From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Newsgroups: rec.audio.pro
Subject: Re: Bodhran (and other) spot mics
Date: 31 Dec 1992 13:58:58 GMT
Organization: NASA Langley Research Center and Reptile Farm
NNTP-Posting-Host: grissom.larc.nasa.gov

In article <725764795.5890707@AppleLink.Apple.COM> JOSEPHSON@AppleLink.Apple.COM (Josephson Engineering,VCA) writes:
> 
>This is as good as time as any to start a religious war on this newsgroup, and
>maybe we can all learn a little from it. 

Start a religous war?  This is a war that has been going on continuously since
the newsgroup started.  We're just throwing a few more bullets into the fray.

>First, some theory that seems always to be lost in this kind of discussion.
>Sound is a fiction. Mics don't pick up sound, they pick up changes in pressure
>and/or pressure gradient. Omni mics (Scott's B&K's, for instance) and cardioid
>mics (Mur's 57) work essentially differently. The omni mic reacts to audio-rate
>fluctuations in pressure, much as _one ear_ does. Think that's not significant?

Absolutely true.  But the microphone to pick is a factor of the recording
technique you use.  He was recommending using an SM57 very closely.  I was
recommending using an omni mike pulled very far back so as to get the
reflections from the room,
 
>Now some of my own prejudices. Leave the reverb out. For acoustic music that
>sounds good in its real space, it's a sure sign of an unsure balance engineer
>if reverb is needed _at all_, much less "...apply a lot of reverb..." or even
>"...add some rack/floor tom rock reverb to taste..." I'm assuming one thing
>here, that the recording venue sounds good live. 

Well, if you close mike an instrument like that, you will have to add some
reverb to prevent it from sounding extremely dry.  A much better solution
is to pull the microphone back into the far field and let the acoustics of 
the room introduce some real reverberation.

If that's not the case, go
>have a beer and look for a better hall. No amount of reverb will fix a bad
>natural acoustic unless you close mic things so severely that all the tracks
>are essentially anechoic. Likewise, if you can't get the balance of near and
>far field sound and natural reverb on tape to sound as good as it sounded in
>the hall, reverb won't fix that either. 

Unfortunately, a lot of studios (and, from the sound of it, the one used
by the original poster) are very heavily deadened.  This might be a good
thing for close-miked rock recording, but it's a major problem for doing
any real acoustic work.  Since so much of the recording these days is 
billionmiked rock stuff, finding decent places is fairly difficult.

Prejudice 2, mic it in stereo. Simply
>panning one mic into _amplitude_ position in a stereo mix ignores the phase and
>frequency response cues present in the real acoustic. You could elaborately
>fake it by applying delay and EQ to "correctly" position the mic in the sound
>field, but again the pickup would then need to be almost anechoic for this to
>work correctly. Admittedly, the imaging becomes a little more confused if you
>pan a stereo pair into the overall stereo mix, but the result is often more
>aesthetically convincing without having to add effects.

This is an excellent idea.  The problem is that if you close-mike the
instrument, you aren't going to get much in the way of good stereo effects.
Another problem is that when this stuff gets mixed down there is a strange
urge on the part of many technicians to spread the things wide across
the soundstage.  This results in fifty-mile long pianos wrapped around
orchestras and the like, and drives me up the wall.  So, if you do mike
in stereo, make sure the guy doing the mix has some clue about him.
 
>My choice (and this would apply to most spot mic situations where an overall
>stereo pickup just sounded thin in places) would be a semi-coincident stereo
>pair of condenser cardioids or figure-eight mics (four to ten inches and 60 to
>120 degrees apart), about four feet out (not necessarily straight out, see
>below) from the bodhran head. Again this is assuming that your main stereo
>pickup is all there, but just thin in spots. Try to get it right in your live
>2-track mix, but you might want to use more or less of the fill pair when you
>listen to the multitrack. 

Whenever I have done this in the past, I have found that the fill pair
alone often sounds better than anything else.  If God intended you to
cut it multitrack, He would have given you forty-eight ears.

>Few acoustic groups function well doing overdubs; the
>audible and extra-sensory interaction that happens live just doesn't get
>reconstructed in the overdub session unless _all_ of the players are accustomed
>to it. 

This is true... this is why I was suggesting only trying to overdub one
instrument.  I regard overdubs as a cheesy way of getting around bad acoustics,
but they are sometimes needed.

>Bottom line is, invest some time in experiment before you're ready to roll
>multitrack. Understand where in the sphere surrounding the instrument the
>different sounds are. All you really need is one mic amplified and fed to
>headphones that you wear while walking around. Analyse _with your ears_ what
>the differences are. Figure out the cause of each difference you hear. Figure
>out where in the frequency range the instrument-floor-mic and
>instrument-ceiling-mic bounce nulls are, and how this effects the overall
>transfer function of instrument to tape. Don't put the mic the same distance
>from the floor as it is from the ceiling (or walls, or boxes, etc.) And bottom
>bottom line is, don't look for a magic bullet. I've never found any hard and
>fast rules that work for every recording. I've seen famed English minimalist
>recording engineer Tony Faulkner in a session with 20 mics up, and multimondo
>DGG has made records where all they used was an ORTF pair.

I'll second that.
 
>Small commercial plug, my company makes good condenser mics of all the general
>types mentioned above (except the 57!) and I'd be happy to send a catalog to
>anyone who wants one, e-mail your s-mail address. I also make custom mics for
>special applications, and nearly all are entirely made in my shop (large and
>small diaphragm DC-air condenser types, not reworked electrets).

I'll second that too.  (David, do you guys make any decent 200V condenser
mikes with a cardioid or hypercardioid pattern?)
--scott