dbx 122 - Page 26

HINTS TO GET THE MOST OUT OF
dbx NOISE REDUCTION
Mixing
Individual channels which have been dbx-encoded can-
not be mixed together unless they are first individually
decoded. In fact, encoded tapes must be decoded before
limiting, equalization, or any other special signal processing
anges).
levels (as displayed on your tape
will be somewhat lower with the dbx
2, and minimum levels will be higher.
J meter on the tape recorder will not
(if any) on the preamp or mixer.
ie 2:1 compression. The average
.e tape recorder should generally be
-10VU and —3VU when recording
iis level allows plenty of headroom
ger of tape saturation, and it
es adequate separation from the
to increase record levels to “take
d level (High Output Low Noise)
‘sirable to retain standard record and
extra headroom for truly accurate
transient respurss. +e extra few dB of recorded level are
not necessary because dbx processing avoids residual tape
noise even with standard tapes. We recommend the new
smooth-surfaced tapes (calendered tapes} which have
inherently lower noise.
Bias, Equalization and Alignment
Hiss level in tape recording is a function of the recorded
signal level as well as bias level. In order to minimize tape
modulation noise, it is important that the tape machine be
properly biased for the particular tape used. If your tape 25
machine has bias and equalization switches or adjustments,
experiment to find the settings that yield the lowest tape
modulation noise and the best frequency response with dbx
encoding and decoding. * Proper head alignment is also
important because the 2:1 expansion of the dbx decoding
can exaggerate any frequency response errors in the tape
record/playback process. In addition, always keep your
tape heads clean and demagnetized to avoid extra noise
and distortion. Correct bias, equalization and alignment
are important for any recording, but are especially
important to get the most out of recording with dbx
processing.
Effects
When recording with dbx I! tape noise reduction, use
limiting and compression for special effects only. The dbx
encoding process makes routine limiting and compression
completely unnecessary. (As stated in the hint “Mixing,”
any such signal processing would be done before enéoding,
if at all.) :
Microphones and Pickups
When making live recordings from microphones or
instrument pickups, the signal level must first be pre-
amplified before being applied to the dbx’s RECORD
INPUT jacks. A low noise preamplifier should be used to
take full advantage of the noise reduced recordings. if your
tape machine has mic preamplifiers, these cannot be used
because they would bypass the dbx encoding. Some stereo
receivers have mic preamps, which may be used since they
come before dbx encoding, and there are relatively inex-
pensive battery powered mic preamps, too.
Coughs, shoe scuffs, and similar sounds which may
*See Page 32 for a discussion of tape modulation noise.