Recording - August 2014 - 56

B Y PA U L V N U K J R .

Harrison 832c Filter Unit
Nashville-based Harrison is best known
for recording consoles, starting with the
Series 32 debuting in 1975. Later consoles
such as the Series 10, Series 12, and Trion,
would find homes in both film and recording
studios worldwide and be used by such
groups as AC/DC, ABBA and Led Zeppelin,
but it is the Series 32c which continues to
garner the most appreciation, due in no
small part to it being used by Bruce Swedien
to record Michael Jackson's Thriller. Of
course, finding (much less affording) a vintage 32c desk for your studio is not exactly
easy. Luckily, Harrison offers other options to
get the Series 32c sound into your room!
There is Harrison's collaboration with
Great River Electronics, the 32EQ 500 Series
module that we reviewed in our October
2011 issue. Next, there is the Harrison
Lineage 8-Channel microphone preamp,
which was reviewed in our February 2012
issue; it puts one pair each of preamps from
the Series 32c, 10, 12, and Trion into a 19"
single space device. Later this year, Harrison
will release a rackmount 32cs channel strip
with preamps, filters, and EQ from the 32c
console. For plug-in fans, there is also a
Harrison-approved 32c plug-in for the
Universal Audio UAD-2 and Apollo systems.
This month we bring you the newest
option, the Harrison 832c Filter Unit. It's a collection of eight individual 32 Series high- and
lowpass filters in a single rack space unit.
Classic looks, build and controls
The 832c is built like a tank. It's robust and
heavy with great-feeling knobs and switches.
Visually the 832c is akin to the Lineage. It
features similarly styled knobs, LEDs and buttons, along with a matching brownish-black
rough coat finish with white silkscreened lettering that gives it a late-'70s visual vibe. This
nods back to a time when gear was built to
be functional rather than blingy.
The front panel sports eight identical filter sections, each with a red highpass
knob, a white lowpass knob, a trio of
grey toggle buttons for engaging the
high- and lowpass filters as well as a high
pass filter bump, and a 7-stage LED
meter. Around the back the 832c offers a
bit of a surprise; rather than cramming
the real estate full of sixteen balanced
1
/4" TRS or XLR jacks, the designers at
56

RECORDING August 2014

8-track tone-shaping goodness in rackmount format

Harrison chose to use two TASCAM spec
DB-25 (D-Sub) connectors.
The tech side
The highpass control filters out low frequencies from 25 Hz to 3.15 kHz at 12 dB
per octave, while the bump control engages
a gentle resonant peak of about 5 dB at the
cut frequency. In use this adds a bit of lowend heft and presence to the signal, while
simultaneously filtering out the frequencies
below it, for a punchy clean sound devoid
of mud and rumble. The lowpass control filters out frequencies of 180 Hz to 20 kHz,
also at 12 dB per octave.
Additional specs of the 832c include a
10 kilohm input impedance, less than 50
ohms output impedance, and maximum
input and output levels of +24 dBu. It has
less than 0.01% of THD (1kHz @ +24 dBu),
a ±0.25 dB frequency response of 20
Hz-20 kHz with the filters out, and a +0, -3
dB frequency response of 20 Hz-20 kHz
with the filters in.
The Harrison 832c is quite straightforward
to hook up and use. My studio is equipped
with an Audiolot Mixbay, a 192-point patch
bay that also uses DB-25 D-Sub connectors,
so hooking up the 832c only required a pair
of D-Sub cables. If your studio is not D-Sub
equipped, you'll need to budget for two DSub breakout snakes that terminate in the connectors that your system uses.
The why?
It's easy to look at this piece and think,
"Eight sets of simple filters... why would I
need that?"

On one hand, there are many more exciting and alluring pieces of audio gear on the
market, from compressors to EQs and
effects, but there is a reason that high- and
lowpass filters are present on almost every
full-scale professional mixing console,
whether analog or digital. They are typically the first component in the mix chain and
are at the foundation of any good mix.
While I don't use a full-blown console
in my studio any more, in my job as a live
sound engineer I can't think of any channel in a mix where I don't have highpass
filtering engaged at some level to clean
out the clutter and rumble of my live
mixes. I admit I use lowpass filters more
sparingly, and not on every channel, but
there is always some source in a mix that
needs its piercing harshness tamed.
In use
Historically, the high- and lowpass filters
found on the original Harrison 32c are some
of the most respected filters on the planet. If
you read about the Harrison/Great River
32EQ online, you will find the high- and lowpass filters are among its most favored features as well. In other words, these filters are
the real deal, and people are happy to have
them back!
Functionally, unlike the filters found on
many mic preamps and even many classic
channel strips (which are either stepped or
even fixed at a single frequency), these are
fully variable and very powerful-with the
right settings, between them the two filters
can virtually eradicate a signal. Using them
is simple and intuitive-just turn the knob

Recording - August 2014

Table of Contents for the Digital Edition of Recording - August 2014