Recording - September 2016 - 62

equivalent of a loudspeaker without a cone, to start the vibrations spreading through the plate; the other was a contact
microphone to pick up the vibrations and turn them into electrical signals. There was a power amplifier (originally built using
vacuum tubes) to power the driver transducer, and a preamplifier to boost the output of the contact microphone to line level.
(Later models used solid-state amplifiers, and added a second
contact microphone to provide a stereo reverb output.) A sheet
of acoustically absorptive material could be moved closer to or
farther from the plate, to provide a variable degree of damping. (Moving the absorber closer made the reverb time shorter.)
I've seen many descriptions of the sounds of plate reverbs
using the word "pillowy". I'm not sure quite what that means
(after all, pillows don't reverberate), but it may refer to the
plate's general softening of the sound's transients. Plate reverb
has a sound that tends to be all-encompassing, particularly the
models with stereo outputs.
The original EMT plate reverb, the EMT 140, was about the
size of a queen mattress turned on its side, and it weighed a
few hundred pounds. That's what's usually being modeled when
manufacturers include a "plate" preset in digital reverb emulations. In the 1970s, EMT created a similar device that was much
smaller, the EMT 240; instead of a sheet of rolled steel, it used
gold foil. It was about the size and shape of a large exhaust
fan. Some DAWs and plug-ins can model that one too. It should
be noted that many plate reverbs, like their spring counterparts

often ran the recorder at 7.5 ips, doubling the delay time to
344 ms. This produced, if anything, a more muddled reverb
sound that suited Spector's "Wall of Sound" idea perfectly.
Digital reverb
In the 1980s the first digital reverb boxes appeared. Since the
state of the digital art then was pretty primitive, the reverbs were
too. They typically used low sample rates and bit depths, so
their sound was pretty grotty, but they offered a choice between
many reverb algorithms, including emulations of chambers and
plates. Many of them didn't offer control over the actual parameters of the reverb, but presented a series of presets.
The reverb programs built into modern DAWs work in similar ways, but they usually offer users the opportunity to tweak
the parameters, and save copacetic combinations as userdefined presets along with those created by the manufacturer.
These reverbs work by taking the original signal and calculating what will happen as it bounces between the walls of a
mathematically defined space, adding filtering and EQ to the
bounced signals to simulate absorption by different materials.
A good digital reverb will simulate the actions of thousands of
bounces, and you might imagine that this would mean a lot
of work for the computer's processor. You'd be right; reverb
plug-ins are notorious for hogging computer resources, and
having several instances of reverb going at once can cause a
computer's CPU to max out.

Come to think of it, playing is the best way to figure out
just about any audio software, DAW function, or plug-in.
Give yourself an afternoon, and save some of your experiments.
and even many chambers, are set up to work from a mono
input, though they may generate a stereo output.
Mixing it up
Record producers and engineers quickly discovered that
they could combine the delay produced by a slapbackgenerating tape recorder with fancier reverb devices like
plates, springs or even chambers. By adding a standard slapback delay of 172 ms (I told you to remember that number),
which fed the plate, spring or chamber, they mimicked the fact
that real-world reverb doesn't start reverberating right away,
but begins after the first reflected sounds hit the walls of the
room and your ears. This is called predelay.
One famous use of hybrid reverb, with a tape delay feeding
a chamber, was the Wall of Sound made famous by producer
Phil Spector. His reverb sounded different from everyone else's
for a couple of reasons. First, he fed absolutely everything in
the studio into the reverb mix, rather than just a few vocals and
guitars. (And there was a lot to feed; he would typically employ
several guitarists, both electric and acoustic, several backup
singers, and sometimes even multiple drum kits and bass players.) Second, while most producers ran the predelay tape
recorder at the standard professional speed of 15 ips, Spector
62

RECORDING SEPTEMBER 2016

At this point I'd normally tell you what the standard controls
are on reverb plug-ins, and suggest ways of tweaking them,
but here we run up against a barrier: there isn't a standard.
Different manufacturers have different ways of describing the
parameter controls on their reverbs. The best I can offer you is
the one parameter that every DAW and plug-in seems to offer:
Reverb Time. This is typically (but not always) defined as RT60,
or the length of time it takes the signal to drop by 60 dB from
its initial level.
So how do you learn to use a reverb function or plug-in in a
DAW? Open an audio file of the type you usually work on,
add the reverb, and start previewing. Call up some of the presets, and tweak the various parameters that your particular
reverb offers. The operative word is play: play with all the controls until you have a gut-level feeling what each one does.
Take notes if that helps.
Come to think of it, playing is the best way to figure out just
about any audio software, DAW function, or plug-in. Give
yourself an afternoon, and save some of your experiments. Be
a kid; try everything, including combinations you think won't
work. Some of them won't, but you'll have found out about
them, and if you're lucky a few of the hopeless combinations
will surprise you in a pleasant way.

Table of Contents for the Digital Edition of Recording - September 2016