As an aside, on "accidental stereo…" Mark Obert-Thorn has recently produced a disc which makes use of the backup discs believed to be recorded with a different mic. With the use of the Capstan software, it was possible to sync the two discs well enough that it sounds very convincing to me. Lani Spahr is working on some of the Elgar.
You can hear a sample of Mark's work at the Pristine site.
On Saturday, August 30, 2014 8:09 PM, Tom Fine <[log in to unmask]> wrote:
I meant to say that two spaced omni's won't sum to mono very well. There is a distance where you can
successfully record something like a small jazz ensemble or a chamber classical ensemble without a
hole in the middle but have two much combing to successfully combine to mono. I think what you are
describing is ORTF-like 2-mic technique, which does sum to mono because the wavefronts hit both mics
close enough in timing to cause minimal cancellations when summed.
Can anyone point to a single M-S recording of a full orchestra? I'd think you'd not be able to have
a strong center AND wide/deep/high stereophony, it would be one or the other depending on how you
mixed it. I've heard of many engineers using one of the various crossed-matrix setups for a center
array and then using other mics on the sides and sometimes also filler mics. I suppose that would
work but what if, for instance, you have a solo cellist up front and slightly right or left of
center who is very "active"? I would think you'd have image-instability issues, perhaps because the
crossed-matrix array is accurately recording the bobbing and weaving of the "active" soloist.
Accurate it may be, but it's probably somewhat annoying on playback in the home. I think a single
omni in the middle eliminates this problem unless the "activity" is so extreme as to self-comb the
-- Tom Fine
----- Original Message -----
From: "[log in to unmask]" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, August 30, 2014 6:55 PM
Subject: [ARSCLIST] Accidental stereo (again)
> Tom Fine:
>>You definitely can't successfully sum 2-omni stereo to mono.
> I do not agree with the above, Tom.
> You only get comb filtering artifacts
> if the mics are fairly close together.
> If I use just two omni mics I use a
> spacing of around 60 cm for a nice
> stereo spread with no apparent
> hole in the middle.
> Each mic will get sufficiently different
> amplitude and time differences so when
> you mono them no comb filtering can be heard.
> Goes for the 3 mic omni one, M3, Mercury
> style mic set up too.
> Also the Decca tree, M5, with outriggers are free
> of audible comb filtering too.
> Comb filtering can only be heard IF there is
> enough correlation with a time delay between
> mics and that is not true of spaced mic techniques.
> Here the correlation between the mics are
> low so the sum together in mono fairly well
> in practice.
>> I think the Europeans who used MS or other crossed-matrix
>> methods were able to use one channel for mono (although
>> there were crosstalk phase-cancellation issues with that method).
> Not so.
> In M/S we have M-S = L and M+S = R when
> you matrix M and S to get stereo or L & R.
> When you have stereo or L & R when you mono L + R
> you get (M-S) + (M+S) = 2M.
> So the difference signal (-S) + (+S) cancels completely
> 100 percent and we are back to the original M signal
> only for 100 percent mono compatibility.
> One never ever use only L or R only just mono, L+R,
> the thing and we are back to the original M mic.
> Very simple in fact.
> No wonder that M/S is so popular in some quarters.
> Best regards,
> Goran Finnberg
> The Mastering Room AB
> E-mail: [log in to unmask]
> Learn from the mistakes of others, you can never live long enough to
> make them all yourself. - John Luther
> (")_(") Smurfen:RIP