Microphone Installation; Half-Inch Preamplifier With Half-Inch Microphone; Half-Inch Preamplifier With One-Inch Microphone; One-Inch Preamplifier - BRUEL & KJAER 3923 Instructions Manual

Chapter 2 — Operation

Microphone Installation

7. Unlock the trunion and adjust the counterweight positions until the boom is
8. Lock the trunion.
2.3 Microphone Installation
The microphone assembly should first be attached to the Microphone Suspension
UA 0502. Both one-inch and half-inch microphone assemblies may be used. The
suspension does not accept the quarter-inch Microphone Preamplifier Type 2618.
The Suspension prevents unwanted vibration being transmitted through the boom
to the microphone. It consists of a support and two sets of preamplifier yokes, for
both one-inch and half-inch preamplifiers. Installation of the microphone assembly
depends upon the microphone size and preamplifier type.
2.3.1 Half-inch Preamplifier with Half-inch Microphone
When a half-inch preamplifier (e.g. B & K Type 2669C) is used with a half-inch
microphone (or smaller cartridge with corresponding adaptor), two half-inch Yokes
DS 0412 are used (see Fig.2.2). Fit the Yokes to the mounting support and slide the
preamplifier through the Yokes, starting from the support ring. Push the preampli-
fier as far as possible to keep the influence of reflections from the suspension to a
minimum. For the best vibration insulation, the Yokes should be adjusted to be
parallel.
2.3.2 Half-inch Preamplifier with One-inch Microphone
When using a one-inch microphone mounted on a half-inch preamplifier fitted with
Adaptor DB 0375, both a half-inch and a one-inch Yoke must be used (see Fig.2.2).
The half-inch Yoke is fitted close to the support ring. Slide the half-inch preamplifi-
er (without microphone and adaptor) through the Yoke and fit Adaptor DB 0375 to
the preamplifier. The one-inch Yoke is then slid over the Adaptor and fitted to the
support. Adjust the Yokes to be parallel and mount the microphone on the pream-
plifier.
2.3.3 One-inch Preamplifier
With a one-inch preamplifier two one-inch Yokes must be used. To allow mounting
the microphone as far away from the suspension as possible, the Adaptor Ring
DP 0217 should be fitted over the cable entry of the preamplifier (see Fig.2.2).
Again, the Yokes should be adjusted to be parallel when the preamplifier and the
Adaptor Ring have been fitted.
2− 4
balanced. Lock the counterweights. Note that the balance does not need fine
adjustment at this stage since the balance needs adjustment after microphone
installation.
Rotating Microphone Boom Type 3923
User Manual
Brüel & Kjær