528E
16
kHz frequently gives an apparent increase of 3 dB to the overall signal.
Attenuating the 5 kHz range on instruments gives a “transparent” quality to the sound, providing,
of course, that the remainder of the signal is otherwise wide range. Microphones having a dip in
this region lack the “punch” or “presence” to which we (Americans) are accustomed.
Brilliance
Unvoiced consonants attributed to tooth, tongue and lip sounds are high in frequency, and reach the
10 kHz range. These frequencies account for some clarity and most brilliance, even though they
contain less than 2% of the total speech energy. This also holds true for musical instruments; espe-
cially percussion. Boosting or cutting this range affects clarity and naturalness. In speech, the 9th
and 10th octaves impart intimacy although too much emphasis can make secondary speech sounds
(lip smacking, etc.) objectionable (a good case for a expander).
Some microphones having a rise at the higher fre quen cies (especially omni microphones) benefi t
from some attenuation in this region. Those microphones having under damped diaphragms may
ring at these frequencies, causing an annoying sibilant distortion on speech. On musical forms us-
ing hand percussion, boosting this range frequently results in an astonishing and pleasing feeling of
clarity.
Conclusions
When the article containing the above excerpts was written (probably around 1963), stereo was just
becoming a commercial reality (you could still purchase mono and stereo versions of an LP and
there were still more FM stations broadcasting in mono than stereo), and as many mixers contained
rotary mix pots as those that used slide pots. The value of individual channel equal iza tion was
known, but it was both technologically and fi nancially prohibitive. The article concludes thusly:
“With the advent of stereo and three-channel recording, nearly three times the equipment, with
more elaboration, seems indicated, and expansion of console area in the horizontal plane offers the
only direction in which to proceed. But a single engineer has arms only so long.”
How times have changed!
Using the Parametric Equalizer
Great care must be exercised when using equalization. The following paragraphs give some general
hints and pre cau tions for using the 528E’s parametric equalizer (or any other equalizer, for that
matter).
Beware of Distortion and Noise
When a frequency or group of frequencies are boosted, the overall operating level is boosted as
well. For example, 12 dB of boost (no matter what the frequency) increases the 528E’s output level
12 dB (at that frequency). This kind of boost reduces headroom by 12 dB in every circuit from the
528E’s own line driver to the last device in the signal chain (transmitter, tape machine, or what
have you). Unless signal levels are very low to begin with, the 528E’s output gain will have to be
reduced to compensate for increased levels whenever the equalizer is used for boost.
The Clip LED in the Output LED meter monitors levels in the equalizer as well as at the output of
the 528E. If the Clip LED glows, try switching the equalizer to Bypass. If the LED still glows, re-
duce the setting of the Output Gain control. If switching the equalizer to Bypass eliminates the clip
indication, then the input level must be reduced via the Mic Gain control or by lowering the level of
the line input.
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).
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