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Mic Memo      

 

 

Here's an unusal miking applica-
tion for sound reinforcement. 
How do you mike a folk harp? It 
is a small instrument about 4 
feet tall.

Try a Crown GLM-200, a mini 
mic with a hypercardioid polar 
pattern. 

Mount the mic inside the harp 
near one of the sound holes. 
You can attach the mic by taping 
its cable to the harp, or by using 
the supplied GLM-UM Universal 
Mount.

Ask the harpist to play as you 
monitor the sound. Adjust the 
angle and position of the GLM-
200 until you hear a tonal bal-
ance you like.

Many theater sound systems 
employ handheld mics for sing-
ers and lavalier (clip-on) mics for 
actors. Sometimes the sound 
operator is asked to make the 
lavalier mics sound the same as 

the handheld mics. What sort of 
equalization is needed to do 
this?

First, note that nearly all hand-
held vocal mics are directional, 
so they have proximity effect 
(bass boost when used close to 
the mouth). Omnidirectional 
lavalier mics have no proximity 
effect. To simulate that, you 
might boost 4 to 6 dB around 
100 Hz. (Be careful with feed-
back whenever you apply an EQ 
boost.)

Lavalier mics have a built-in 
high end rise to compensate for 
being off axis to the mouth. You 
might need to do more high-fre-
quency tweaking by ear. Also, 
most lavs exhibit a peak around 
630 Hz (about 3 or 4 dB, less 
than 1 octave wide) due to body 
diffraction and chest reso-
nance.  Cutting that frequency 
by the same amount can 
remove the "puffy" sounding 
midrange peak, making the lav 
sound more like the handheld 
mic.

Some houses of worship feature 
an electronic organ. Often it's 
necessary to feed the sound of 
this organ into the sound sys-
tem. It seems reasonable to find 
a line-level signal within the 
electronics and connect to it, or 
connect to the organ’s speaker 
terminals.  Unfortunately, these 
connections can cause several 
problems:

• Ground loops can create hum.
• You might be held liable for 
messing with the organ electron-
ics. 
• The organ technician might 
remove the connection.
• Many organs don't have a 
composite or full-range feed, 
meaning that the electrical sig-
nals to the various loudspeaker 
drivers are bandpassed. If you 
tap off a loudspeaker you may 
not get the full spectrum of the 
organ. If you combine the band-
passed outputs to get a full-
range feed, you might be held 
liable for tampering.
• A lightning strike that gets into 
the organ electronics might get 
into the audio system, or vice-
versa.

Using a mic instead of a direct 
connection avoids all the prob-
lems mentioned above. A close-
up omni mic, strategically 
placed, will pick up very little of 
the room and other sounds. We 
suggest the Crown GLM-100 
mini omni mic. It's very small 
and picks up down to 20 Hz. 

Note: This close mic placement 
is for sound reinforcement, not 
recording. If you want to record 
the electronic organ, place a pair 
of mics several feet away (about 
12 to 20 feet) to pick up the 
room reverb as well as the 
sound of the organ.

The GLM-100 looks the same 
as the GLM-200 pictured on this 
page.

Thanks to Pat Brown of Syn Aud 
Con for this idea.