dbx 128 - WHEN TO USE COMBINATION APPLICATIONS; Noise Reduction Plus Expansion; Noise Reduction Plus Compression

WHEN TO USE COMBINATION APPLICATIONS
You can simultaneously use the 128’s tape noise reduc-
tion circuitry plus any one of the following: expansion,
peak unlimiting, compression or peak limiting.
When to Use dbx Ii Tape Noise Reduction Plus Expansion
By recording and playing back a program with dbx I|
tape noise reduction and then expanding it, you can end up
with a program that actually has lower noise and better
dynamic range than the original. This is especially effective
on noisy phonograph discs.
When
expanding
or
peak
unlimiting
a
program
that
has
been
recorded
with
dbx
II,
the
128’s
expansion
circuitry
should
come
after
the
dbx
I!
tape
noise
reduction
circuitry
(push
the
POST
button).
This
allows
the
dbx
tape
noise
reduction
circuits
to
properly
decode
the
program,
before
the
expansion.
It is not necessary to use the 128’s expansion circuitry
when playing a dbx-encoded disc, since the encoded disc
already has an extremely wide dynamic range. To avoid
over expansion, always press the PRE button and set the
COMPRESS/EXPAND control to the “1.0” (12 o’clock)
position when playing a dbx-encoded disc.
When to Use dbx II Tape Noise Reduction
Plus Compression
Normally, when making a recording with dbx Tape
Noise Reduction, additional compression is not necessary.
Compression might normally be used to restrict dynamic
range, and to “get the program on the tape,’’ but dbx
encoding alone overcomes the dynamic range limitations
of recording tapes. If you use compression plus dbx tape
noise reduction, the compression would primarily be for
special effects purposes.
When playing a tape which has been recorded with
dbx II tape noise reduction, or when playing a dbx-
encoded disc, you can use the 128 for peak limiting
(above threshold compression).
When adding compression or limiting while playing back
a dbx-encoded tape or a dbx-encoded disc, the 128’s com-
pression circuitry should come after the 128’s tape noise
reduction circuitry (press the POST switch).