Upward compressors?

[MogwaiBoy]

Almost any compressor can do upwards compression - it's just a matter of having the compressor clamped - deep threshold so the signal spends most of the time in gain reduction - with a large amount of makeup gain to match.

With the signal spending most of its time below the threshold (in large gain reduction+makeup), then, when the signal goes above the threshold (ie: quiet sections), the release transfer brings the volume back to normal signal level (which is louder), creating upward compression for the quiet sections. The timing of the release controls the onset.

Or, in simpler terms... parallel compression does the same or a similar thing (parallel compression "is a form of upward compression").

Sorry, Bob Katz explains this much better in his book 'Mastering Audio: The Art and the Science'.

[bmanic]

You are somewhat correct (just like Bob Katz is only somewhat correct). The actual mathematical transfer curve of the dynamics are slightly different. In the real world though, that difference is very seldom heard (unless you do over the top processing, then it can become obvious).

Also, the harmonics and amount of harmonics produced will differ. A compressor with fast attack and "clamping down/following the wave front" will produce far more harmonics than upwards compression where you get into the upwards stage after a slower release. Even if your release is fast, the upwards compression has a sort of built in "hold" stage as long as the signal doesn't cross the threshold, simply boosting everything below it.. thus again minimizing the creation of harmonics. So there will be subtle tonal differences in the various approaches.

[Havok]

I usually go to Kilohearts Dynamics for upwards compression, nice and simple, quick to use & easy to understand

https://kilohearts.com/products/dynamics

[shkr]

Almost any compressor can do upwards compression (...)

In theory yes, but following this logic we can say that every compressor can sound like every other one it's just a matter of getting speed controls and curves right. Upward compressor just like downward compressor can be tuned in a very specific way that can be really hard to emulate with different tools.
Besides we want to make our lifes easier not the other way round. For example we use transient shapers because they are faster and easier than tuning expansion.
The same with upward compression - for example it is just so much easier and faster to use OTT. Because when it works it works or we can move on and reach for other tools.
Nimble tools argent compressor I mentioned is created for upward mayhem and has some tricks up its sleeves. Good luck trying to emulate such behavior with typical downward compressor. But of course it is a one trick pony. Aggro pony

[MogwaiBoy]

You are somewhat correct (just like Bob Katz is only somewhat correct). The actual mathematical transfer curve of the dynamics are slightly different. In the real world though, that difference is very seldom heard (unless you do over the top processing, then it can become obvious).

Also, the harmonics and amount of harmonics produced will differ. A compressor with fast attack and "clamping down/following the wave front" will produce far more harmonics than upwards compression where you get into the upwards stage after a slower release. Even if your release is fast, the upwards compression has a sort of built in "hold" stage as long as the signal doesn't cross the threshold, simply boosting everything below it.. thus again minimizing the creation of harmonics. So there will be subtle tonal differences in the various approaches.

Yep! With the compressor mostly in gain reduction - thus being a non-linear process - the harmonic signature will be different.

But a lot of dedicated "upward compressor" plugins work this way, and are simply workflow-optimized for it. For example Flux have a whole suite of up/down/expand/de-expand plugins... that could all be done with one powerful plugin, if you know how each type of compression works. I know you are a pro at this so sorry if this sounds like MogwaiBoysplaining

[MogwaiBoy]

Almost any compressor can do upwards compression (...)

In theory yes, but following this logic we can say that every compressor can sound like every other one it's just a matter of getting speed controls and curves right. Upward compressor just like downward compressor can be tuned in a very specific way that can be really hard to emulate with different tools.
Besides we want to make our lifes easier not the other way round. For example we use transient shapers because they are faster and easier than tuning expansion.
The same with upward compression - for example it is just so much easier and faster to use OTT. Because when it works it works or we can move on and reach for other tools.
Nimble tools argent compressor I mentioned is created for upward mayhem and has some tricks up its sleeves. Good luck trying to emulate such behavior with typical downward compressor. But of course it is a one trick pony. Aggro pony

Not disagreeing with anything you say above. Totally agree - I have a huge compressor collection and although "in the mix" many can be made to sound very similar, there are often individual characteristics in behaviour that set each apart.

The compression we are talking about literally means "dynamic range reduction" - I think we can all agree on that - and there are a lot of ways to achieve that... for instance limiting is dynamic range reduction, therefore limiting is compression, albeit an extreme form of it.

[Ploki]

Idk - I don’t get the same “smack” from parallel as i do with upward.
Also I don’t get all the noise lol.

Transfer curve is not quite the same.

[SeBaer]

[...] upward compression and downward expansion [...]

okay, nevermind, I guess I can't tell all the terms apart....

[jBam]

Aberant DSP Shapeshifter and Eventide Omnipressor if i wanna get whacky and Pro MB for clean.

+1 omnicompressor if you want "obvious". It can be pretty mental how far you can push it - great parallel on drum bus or breaks (for me) for emphasised breathing effect. Defo needs some additional attention to clean up though (a few snappy spikes).

[FapFilter]

[...] upward compression and downward expansion [...]

okay, nevermind, I guess I can't tell all the terms apart....

no problem, it can be confusing…
here's my take trying on explaining as simple as i can:


DOWNWARD COMPRESSION (ratio > 1:1) = normal compressor. reduces dynamic range by making the loud part ABOVE the threshold quieter

UPWARD EXPANSION (ratio < 1:1) = expander. increases dynamic range by making the loud part ABOVE the threshold louder

DOWNWARD EXPANSION = noise gate. increases dynamic range by making the quiet part BELOW the threshold quieter

UPWARD COMPRESSION = transient shaping (adds sustain to tail). reduces dynamic range by making the quiet part BELOW the threshold louder

The free version of Nova (and most compressors in general) feature the first two options, more specialized ones (also) the second two.

The ubiquitos (SP?) OTT features the first and the fourth method in series per band which is pretty unique and actually pretty rare in just one instance of a plugin. In Nova GE you can do this with two bands, one in downward and one with upward compression setup at the same frequencies.

TL;DR version:
- compression reduces dynamic range. Either by making loud stuff above threshold quieter (downward, aka compressor) or quiet stuff below threshold louder (upward, aka upward compressor)
- expansion increases dynamic range either by making loud stuff above threshold louder (upward, aka expander) or quiet stuff below threshold quieter (downward, aka noise gate)

[bmanic]

100% correct and an excellent summary.

[FapFilter]

thank you!

I thought i was going insane trying to actually formulate this without mixing things up myself

[highkoo]

hmm, secret weapon but,
Kiloheartz has a preset in Snapheap called 'OTT' that is supposed to be a cleaner up/down compressor than good ol OTT.
It can push too hard, but its great for that gentle up-only thing for pushing up intricate lil stuff.

[SeBaer]

no problem, it can be confusing…
here's my take trying on explaining as simple as i can:
[...]

Thank you very much. Now that's an explanation I get.

[Grodada]

to complete the list:

ReaComp(free)
waves c1 (and mv2)
neutron izotope

https://www.izotope.com/en/learn/4-tips ... utron.html