hmm, the moment I typed this, I knew I forgot something.
I'll have to think about where I read it. It must be 15 years ago.....

I'm ahead of you there - often forget stuff before I type

My understanding of this angle business was:

a) Classic Blumlein (XY Fig-8's at +/- 45°) has a Stereophonic Recording Angle (SRA) of ca. +/- 38°.

b) This means that sound sources spread evenly throughout an arc of 76° (subtended to the mic stand) will when recorded get reproduced with an even spread between the two playback speakers, with full width utilization.

c) But if, say, an orchestra is actually disposed on the podium over a wider arc of 90°, then there is poorer lateral discrimination of the sound sources near the outer edges of the arc, and those outside edge sources get "more bunched up" near the speakers.

d) This bunching phenomenon - when the sound source arc exceeds the SRA - is independent of the arrangement of the playback speakers. Sure, everything will be proportionately wider if the speakers are arranged at +/- 45° instead of a perhaps more typical +/- 30°, but the issue of uneven distribution will in principle remain.

Note, I'm not talking about capture of very widely-spaced sound sources, with their attendant issues of significant pick-up from the Fig-8 antilobes, phasiness, imaging outside the speakers etc.

In any event, Blumlein remains the one mic technique that has made the hairs on the back of my neck stand on end