BSS Audio
DPR-402 User Manual v3.0
Page 5
1
.2 Compressors and Limiters
Compressors and limiters have closely related effects, and in general a limiter will
reduce gain very strongly once a certain level has been reached, whereas a
compressor will act gently, but over a much wider range of volume levels.
A limiter will continuously monitor program levels, but only commence to reduce
gain once the level has exceeded a preset amount. This point is called the
threshold level. Any program level in excess of the threshold will immediately be
reduced to this threshold level.
A compressor will also continuously monitor the program and has a threshold
level. However, program signals in excess of this threshold will be progressively
reduced by an amount (ratio) depending on the degree to which it initially exceeds
the threshold. Generally, threshold levels for compressors are set below the normal
operating level to allow them to reduce the dynamic range of the signal gradually,
so that they are acceptable to following equipment. For limiters, the threshold
point will be set above the operating level in order to provide a maximum level for
signals to following equipment.
2 The effect of Compression on sound
2
.1 Compression
Consider an input signal which is applied to two units, one having its threshold
point set 10dB higher than the other
(See figures 2.1 a/b)
. Since the compressor
only affects signals that exceed the threshold level, that in figure 2.1a will be more
affected than that in figure 2.1b.
