Instrument or Line Level in Comp Block

j20056

j20056

Member
if I put a Comp block right after Input1 (Guitar), do I need to select Instrument in the Input Level drop down on the right of the block config? I would have thought everything is line level once in the AxeFX grid? I lose a lot of signal level when selecting Instrument. I guess I'm unsure what to do, sounds sems to be the same, just lower volume with Instrument.
 
I had not given this parm much thought either, but this reminder of it gets me keen to revisit having a global subtle end-of-chain compressor in my presets (been a bit frustrated in the past trying this as I could not find a global settlng for the compressor to yeild a subtle final "glueing" affect for any given preset).
 
dr bonkers said:
Perhaps for the non techie user, they should be labeled "before amp level" and "after amp level ".

There would be few if any confused by such labels.
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I think many would be confused. “After amp level? I didn’t even do an amp level!”
 
fetishfrog said:
Line Level is industry standard and makes sense for running line level signals into the compressor block.
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Line level gets to be wacky thing on a grid in a modeler.

For example, one can insert effects between the out of the power amp of the amp block and the cab. That should smoke outboard gear, but it doesn't in the Axe-FX.

It's not a true effects loop line level or instrument level since it's not between the preamp and power amp like most real amp loops.
 
I don't find the labels confusing at all, and the manual is quite clear - the challenge with compressors, for me anyway, has always been getting a good handle on what they do to the sound at various settings combinations - I want to revisit this particular parm as I'd kind of ignored it in the past when deploying compression before or after the amp stage (maybe explaining some of my challenges)
 
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I think the heart of the matter is: what the heck does it do? :) I don't understand the before/after amp block comment since the amp block generally doesn't have much effect on the signal level in Axe-FX presets. It seems to change the interpretation of the threshold in some way, but I don't understand how that would relate to the detector.
 
GlennO said:
I don't understand the before/after amp block comment since the amp block generally doesn't have much effect on the signal level in Axe-FX presets.
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Even with no Amp block on the grid, it's still instrument level at input 1 & line level at output 1 right?
 
GlennO said:
I think the heart of the matter is: what the heck does it do? :) I don't understand the before/after amp block comment since the amp block generally doesn't have much effect on the signal level in Axe-FX presets. It seems to change the interpretation of the threshold in some way, but I don't understand how that would relate to the detector.
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The amp block can boost the level a few dB, but it also tends to add a fair bit of its own tube compression as well, especially on high gain sounds. I'd expect the signal directly from the guitar to be a bit lower level, but more dynamic. I'm not exactly sure what the instrument/line option actually does but it seems to maybe scale the threshold of the compressor. Comparing a synth sine wave into two parallel Comp blocks with identical settings except for the instrument/line setting seems to yield a few dB less compression on the Line setting, making me think the effective threshold is raised.
 
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Not sure if this is accurate, but I always thought of this as the difference between a compressor pedal and a rackmount. Pedals usually have less headroom than rackmount, which would effectively raise the threshold a little as well as making for a slightly "cleaner" sound, all other things being equal. Like I said, this may not be accurate and there are probably other things going on, but this is just how I've differentiated these settings for my own use.
 
mr_fender said:
yield a few dB less compression on the Line setting, making me think the effective threshold is raised.
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It seems to be a 12 dB threshold offset on the studio types, and an offset of 3 (apparently 1 unit = 4 dB) on the Compression parameter of pedal types. So, nothing that couldn't be accomplished with an adjustment to those parameters, plus block level if makeup gain is on. The Tube compressor type seems different; changing only the threshold won't match what the line/inst switch does. I'd guess it might be both a threshold and compression parameter offset but I only spent about 2 minutes checking this out just now.
 
Zedhed said:
Even with no Amp block on the grid, it's still instrument level at input 1 & line level at output 1 right?
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Typically, yes. Any block can potentially adjust the signal level of course, but usually the amp block doesn’t change the level much, so it’s hard to make sense of the line/instrument terminology. Mr Fender might be right and it doesn’t have anything to do with instrument/line level at all, and instead changes the behavior so it works better with a signal that has already been compressed.
 
With all the speculation about instrument vs line level and before amp vs after amp regarding compression (and the types) .. it would be cool if Cliff chimed in, and / or you need to do your own research and experiment.
I really only use some (like 3:1) in clean sounds, or with a little edge / dirt tones. I like my dynamics .. mostly.
 
GlennO said:
I think the heart of the matter is: what the heck does it do? :) I don't understand the before/after amp block comment since the amp block generally doesn't have much effect on the signal level in Axe-FX presets. It seems to change the interpretation of the threshold in some way, but I don't understand how that would relate to the detector.
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Exactly! This has always been my issue with it.
 
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