Upwards software compressor

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philbagg

philbagg

Just Killing Time
Ok, another question on plugins from me :rolleyes:

Anybody know of any (mac-friendly) upwards software compressors?

I think it'd be very useful for some tracks I have.

Like the piano in this song, it's mostly loud enough to be heard, but there are a few notes that are just too under the bar. Downward compression would make those notes more audible, at the price of making it mostly sound like crap. Upwards compression on the other hand, seems to be a much nicer way of compression :)

Cheers.
 
I'm not sure which DAW software you're using and what it's compliment of native tools contains, but most DAW editors come with a "Dynamics Processor" tool which would allow you to apply exactly the targeted upwards compression you're looking for. Search your native tools menus wherever they have volume/dynamics-type tools organized and/or search the DAWs online help for "Dynamic Processor" or "Dynamics Processing", and you should find what you need.

G.
 
I'm not sure which DAW software you're using and what it's compliment of native tools contains, but most DAW editors come with a "Dynamics Processor" tool which would allow you to apply exactly the targeted upwards compression you're looking for. Search your native tools menus wherever they have volume/dynamics-type tools organized and/or search the DAWs online help for "Dynamic Processor" or "Dynamics Processing", and you should find what you need.

G.

Hey G :)

I'm runnin Pro Tools. I have the dynamics-III stuff, but isn't that compressor just a downward compressor? Or is there something I'm completely missing? :confused:
 
Hey G :)

I'm runnin Pro Tools. I have the dynamics-III stuff, but isn't that compressor just a downward compressor? Or is there something I'm completely missing? :confused:
Re-read my description. I didn't say anything about a compressor ;). The tool is typically referred to as a "dynamics processor". I don't know PT well enough to say if it came with one or not, but I'd be extremely surprised if it didn't automatically come with one right out of the box, because most other editors do.

It may go by a slightly different name in PT, I don't know. But here's a thread that started out asking about something slightly different than what you're asking, but the dynamics processor was the answer there too, and I wound up getting into a pretty detailed description of how the tool works, complete with some screen shots and diagrams and all that fun stuff (if you can make it to page 3 of the thread). That may help you not only find the right tool in PT, but help you finger out how to use it for your needs as well.

G.
 
Anybody know of any (mac-friendly) upwards software compressors?
I think what you are looking for can also be referred to as upwards expansion or possibly parallel compression will work.

The waves C4 and LinPMB will do upwards expansion. For parallel compression you would need a compressor with a wet/dry blend control on it.
 
I think what you are looking for can also be referred to as upwards expansion.
Upwards expansion and upwards compression are not the same thing.

Upwards expansion expands the dynamics of all signals above the threshold up away from the threshold. It is the inverse analog of standard downward compression.

Upwards compression, OTOH, compresses the dynamics of everything below the threshold value up towards the threshold value. It is like the mirror image of downward compression with the threshold being the mirror.

For the OP's situation, he wishes to increase the perceived volume of only the quietest passages of the piano track. Upwards expansion would have to set the threshold below the quiet passages, increasing the dynamic range of the whole piano track. Yes, the quieter parts would increase in volume, but so would the louder parts by the same proportional ratio. This would be undesirable for the OP's described situation.

Upwards compression, OTOH, would work by setting the threshold at a level between the quiet and loud passage levels, and compress the quiet parts upwards toward the threshold level, while leaving the louder parts as they are, thusly "fixing" the quiet problem without unduly altering the louder passages which are OK now.

G.
 
I wrote an article about upwards/ parallel compression and how to do it in Pro Tools and you wont have to buy any waves plug ins or anything. Hope this answers your question.

Parallel Compression in Pro Tools
Problem is, Alan, parallel compression is NOT upwards compression, Parallel compression is the technique of applying a wet/dry mix of downwards compression and uncompressed together, and bears no relation to upwards compression.

G.
 
By using downward compression all signal above the threshold is lowered.

By summing this signal with the original, levels above threshold are not raised as much (since they have been lowered according to the compression ratio) so the net effect is that lower level signals are raised more below threshold.

Not going to get hung up on what this is called, there are already too many names for it.
 
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By using downward compression all signal above the threshold is lowered.

By summing this signal with the original, levels above threshold are not raised as much (since they have been lowered according to the compression ratio) so the overall effect is that lower level signals are raised more below threshold.
If I understand that correctly, that's really just in effect mistaking makeup gain for upward compression. Plus there is still downward compression happening above the threshold.

With true upward compression, there is no effect whatsoever above the threshold. Additionally, because of that, there is usually little or no makeup gain used after the compression has been applied.

G.
 
Not the same as makeup gain G.

With makeup gain one is using downward comp and raising everything up equally. By mixing dry with compressed they are not equal ratios.

