Compressor Section Controls; Threshold; Attack; Ratio - API 2500 Operator's Manual

4.1 Compressor Section Controls

4.1.1 THRESHOLD

4.1.2 ATTACK

4.1.3 RATIO

50 th Anniversary 2500 Bus Compressor
THRESHOLD: Sets the level at which compression begins
• Continuously variable range between +20dBu and -20dBu
Threshold LED: Illuminates when the input audio crosses the level set by the
THRESHOLD control
• Red LED illuminates when input level crosses the set THRESHOLD
ATTACK: Sets the time it takes the compressor to react when the level
exceeds the set THRESHOLD
Fixed attack times: .03, .1, .3, 1, 3, 10, and 30 milliseconds (m/sec)
•
RATIO: Sets the ratio of input vs. output levels for signals that fall
above the set THRESHOLD
• Fixed ratios: 1.5:1, 2:1, 3:1, 4:1, 6:1, 10:1, and ∞:1 (x:1)
• Compression with ratios of 10:1 or greater is generally
considered to be limiting
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API