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 9-Volt Phantom Power (switch is out) for this application.
Positioning the Crown GLM-200 Microphone
It's worth taking the time to experiment with mic placement. Here are some suggestions to help you
get started:
Internally mounted Microphone(flat top guitars)
Start with the Microphone centered in the soundhole, slightly below the top. Position the face of the
Microphone (marked "FRONT") toward the inside of the instrument. Tilting the Microphone as much
as 90° may help reduce boominess.
Externally mounted Microphone
(violin, bass, cello, 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° may help reduce boominess. Placing the Microphone directly over an
F- hole will produce 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 output.
A
DDRESSING
F
EEDBACK
Low Frequency Feedback
All stringed instruments' sound chambers are tuned to resonate at an optimum frequency, in the instrument's lowest octave. Placing a
Microphone directly over the opening of the instrument may result in feedback at this "cavity resonance".
Typical Resonant Frequencies:
Guitar; 95-105 Hz
Bass; 65-75 Hz
Violin; 275-300 Hz
Cello; 125-135 Hz
To Minimize Cavity Resonance Feedback:
1. Position the Microphone away from the opening on non-flattop instruments. This works well in low volume settings.
2. Turn down the bass control on the Microphone Channel.
3. Push in the bass cut switch on the Microphone Channel.
4. Invert the Phase switches on both Channels. (See Page 6 )
5. Insert an outboard equalizer after the Pocket Blender's output (i.e.):
a. Notch Filter: The Fishman Pro-EQ Platinum has a notch filter for eliminating low freq. feedback.
b. Parametric EQ: We suggest cutting 5 dB at the instrument's cavity resonance (see above) with a .5 octave bandwidth (Q).
c. Graphic EQ: Cut 5 dB at the instrument's cavity resonance (see above) with 1/3 octave cuts on either side of the center
frequency.
18
P o c k e t B l e n d e r
The Pocket Blender allows you to combine the benefits of both pickup and microphone signals to achieve results not
available by simply using one or the other. With this system, a microphone rounds out the dry, direct sound of a pickup
- while the "bite" of a pickup adds focus and definition to the microphone sound.
We recommend (and sell) the Crown GLM-200 mini-microphone for the Pocket Blender. Electret microphones made
by other manufacturer's can be modified for use with the Pocket Blender (contact the manufacturer for specific wiring).
2 - Stereo Instrument Cable
For convenience, we use a TRS
stereo instrument cable to get the
individual microphone and pickup
signals from the instrument into the
Pocket Blender. The Pocket Blender
supplies a 9-Volt bias voltage through
the ring connection that in turn
powers the mini-microphone.
3 - The Pocket Blender
Each channel of the Pocket Blender is set up for the particular signal conditioning requirements of microphone and
pickup. Once the pickup/microphone signals are blended, the composite signal can be routed to amplification,
recording gear or signal processing equipment via XLR and 1/4" outputs. An effects loop is also included for each
channel.
I
NSTALLING A
P
ICKUP
/ C
ROWN
GLM 200 M
ICROPHONE
C
OMBINATION
O
N
Y
OUR
I
NSTRUMENT
Before you begin using your Pocket Blender, have a repair professional install the appropriate pickup and
microphone combination for your instrument.
Note:
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).
Three Common Scenarios:
1 - W
IRING A
P
ASSIVE
P
ICKUP
& M
ICROPHONE
A passive pickup is any transducer (piezo or magnetic) that works without a battery.
Note:
To minimize crosstalk with a passive pickup, use a "2-pair" premium stereo cable (Fishman part # ACC-BLE-15C) with
separate shields for both the pickup and microphone signals.
1. Connect red microphone wire to ring terminal.
2. Connect white and shield microphone wires to sleeve.
3. Connect pickup signal wire to tip and pickup shield to sleeve.
4. Connect supplied zener diode in place between red wire (ring) and ground (sleeve).
Note that banded side of diode must be closest to red wire.
3
P o c k e t B l e n d e r
Shield to
Sleeve
Pickup Signal
to Tip
Microphone to Ring
Zener Diode
between Ring & Sleeve
Ring
Tip
Sleeve
Stereo Plug
Stereo Jack
MORE BASS
LESS BASS
