Symetrix 258E, User Manual, Page: 19 / 46

528E
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On the other hand, if the levels within the 528E are too low to start with, using the equalizer for
boost may increase noise to unacceptable levels.
If levels are too low, increase the preamp gain (or the output level of the device feeding the line input).
Know What You Are Listening To
Low frequency boost may increase the level of some frequencies that cannot be heard, for one
reason or another. Many high quality microphones are capable of generating substantial output at
very low frequencies (below 50 Hz) which cannot be adequately reproduced by most monitor
speakers or headphones. Be aware that the true effects of low frequency boost may not be audible,
and may actually result in a “muddy” or distorted sound.
Use Wide Peaks, Narrow Dips
In general, the human ear prefers wide bandwidth peaks and narrow bandwidth dips. Boosting a
narrow bandwidth produces a sound usually perceived as “offensive,” while boosting wider
bandwidths (.7 octave or greater) usually results in a sound deemed “musical.” It has also been
observed that very few people will notice anything’s missing when a narrow bandwidth (.3 octave
or less) is cut, even when it’s cut as much as 30 dB. But, cut a wide bandwidth and the resulting
sound quality is often called “empty.”
Tuning the EQ/Notch Filter
To “tune” the equalizer, use full boost. For both boost and cut, the 528E’s parametric equalizer is
intended to be put to work on specific frequencies. To find a particular frequency “by ear” (the
method used by everyone who doesn’t have a real-time analyzer), turn the cut/boost control all the
way up to +15 dB (be very careful of feedback if you are monitoring on a loudspeaker!). Set the
bandwidth for about .3 octave (max CCW). Tune the frequency control until you distinctly hear the
part of the sound you wish to control. Then, adjust the cut/boost control for the appropriate amount
of change, and readjust the bandwidth control if necessary.
Equalizing for Speech
In broadcast, equalizers are often used to create a sonic personality for the station’s on-air talent. In
production applications, it is practical to write down each person’s settings. In broadcast applica-
tions (on-air), most stations try to find a single composite setting that works for all of their on-air
talent. If your station’s on-air talent is comprised of both men and women then finding a single,
compromise setting becomes more difficult. A possibly more workable solution might be to use a
single-D3 microphone (so it has proximity effect) and to vary the working distance to alter the low-
frequency response somewhat.
Some general thoughts on speech equalization:
1. Try to use wider bandwidths. Narrower bandwidths (1/2 octave and less) are less audible
(harder to hear) and are generally only useful for remedial work. Broader bandwidths are
less obnoxious, more pleasing sounding, and easier to work with (especially if you’re
boosting a range of frequencies).
2. Try to avoid massive amounts of boost or cut. If you’re only trying to impart a flavor (like
sprinkling salt and pepper on a meal), then 6-8 dB of boost or cut should be all that you
need.
3. A wide bandwidth cut is equivalent to a boost at the frequencies surrounding the cut.
4. A quick way to figure out what’s going on is to set the level of one band of the equalizer
to full boost (+15 dB), then switch to the frequency control and vary the frequency of that
band of the equalizer while listening to program material fed through the unit. This usually
makes quick work out of finding the region that you want to work on. Now reduce the level
setting to something tasteful.