From: bell@asdsun.larc.nasa.gov (John Bell)
Subject: Re: Sound reinforcement questions
Organization: NASA Langley Research Center, Hampton, VA  USA
Date: Fri, 4 Sep 1992 18:28:47 GMT

In article <1992Sep4.141808.20794@uc.msc.edu>, dpm@msc.edu (David P. Mottaz) writes:
|> What is the best mic placement for mic'ing up a guitar amp(a combo
|> with one 12" speaker).  I have a Shure SM-57 to handle the chore.
|> This is for live performances.  I have heard several opinions about
|> this and usually its backed up with "well I always heard...".  What
|> are the differences in sound from having the mic aimed at the middle
|> of the speaker about a foot away vs having the the mic close to the
|> edge of the cone vs laying the mic in the back cavity of the amp vs...

  I put the mic about midway between the edge of the speaker and the center.
I don't have any technical reasons for this, but over the last five years or
so of trying different configurations, it seems to work best. I find that
the best results are with the mic about 1-3" from the front of the cabinet.
THe proximity effect enhances bass response, which is helpful, because many guitarists adjust their amps for maximum treble respinse (sounds better and clearer on stage, but sucks through the mix). Close miking also provides
more headroom before you get feedback, enabling the guitar amp to be turned down, resulting in more sound from the stacks and less from the stage amps - 
this gives you a lot more control through the mix.
|> 
|> Another area of concern;  We have never been able to get a very good
|> sound from the kick drum.  It's a huge Tama.  It has a lot of initial
|> attack "thwap" but it lacks serious "boom".  This is acoustically(sp?)
|> and it(of course) doesn't get any better amplified.  He uses a felt
|> beater.  I don't know what else is needed to diagnose this one.  Any
|> ideas?  The drummer for some unknown reason is reluctant to analyze
|> this so I am fishing around for solutions.
|> 

   Huge kick drums usually, IMHO, sound crummy when miked. You didn't specify
how the drummer has the kick drum tuned, but improper tuning can make it
nearly impossible to mic a good sound. Is the kick drum a one- or two-headed
drum. If it has a front head, you may want to try cutting a small hole in the
front head so you can put a mic inside the drum. Experiment with different
locations for the mic, depending on how much of the pedal impact you want to
pick up vs. drum resonance. Different mic's sound very different in kick drums;
I've had good luck with SM57's (which are cheap and durable), as well as 
various more expensive mics.
   I'm not sure what "serious boom" means to you. Are you after a heavy metal
type of sound, or a tight-but-heavy dance mix kind of sound, or what? Most
kick drums don't actually produce extremely low frequencies, especially when
compared to the lower toms, so you may be trying to emphasize the wrong 
frequencies when you mix the sound. I have found that a ten-band or parametric equalizer can really help with kick drums, since the standard frequencies on
most 3 or 4 point equalizers found in mixers are not the frequencies you need
to bring out the kick drum.

   I hope all this helps, but if not, at least you can have fun experimenting!
Good luck.

-----
John Bell
NASA Langley Research Center
my opinions are not my employer's (obviously)
Internet: bell@haloe.larc.nasa.gov
804-864-7121
Xref: sparky rec.audio.pro:1612 rec.audio:11989