Logic Compressor Auto-Release
Nov 2nd, 2019, 04:33
Regarding Logic's Compressor, Tedness writes: > One thing I didn't get ... is how the auto release functions in relation to the manual release setting... Short answer: With manual Release the compressor releases (stops compressing) at the set Release rate; with an auto-release the actual Release time is dependent on the audio signal, and so it varies with the audioâ€”in the case of the Logic Compressor, apparently varying around the manual Release setting. Longer description: Auto-release was often a feature inherent in the design of many older (vintage) compressors, due to the circuitry that controlled gain reduction. Probably the best-known example is the Teletronix LA-2Aâ€”the hardware unit that inspired the Vintage Opto model in Logic's Compressorâ€”which employed a light-based circuit to control compression. That circuit didn't offer manual control of the attack or release; those rates were based on the response of the optical circuitâ€”the electro-luminescent panel and optical attenuatorâ€”that determine the LA-2A's compression response. This kind of audio-based response is referred to as program-dependent, and it's a feature of many classic compressors. In the case of the LA-2A, the auto-release time is on the longer side, and is a staged responseâ€”faster at first, then slowing down, with the exact rate/response based on the audio signal. It's kind of like having the compressor optimize its response based on the particular audio signal, and this program-dependent response is generally acknowledged to be a significant component of the "smoothness" the LA-2A is known for. A compressor may have a program-dependent release but still provide a manual Release controlâ€”in some cases the actual response may be based around the manual settings, but still vary with the audio signal, while in others enabling auto-release may override any manual controls, for a completely automatic release behavior. Logic's Compressor models all seem to take the former approachâ€”the auto-response appears to vary based around the manual setting of the Release control, even if the original had no such control. If the Logic Compressor offers a manual control that wasnâ€™t present on the originalâ€”like the Vintage Opto modelâ€”for more classic release behavior Iâ€™d set it at something close to the nominal release rate of the originalâ€”maybe around a second or so for the Opto modelâ€”and fine-tune by ear. Generally, if you're looking for smoothness and transparency, enabling auto-release would probably be a good choice, while if you were going for more of a compression "effect"â€”like deliberate pumping to fatten up drumsâ€”then you might be able to dial up a more pronounced effect with auto-release off. With Logic's Compressor, since the controls often exceed the range of the controls on the original units being modeled, a little experimentation would be in order.