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Post by M57 on Dec 1, 2018 12:07:38 GMT -6
I was wondering why I wouldn't want to use a single channel of a stereo buss compressor like the Audio Scape for any regular compression duties? Which of course opened up a can of other questions.
How does a stereo buss compressor like the Audio Scape work? What triggers the compressor? Is it dependent on the sum or average threshold of the two channels, or perhaps the higher of the two? (<<-this is how ignorant I am about it) Or does it perhaps look independently at both of them? Regardless, do all parameters then function independently? ..attack, release, amount of compression, etc? In other words, is a buss compressor simply two completely independent compressors that share a single set of settings?
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Post by Tbone81 on Dec 1, 2018 12:15:34 GMT -6
It’s my understanding that Different compressors handle the side chain (source) differently. There’s no single way.
Also, it’s important to note the difference between stereo compression and dual mono compression. Many stereo compressors can do both. Dual mono compression acts like two separate compressors on each channel, each with the same exact setting. They compress independently of each other. Stereo compression uses some method of “adding” the left and right source together, and using that signal to trigger compression, with both sides compressioning together in sync. Make sense?
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Post by M57 on Dec 1, 2018 12:26:32 GMT -6
Sure, I think so.. Dual mono is two independent compressors. So it sounds like with "stereo" compression, it's unlikely that a single channel would work - though I suppose you could split the signal into both inputs such that the side-chain sees the same thing - then just use one output.
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Post by Deleted on Dec 1, 2018 12:48:12 GMT -6
Yes, there are many ways of implementing the linking of the channels. Impossible to use a single channel for stereo compression by its very definition, unless you run the L & R channels through it one after the other and then line up the waveforms, or use an M/S matrix to just compress the sum or difference, before putting them back together.
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Post by notneeson on Dec 1, 2018 12:59:10 GMT -6
The Audio Scape, or the Stam for that matter should be fine for mono duties using one side. Try 'em on bass drum.
If you're the worrying type, just send the same mono signal to both inputs and capture one side for mono return.
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Post by matt@IAA on Dec 1, 2018 16:24:17 GMT -6
I think most VCA compressors should work just fine as “mono” with signal applied to only one channel. The sidechain works by using a circuit that has a fixed in to out relationship, so a certain voltage on the input sends a certain voltage out. That output voltage is sent to the VCA as a control voltage, and the VCA attenuates (or amplifies) based on that control voltage. On some designs there is an RMS level detector upstream of the sidechain that shares a timing circuit and has only one output - so the amount of attenuation is based on the power sum of both channels. That style should work fine because the RMS / power sum of one channel by itself is the same as one channel plus zero (other channel no signal). But... just try it, use a tone generator and send a fixed level in and see what comes out.  |
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Post by ragan on Dec 1, 2018 16:33:55 GMT -6
I've always liked VCA comps on acoustic guitar and piano.
No reason you can't use a bus comp for non-bus duties or send your mix through a pair of whatevers. TP "Wildflowers" went through a pair of 1176s. Whatever gets a sound that puts a smile on your face.
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Post by Blackdawg on Dec 2, 2018 0:05:23 GMT -6
Dual Mono's compression is not the same as stereo compression.
Stereo compression functions in two ways are you previously state. Either the sidechain is summed to mono or it is stereo and listens to the L and R ch seperately. Both sound very different. Some SSL clones come with both versions of this form of side chain so you can pick. Mono will of course clamp down on signals common to both L and R. So pretty much whatever you've panned center the compressor is going to grab more. This can be annoying if you have a big kick, loud bass or vocal sound. Stereo will be more forgiving. Some DIY version call this mode Turbo mode.
The Audio scape and the Stam MKII both do this, its the SC switch on the AC lets you pick the Stam is just stereo as it is generally more preferred.
You can certainly use a "buss compressor" anywhere in your mix. I love using an SSL style VCA comp on my drum bus and a opto for parallel compression, usually LA3A set.
You can also feed a mono signal into one channel of it and use it that way. However two separate ones might not work so well.
Dual mono compression is just that. Two totally separate devices. So while yes a Stereo compressor in Stereo side chain mode is similar. Its not quite simply for the fact the likely hood of two compressors sounding the same and getting the dials exactly the same(threshold, make up gain, ect) is not that likely. Where as it going to be much closer to matching in an actual stereo unit.
Otherwise, it is the same idea.
So yes! use it where ever you want and can! there are no rules! If it sounds good..it is good!
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ericn
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Post by ericn on Dec 2, 2018 21:41:16 GMT -6
A stereo buss comp should work fine as a mono compressor, do pay attention to how your stereo comp detector circuit works, some key off a single ch.
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Post by cowboycoalminer on Dec 3, 2018 21:15:34 GMT -6
I've used stereo comps in mono many times with success. Just a matter of using our ears like anything. The 4k models are great on vocals. Very quick when set properly.
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Post by svart on Dec 4, 2018 12:19:28 GMT -6
I was wondering why I wouldn't want to use a single channel of a stereo buss compressor like the Audio Scape for any regular compression duties? Which of course opened up a can of other questions. How does a stereo buss compressor like the Audio Scape work? What triggers the compressor? Is it dependent on the sum or average threshold of the two channels, or perhaps the higher of the two? (<<-this is how ignorant I am about it) Or does it perhaps look independently at both of them? Regardless, do all parameters then function independently? ..attack, release, amount of compression, etc? In other words, is a buss compressor simply two completely independent compressors that share a single set of settings? I don't know how the AS is built, but generally a "stereo" version has some degree of both the L and R signals acting upon the other side. You can have full summation of the Land R like the original GSSL had, or varying degrees of separation. As mentioned in the thread, dual mono is exactly what the name describes. Sometimes the compressors will have separate controls, sometimes not. Sometimes dual mono will have a stereo "link" which just ties the sum of the sidechains together. Personally I like dual mono so I can use them separately if needed. I mix the master bus with the amount of stereo spread I want already, so dual mono will "see" the right amount of the opposite side already. |
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Post by Blackdawg on Dec 4, 2018 13:39:58 GMT -6
I was wondering why I wouldn't want to use a single channel of a stereo buss compressor like the Audio Scape for any regular compression duties? Which of course opened up a can of other questions. How does a stereo buss compressor like the Audio Scape work? What triggers the compressor? Is it dependent on the sum or average threshold of the two channels, or perhaps the higher of the two? (<<-this is how ignorant I am about it) Or does it perhaps look independently at both of them? Regardless, do all parameters then function independently? ..attack, release, amount of compression, etc? In other words, is a buss compressor simply two completely independent compressors that share a single set of settings? I don't know how the AS is built, but generally a "stereo" version has some degree of both the L and R signals acting upon the other side. You can have full summation of the Land R like the original GSSL had, or varying degrees of separation. As mentioned in the thread, dual mono is exactly what the name describes. Sometimes the compressors will have separate controls, sometimes not. Sometimes dual mono will have a stereo "link" which just ties the sum of the sidechains together. Personally I like dual mono so I can use them separately if needed. I mix the master bus with the amount of stereo spread I want already, so dual mono will "see" the right amount of the opposite side already. Audio Scapes is stereo operation FYI. |
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