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2. Using the SX201
Care must be exercised when using equalization. The general
precautions are:
2.1 Beware Distortion and Noise
When a frequency or group of frequencies are boosted, the overall
operating level is boosted as well. For example, 12dB of boost (no
matter what the frequency) increases the SX201's output level
12dB. This kind of boost will reduce headroom by 12dB in every
circuit from the SX201's own line driver to the last device in the
signal chain (amplifier, tape machine, mixer, or what have you).
Unless signal levels are very low to begin with, the SX201's input
attenuator will probably have to be turned down to compensate
for increased levels when the equalizer is used for more than 6dB
or 8dB boost.
On the other hand, if the levels within the SX201 are too low to
start with, using the equalizer for boost may increase noise that
already exists in the signal to unacceptable levels. If levels are
too low, reduce input attenuation (by turning the input
attenuator control clockwise) or increase the input level (by
increasing the output level of the device feeding the SX201).
2.2 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 50Hz) 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.
2.3 Use Wide Peaks, Narrow Notches
In general, the human ear prefers wide bandwidth peaks and
narrow bandwidth notches. 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 30dB.
But, cut a wide bandwidth and the resulting sound quality is
often called "empty."
