API 2500 - 4.1.1 Threshold Control; 4.1.2 Attack Time; 4.1.3 Ratio Settings

50
th
Anniversary 2500 Bus Compressor API
11
4.1 Compressor Section Controls
4.1.1 THRESHOLD
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
4.1.2 ATTACK
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)
4.1.3 RATIO
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