Symetrix 258E, Руководство пользователя, Страница: 33 / 46

528E
31
Adding Dynamics, or “Punch”
By setting the expand threshold above the level of the program material, the 528E can be made to
behave like a linear expander (see Chapter 6). With this technique, the 528E can simultaneously
create a more dynamic feel, add compression, and reduce noise. Use this kind of processing for
special effects, and to increase the dynamic feel of percussive instruments like electric bass, snare
drum, rhythm guitar, etc.
Set the expander threshold above the signal level. The compressor/limiter is used to control peaks
(and with certain instruments like electric bass, to put in a little more “bottom” by creating extra
sustain). Set the comp threshold so the maximum compression is about 6dB with ratios below 2:1,
or 3dB with ratios above 2:1.
Since this kind of processing reduces overall output level, use the output gain control to bring
levels back up to normal.
High Level Stage Monitors - Dynamic Processing
Public address and sound reinforcement situations that require compression/limiting are often
plagued by feedback problems. Usually the “make up gain” used with compression causes an
overall increase in level which in turn, can cause feedback in the absence of signal, when the
compressor releases and brings the gain back up to normal.
The 528E’s interactive dynamics processor allows the use of large amounts of comp/limiting
without serious side effects. When compression is applied to “normal” signal levels, the compres-
sor returns to unity gain when the signal goes away. This action increases overall system gain. The
528E’s expander, on the other hand, decreases gain whenever signals fall below threshold. Careful
setting of the two threshold controls tells the 528E how and when to adjust the gain.
Stage monitors can be made much “tighter” with compression, but feedback problems often make
even gentle, low ratio compression impossible. The 528E’s interactive processor performs exceed-
ingly well in this situation, because the expander decreases gain to compensate for the gain
increase that results from compression.
Careful adjustment of the expander threshold control will prevent feedback in the absence of
signal, even with substantial compression. Note that in most cases the expander threshold must be
set higher than the compressor threshold.
1
An actualities cart is a recording (on a Fidelipac cart) of an actual broadcast. An aircheck by any other
name. Actualities carts are typically used to give someone else a warm fuzzy feeling.