Burning the Midnight Monitor Oil
by Eddie Cilletti
have improved considerably during the past 20 years. Distortion is lower,
power handling is higher, and bandwidth is wider. Despite the improvements,
however, monitoring systems are still the weak link when compared to any
electronic hardware, digital or analog. The obstacle is not the lack of
progress but the fact that the largest collection of variables ever thrown
at transducer technology is called “a room with stuff in it.” This obstruction
can make it difficult to assess the health of your monitoring system.
of talk about the sound of outboard gear. From converters to
mic preamps, equalizers to compressors, these are devices that can be
fear of destruction and can be appreciated for what can be rather subtle
nuances. There is nothing subtle about monitoring systems.
A cabinet at the near-field position will sound much different on a bookshelf,
on the floor or next to an identical system. All this before we
drive ’em hard, blast ’em with feedback or accidentally remove the reference
clock from a piece of digital gear. Ouch!
Other “room interaction”
issues will reveal themselves when panning any sound source from left
to right (or right to left, in some parts of the world). Try this test
with kick, snare, vocal, crunchy electric guitar or pink noise. If differences
were noticed, especially at low frequencies, would you suspect the monitors
or the room? You can swap power amp channels easily enough—crossovers
and drivers require a little more effort. Be sure to exercise every connection
between the console and each speaker component. If nothing changes, the
problem is with the room and/or cabinet placement.
polarity is critical—an out-of-phase subwoofer will create a “hole” at
the crossover region rather than a smooth transition. Most times you simply
want the subwoofer to pick up where the satellite rolls off. For greater
flexibility, get a subwoofer that includes a crossover for itself as well
as the “satellite” speakers. There will always be phase shift in the crossover
region—it’s the inherent nature of the filters—so look for the ability
to fine-tune the phase, in addition to polarity.
Anytime a monitor chart shows near-flat frequency response, you are looking at the soft-focused Reader’s Digest version. It’s way more complex than that! Monitors are measured in an anechoic chamber, not in a studio environment, where each boundary—wall, floor, console—can increase low-frequency response. A freestanding monitor with no nearby boundaries will have less bass than a soffitt-mounted monitor, assuming the environment is well-designed.
Each driver in a monitoring
system is much more like a stringed instrument than you might have ever
imagined. I could show you charts for days, but Fig. 1 gets to the crux
of the biscuit with a down and dirty crosscut view. Like a guitar that
was “in tune when you bought it,” a driver starts out with a resonant
frequency and a series of complex harmonic overtones that constitute its
sonic fingerprint. A loudspeaker played hard will eventually go flat,
shifting the resonance downward and permanently altering the fingerprint.
with permission from Mix Magazine, May 2000