I’m having a hard time understanding the sidechain knob in the CLA Compressors.
In the CLA-2A manual, it says, “HiFreq increases voltage amplifier gain in the peak reduction circuit, for frequencies above 1 kHz, leaving lower frequencies unaffected. When set to Flat, the CLA-2A will provide equal
reduction to all frequencies. The more you move away from the Flat position, the less sensitive the compressor is to lower frequencies, resulting in less compression. This control may also be used as sort of a de-esser.”
In the CLA-3A manual, it says, “The more you move away from the Flat
position, the more sensitive the compressor is to higher frequencies, resulting in heavier compression. This control may also be used as sort of a de-esser.”
Hm,m. Both describe it slightly differently, and neither are what I understand a side-chain to do. Could someone please clarify?
My understanding is that the side-chain should basically apply a high-pass filter, not to the output of the compressor itself, but to the incoming signal that will trigger the compressor. I understand that to mean that the compressor will then not be triggered so easily by the low-end stuff, which can throw things off cuz of all the energy down there. It would be triggered by the higher frequencies, cuz they are elevated and hit the compressor first. So the compressor, for example, will not be so much triggered by the kick or bass for example (so no pumping) but by, say, the highe frequency guitars, vocals, etc., because they’ll hit the compressor first.
So, my understanding is that side-chaining is about the frequency of the signal that triggers the compressor only. Meaning that after it’s triggered it’ll be applied equally to the full frequency spectrum, correct? So, I’m thinking the CLA-2A manual is incorrect when it says, “When set to Flat, the CLA-2A will provide equal reduction to all frequencies.” Well, I mean, that’s kind of correct but misleading: once triggered the compressor will always provide equal reduction to all frequencies, no? Similarly, it’s not about “leaving lower frequencies unaffected.” It’s not about what’d coming out of the compressor, but what’s going into it.
If you want to apply compression only to high frequencies (which is different than a side-chain), you’d use a multi-band compressor (or maybe a de-esser which is pretty much a special application of a MB Compressor).
I’m thinking the CLA-3A manual is closer, but still not quite correct. It’s not that it’s more sensitive to high frequencies, but that that the sidechain increases the elevation of the high frequencies over the low, so that they would trigger the compressor first.
Please tell me I’m correct. Just trying to understand this!