2
MODEL BG5.1
UNIDIRECTIONAL CONDENSER MICROPHONE
The BG5.1 microphone utilizes an advanced condenser
transducer design for use in professional vocal sound rein-
forcement and project studio recording. Its electret cartridge
has a wide frequency response optimized for vocals, and its
high sensitivity and low noise make it an ideal choice for pro-
ducing quality demo tapes. The BG5.1 maintains a cardioid po-
lar pattern throughout its frequency range, ensuring high gain-
before-feedback, maximum isolation from undesired sound
sources, and minimum off-axis sound coloration. Operating
voltage is supplied by phantom power from a mixer, or an inter-
nal AA battery for 10,000 hours of continuous use. Typical ap-
plications for the BG5.1 include studio vocal tracks, lead vocal
sound reinforcement, and high-profile public address.
GENERAL RULES FOR MICROPHONE USE
1. For optimal signal-to-noise ratio, place the microphone as
close as possible to the desired sound source.
2. For the best gain-before-feedback and isolation from unde-
sired background noise, aim the microphone toward the
sound source and away from undesired sound sources
(Figure 1). The BG5.1 features a cardioid polar pattern
which is most sensitive to sound directly in front of the mi-
crophone, and least sensitive to sound directly at 180
.
3. For the purest reproduction of sound, use only one micro-
phone per sound source and use the fewest number of mi-
crophones necessary for the application.
4. For maximum isolation, keep the distance between micro-
phones at least three times the distance from each source
to its microphone.
5. Placing the sound source close to the microphone improves
bass response (Figure 2). This phenomenon is known as
proximity effect and can be used to achieve a fuller sound,
especially for vocals during soft passages where extra em-
phasis is needed. For instruments, proximity effect can be
used to change bass output without using tone controls.
6. Placing the microphone too close to acoustically reflective
(smooth, hard) surfaces will result in a poor frequency re-
sponse and will increase the chances for feedback. To mini-
mize this effect, place microphones as far as possible from
acoustically reflective surfaces.
7. Add an external windscreen when using the microphone
outdoors to reduce wind noise.
8. Do not cover any part of the grille with your hand (Figure 3).
Covering the grille distorts the polar pattern, increasing the
chances for feedback.
9. It is important to keep foreign particles out of the grille and
windscreen because they may alter the frequency re-
sponse of the microphone. The grille may be periodically
cleaned using warm, soapy water. Rinse with plain water
and let it dry before replacing. Also, avoid exposing con-
denser microphones to heat and high humidity.
SPECIFICATIONS
Type
Condenser (electret bias)
Frequency Response
70 to 16,000 Hz (Figure 2)
Polar Pattern
Cardioid (directional), symmetrical about axis (Figure 4)
Output Impedance
600
Ω
Recommended Load Impedance
800
Ω
minimum
Sensitivity (at 1,000 Hz)
Open Circuit Voltage
–49.0 dBV/Pa (3.5 mV)
. . . . . . . . .
1 Pa=94 dB SPL
