Presonus Audio electronic DigiMAX 96k User Manual

Product Reviews

Audio Media, June 2001
DigiMAX 96k

By Simon Tillbrook

To review a microphone pre-amplifier is an awkward prospect. These items in our
effects rack hold such importance to the overall sound, but their performance in this
respect is subjective.

So many variables are involved when judging them: Microphone choice, placement,
acoustic environment, and so on. On this occasion however the task was made so
much easier by a unit that was universally liked by all who came into contact with it.

The PreSonus DigiMAX is an eight-channel microphone pre-amplifier with dual
domain limiters and digital outputs. Now there's a mouthful. This unit comes in two
parts — a single rack space processor and a separate power supply. Four green LEDs
on the face of the power supply confirm the presence of each of the power rails.

The front of the very pretty rack unit (sculptured aluminum panel with blue anodized
knobs) is clearly split into eight numbered sections. Each channel consists of a dual
concentric rotary control, the inner part, the pre-amplifier gain control, utilizes Class
A discrete input buffer with a dual servo gain stage giving 60dB of gain (the
amplifier has inherent gain of 12dB, so a total gain of 72dB).

The outer part controls the dual domain limiter's threshold, from 0 to +24dB. All
channels have switchable phantom power, found rather annoyingly on the rear of the
unit, a pad switch reducing the incoming level by 20dB, and a unique feature called
EQ Enhance. When pushed this engages a signal cut of 3dB, centered at 1kHz, from
250Hz to 5KHz to give a smoothing effect on the mid-range.

In addition to these features, Channels 1 and 2 also have a phase reverse button and
an instrument input accessed by a standard jack socket.

PreSonus Audio Electronics | 7257 Florida Blvd, Baton Rouge, LA 70806

T 225.216.7887 F 225.926.8347 | www.presonus.com

Product Reviews

It is when you take a look at the rear of the unit that things get interesting. You are
confronted with a multitude of connect ability.

We have eight XLR microphone inputs, eight TRS quarter-inch jack analogue
outputs, 24-bit ADAT optical digital output, a chassis mounted nine-pin connector
that (with an optional cable) can provide either 24-bit four pair stereo SPDIF or
AES/EBU outputs and finally external clock sync input and master clock output
(sample rates 32K, 44.1K and 48K)... phew!! The best part about all this is the fact
that they all work simultaneously, giving us a great number of operational choices.

The principle behind Presonus's dual-domain limiter is to employ RMS as well as
peak-level detection. Most compressors use RMS detection, but are generally not
fast enough to catch some transient peaks. Limiters, albeit fast, can be too harsh in
their processing, so the combination of the two approaches makes for a more musical
limiter. The peak detection is only really used on the unit to stop the A/D from
clipping.

In Use

A pre-amplifier with a variety of direct digital outputs clearly lends itself as a front
end to a computer-based recording system, and the fact that all connections work
simultaneously allowed me to record a variety of signals to several different
recording systems at once... very handy.

I used the ADAT optical output to a 20-bit XT, SPDIF to Pro Tools via an
AudioMedia card and balanced analogue outputs to a Studer A800 MKIII. Not too
shabby an arrangement for such a test.

We began by recording drums (a standard five-piece kit) through the DigiMAX to all
systems, firstly without any limiters. Full beefy sound from bass drum, overheads and
high-hat sounded particularly crisp and detailed. There was no real noise from the
DigiMAX at all. Very quiet and smooth. The results to both the ADAT and Pro Tools
were particularly pleasing, but when you start to play with the limiters things really
do start to come to life and jump out at you — a really punchy dynamic sound. The
DigiMAX really began to impress me.

Directly inputting bass guitar through the front of the unit was equally impressive.
Once again, it was with the Pro Tools system in particular that you appreciated how
full and driving the lower frequencies sounded on the hard disk.

Recording acoustic six string in stereo through two AKG C451E/CK1's we had a
gloriously smooth sound. The detail in the high-frequency region was nice and bright
without being too hard. The DigiMAX coped with all the variations thrown at it with

PreSonus Audio Electronics | 7257 Florida Blvd, Baton Rouge, LA 70806

T 225.216.7887 F 225.926.8347 | www.presonus.com