Handbook for Sound Engineers

Consoles 987

used to instruct the microphone’s processing. The
microphone’s sample rate may either free run, in which
case it is a master (but will probably need SRCing to
work in a system of any complexity), or it can be slaved
to the synchronizing word clock. The latter is favored, if
available.
Present digital microphones using AES-42 have a
choice of termination, depending on whether the system
into which it is plugged already speaks AES-42 in that
particular microphone’s dialect (and so control from
that system is implicit), or via an external interface box
which permits a computer running the appropriate and
proprietary control software to talk to the microphone
and audio data recognizable as AES-3 or S/Pdif stripped
off for use.
An interesting side note is that Neumann, a major
influence over the scheme and early adopter, make
claims that such an arrangement results in better overall
dynamic range than traditional microphone connections.
The premise is that conversion of the capsule audio
down to the common low-level microphone intercon-
nection standard of 150:/sent through a wire/low-
noise amplification/then conversion of that signal to an

A/D convertor within the console, is intrinsically noisier

than the more direct connection of the capsule with

optimum impedance transfer to the convertor within the

microphone itself, without intervening transformations

and stages. Their claims of convertor performance so

used are impressive.

25.25.2 Moving Audio—Multiple Paths

More than a stereo pair calls for more radical answers,

and as is typical with fast-moving development tended

to outstrip standards-making—never mind the commer-

cial impetus to try to capture users within a proprietary

format. Two formats, one from pro audio, the other

from semi pro, stand out from the earlier days of multi-

track recorder/console interconnection:

25.25.2.1 AES-10—MADI

This format is very common for the interconnection of

digital reel-to-reel recorders (whoever thought we’d be

weeping nostalgic for those?) and older large-format

Figure 25-153. AES-42.

Computer

Capsule bias

inverter

dc power

Sync

Data

DSP

HPF

Phase

Compressor

De-esser

Limiter

AES

O/P

Framing

A/D

Control

Gain

Power/controlrecovery

XLR

(M)

Attenuator

A. An example AES-42 digital microphone.

Power/

clocks

TCP/IP

or

USB

or

MIDI

AES

S/PdiF

Tx

B. Basic AES-42 host interface C. Option example.

XLR (F)

AES

Rx

+10 V

Sync clock

Control data

Status data

Audio data Console