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Live sound reinforcement can be a challenging business. Look what we have to deal with: The
guitar player turns up to 11 and still complains that she can't hear herself. The podium speaker
points the mic at his sternum and mumbles, drowned out by the chatter of people eating dinner, in
a boxy hotel convention room. The rock singer asks for - no, DEMANDS - a monitor level loud
enough to hear over a drag race in a hurricane. The minister clips on the lavalier mic and wan-
ders around while preaching, sometimes right past the speaker cabinet...
As an antidote to premature aging and undue stress, we at Sabine have dedicated ourselves to
simplifying the demands of live sound amplification by creating adaptive equipment that handles
some of the tedious (but important) mixing chores automatically. This allows sound engineers to
concentrate on making a mix sound good instead of dealing with acoustical problems!
The POWER-Q's features are designed to help you achieve two important goals in sound rein-
forcement: getting more gain before feedback , and more clarity and definition in the sound . At the
risk of sounding like a drill sergeant, let's call this the desire to be LOUD and CLEAR.
At least two bad things happen in the pursuit of loudness (putting aside
the deafness potential): feedback and lack of headroom.
Let's consider headroom first. The dynamic range of DSP is limited by the word length of an
individual datum: The more bits in a word, the greater the dynamic range. The POWER-Q offers
24 bit resolution and a dynamic range spec of >110 dB (with ClipGuard™). Plus, our ClipGuard™
Adaptive Clip Level Control system is designed to make it all but impossible for our units to clip
digitally; so if you're hearing distortion in your system, it's not likely coming from your POWER-Q,
because we've taken steps to prevent that. (Note: Make sure the FBX TURBO setup mode is off
before your program begins; see section 11.2.) Likewise, the compressor/limiter built into the
POWER-Q will raise the average gain level of your mix while protecting your speakers from hot
shot sound engineers whose goal in life is to explore the extremes of speaker cone flexion. All of
these functions are designed to maximize your gain without distortion.
Maximizing gain would be a far simpler matter if it weren't for the problem created by adding gain
to a microphone in the presence of a speaker, which in turn reproduces the mic's sound, with the
mic in turn amplifying its own input, and so on. At some point, at least one frequency will regener-
ate. This is techno-speak for that dreadful ringing sound commonly known as feedback. The
nature and severity of the feedback will depend on the sound system and the acoustical environ-
ment, but feedback generally will occur before you reach the limits of your potential amplification.
This means that the most likely volume limitation of your sound system is not the power of your
amplifiers or the size of your speakers, but the threshold of feedback.
Enter the Sabine FBX. In the pre-FBX dark ages, feedback was often controlled by passing a mix
through a graphic equalizer and pulling out frequencies as close as possible to the ringing feed-
back. While this technique can reduce feedback, it also reduces the sound quality of the overall
mix. The one octave-wide filters of a third-octave equalizer (you read that right—the filters are
usually an octave wide, spaced on overlapping third-octave centers) are far too clumsy and
inaccurate to target feedback specifically. You don't shoot a mosquito with a shotgun or do brain
surgery with hockey gloves. Shotguns, hockey gloves and graphic equalizers are valuable tools,
but only in the right applications. A graphic EQ is great to shape the overall sound of your mix
(and that's why we've loaded your POWER-Q with two), but when you use it to control feedback
by pulling down EQ sliders, you're also pulling out a big chunk of audio that is NOT feedback.
An FBX filter automatically detects feedback within a 1Hz resolution, places a tenth-octave wide
filter on it, and pulls down the level only as far as necessary to get rid of the feedback at a given
gain level. It is far more accurate in identifying and eliminating feedback and far less destructive
to your sound than even the best graphic equalizer. Plus it finds the feedback automatically in a
fraction of a second. You'd need to drink A LOT of coffee to react that quickly.
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