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Re: Recording Quad

Subject: Re: Recording Quad
From: "Rob Danielson" danielson_rob
Date: Sun Feb 11, 2007 6:56 pm ((PST))
>Hello!
>
>I've been experimenting with recording in quad.  I've been using a 
>744 with an external pre
>for channels 3 and 4.  My dilemma with my current set up is: It is 
>impossible to make sure
>that all four channels are at the EXACT same level.  (On the 744 
>only channels 1 and 2 are
>linkable and have phantom power).  Any ideas?...  (Including buying 
>different gear).  I
>apologize if this has been brought up before (I'm new here).  And, 
>in advance, thank you for
>your time and knowledge.
>
>All the best!
>Jeremy

Hi Jeremy,

Welcome to the list. Yes, we have discussed this before, like
http://bioacoustics.cse.unsw.edu.au/archives/html/naturerecordists/2004-06/msg00206.html
It takes a while to figure out which unique terms to plug in, but 
list the archive is good.

Even if all four channels of a recorder were gained together, I 
suspect you'd encounter gain differences between mid and top scale. 
The best practical demonstration I can think of is to bundle all four 
mics together, point them at a soft 400Hz sine tone coming from a 
speaker about  2-4 feet away and make a few sets of "marks at 2 or 3 
ambient levels.  This will give you a good idea of how well matched 
your mics and pres are. You might be able to use the programmable 
gain input trim settings in the 744 menu to try to match a few of the 
more obvious knob settings, but chances are you'll decide your ears 
are the better judge.

In a natural setting, if your headphones are matched, you should be 
able to listen to the rumble on the horizon and match that level 
between two mics at a time within .5 dB.  If there's a louder, 
distant sound in one direction, rotate your surround rig so that its 
in between two pair and keep rotating the rig until they're all level 
"matched."

I use my musician friend's expensive SPL meter and spend an hour or 
more calibrating my 6 speakers. Then I sit down and work on them for 
a few hours and tweak the volume a bit by ear until they sound more 
"matched." The speakers have little quirks, my rooms has many quirks 
and my ears are not exactly the same. There's always some 
subjectivity and, thus, the need for science-- but both are usually 
involved and required. Rob D.







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