Crown GLM-200 Specifications download pdf (Page 20)

USING OTHER MICROPHONES

The POCKET BLENDER is also compatible with other manufacturers' mini-

electret microphones. Consult the manufacturer for specific minimum power

requirements, wiring configuration and instrument mounting systems

(the Fishman microphone mounts are dedicated to the Crown GLM series).

Dynamic microphones (such as the SM 58) may be used with the POCKET

BLENDER. You'll need a low to high impedance adapter plugged into the

Ring jack of a stereo "Y" cable. Turn off the Phantom Power (switch is out) for

this application.

POSITIONING THE MICROPHONE

It's worth taking the time to experiment

with the placement of the Crown GLM-200.

Here are some suggestions to help

you get started:

INTERNALLY MOUNTED MICROPHONE

(flat top guitars) Start with the micro-

phone centered in the soundhole, slightly

below the top. Position the face of the

microphone (marked "FRONT") toward the

sound chamber of the instrument. Tilting

the microphone as much as 90 degrees

may help reduce boominess.

EXTERNALLY MOUNTED MICROPHONE (violin, bass, cello, f-hole mandolin,

arch-top guitar). Start with the microphone centered halfway between a bridge

foot and F-hole. Position the face of the microphone (marked front) towards

the instrument. Tilting the microphone as much as 90 degrees may help

reduce boominess. Placing the microphone directly over an F-hole will pro-

duce a deep, woody tone. However, the microphone will feedback at the

instrument's cavity resonance. This can be easily remedied by notching out

the feedback with an external equalizer (see below). Placing the microphone

over the soundboard will produce a tight, focused tone with more midrange

emphasis but less overall volume.

ADDRESSING FEEDBACK

LOW FREQUENCY CAVITY RESONANCE

All stringed instruments' sound chambers are tuned to resonate at an opti-

mum frequency, in the instrument's lowest octave. Placing a microphone

directly over the opening of the instrument may result in feedback at this "cav-

ity resonance".

Typical resonances are:

Guitar; 95-105 Hz Bass; 65-75 Hz

Violin; 275-300 Hz Cello; 125-135 Hz

To address Cavity Resonance Feedback:

1) POSITION THE MICROPHONE away from the opening on non-flat-top

instruments. This works well in low volume settings.

2) TURN DOWN BASS CONTROL on MICROPHONE channel.

3) PUSH IN BASS CUT SWITCH on MICROPHONE channel.

4) INVERT PHASE SWITCHES on both channels. See Pages 8 & 21

5) OUTBOARD EQUALIZATION: This works well in higher volume settings.

An external equalizer (such as the FISHMAN Dual Parametric D.I.) may be

used through the BLENDER's MICROPHONE channel EFFECTS LOOP.

See FIG. 1 See Page 16

a. PARAMETRIC EQ: We suggest cutting 5 dB at the instrument's cavity

resonance with a .5 octave bandwidth (Q).

b. GRAPHIC EQ (although less precise and much noisier) may also be

used. Cut 5 dB at the instrument's cavity resonance with 1/3 octave cuts

on either side of the center frequency.

HIGH FREQUENCY FEEDBACK

Occurs when the microphone's rising response creates a feedback loop with a

high frequency driver in your speaker system. This feedback usually starts

above 1.5 kHz, peaks at 4 kHz and subsides at 9 kHz. There are several

approaches to minimizing HIGH FREQUENCY FEEDBACK:

1) STRATEGIC POSITIONING: This works best in low to medium volume set-

tings. The simplest solution for this type of feedback is to keep the micro-

phone out of the path of the loudspeaker.

You can do this by:

a. Avoid standing directly in front of your amp.

b. Send separate MIX and TRANSDUCER signals to your soundman and

have only the TRANSDUCER signal sent to your stage monitor.

2) TURN DOWN TREBLE CONTROL on MICROPHONE channel.

3) REVERSE PHASE SWITCHES on both channels.

4) OUTBOARD EQUALIZATION: This works well in higher volume settings.

An external equalizer (such as the FISHMAN Dual Parametric D.I.) may be

used through the POCKET BLENDER's MICROPHONE channel EFFECTS

LOOP. See FIG. 2

a. Parametric EQ: We suggest cutting 5 dB at 4 kHz, with a 1.5 octave

bandwidth (Q).

b. GRAPHIC EQ (although less precise and much noisier) may also be used.

Cut 3 dB at 1.2 kHz. Gradually increase the amount of cut to -9 dB at 4-5

kHz. Above 5 kHz, gradually decrease the amount of cut to -3 dB at 10 kHz.

FISHMAN POCKET BLENDER

APPENDIX I: MICROPHONE Continued

1 2 ... 15 16 17 18 19 20 21 22 23 24

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Crown GLM-200 Specifications Page 20

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