Take an extreme case, using a brickwall limiter to knock down peaks 3 dB and then mixing that back in with the original. The signal below threshold will not be affected by the limiting (in theory) so by adding this "limited" signal back at some level it's just raising gain. For signals above thresh it's raising the gain with a signal that is lowered by 3 dB so the overal gain is less.

If one mixed the limited signal with the same limited signal that would be more like makeup gain.
 
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Not the same as makeup gain G.

With makeup gain one is using downward comp and raising everything up equally. By mixing dry with compressed they are not equal ratios.

Take an extreme case, using a brickwall limiter to knock down peaks 3 dB and then mixing that back in with the original. The signal below threshold will not be affected by the limiting (in theory) so by adding this "limited" signal back at some level it's just raising gain. For signals above thresh it's raising the gain with a signal that is lowered by 3 dB so the overal gain is less.

If one mixed the limited signal with the same limited signal that would be more like makeup gain.
Ok, Tom, I get how I was wrong about the makeup gain thing, I misinterpreted where you were going with that. I'm Ok with that now (I think? ;) :))

But help me out, I'm thinking out loud here...

Let's say one sets a threshold that just so happens to be somewhere around the RMS level of the signal (I know, the RMS level is dynamic, but bear with me, that's just a reference point for now). With any wet/dry combo of downward compression, the crest factor is going to shorten, right? Put another way, the nature of the dynamics above the initial threshold is going to change, isn't it? And at the same time the dynamics of the signal below the threshold are going to (in a theoretical perfect world) are going to remain intact, even if the wet/dry summing does increase the gain by a few dB more than it does above the threshold.

With actual upward compression - a la dynamics processor or something like RND's Dynamizer - the dynamics below the threshold are compressed up towards the threshold instead of remaining intact, and the nature of the peak dynamics are going to remain untouched. In this way, upwards compression is still in many metrics the opposite of even parallel compression.

And to take it back to the OP's problem, where he doesn't want to mess with the louder parts of the piano at all, but just wants to bolster the weaker amplitude notes, wouldn't upwards compression fit the bill much tighter than parallel compression would?

Or am I missing something obvious here (yet again)?

G.
 
With actual upward compression - a la dynamics processor or something like RND's Dynamizer - the dynamics below the threshold are compressed up towards the threshold instead of remaining intact, and the nature of the peak dynamics are going to remain untouched. In this way, upwards compression is still in many metrics the opposite of even parallel compression.

And to take it back to the OP's problem, where he doesn't want to mess with the louder parts of the piano at all, but just wants to bolster the weaker amplitude notes, wouldn't upwards compression fit the bill much tighter than parallel compression would?.

I think some of it comes down to semantics, but in theory, with parallel compression you are leaving the high peak information alone (for the most part where it was originally at) but you raising up the lower peak information relative to it, so this does increase the weaker notes relative to the louder ones...and to me it's seems very similar to what you are describing with upwards compression. Seems like you would get the same end result.
 
With actual upward compression - a la dynamics processor or something like RND's Dynamizer - the dynamics below the threshold are compressed up towards the threshold instead of remaining intact

Now I'm getting confused.

Glen, can you find me a more complete description of this process? Compressed up seems like an oxymoron. If you are reducing the dynamic range below threshold that would be downward expansion. It seems like what your saying is that there is some sort of downward expansion and this component is fed back in without the component of the signal above the threshold?
 
This is quoted from Robin S (24-96)

Basic types of compression:

Downward compression: attenuating the signal at a ratio when it rises over a set threshold. (Turning the loud parts down, diminishing dynamic range) [Waves R-Comp with Ratio in ORANGE range]

Upward compression: effectively boosting the signal at a ratio when it drops below threshold (Turning the quiet parts up, diminishing dynamic range) [Procedures vary]

Downward expansion: attenuating the signal at a ratio when it drops below a set threshold (Turning the quiet parts further down, increasing dynamic range - think of a noise gate that doesn't completely cut the signal below threshold, but turns it down gradually.) [Expander on a Yamaha digital desk, for example]

Upwards expansion: boosting the signal at a ratio when it rises over a set threshold. (Turning the loud parts further up, increasing dynamic range) [Waves R-Comp with ratio in the BLUE range]

Parallel compression: is a way of achieving upward compression by mixing an uncompressed signal with a (downward) or an un-compressed signal.
 
Good summary Tom.

This could be an interesting experiment, not sure what it would be called.

1. Take a signal and use downward expansion so that audio below threshold was brought down.

2. Reversed the polarity of the signal from step 1 and feed this back to the original signal cancelling out the audio that was not processed below the threshold, this would leave you with the reduced part of signal from downward expansion.

3. Mix this back into the original source track in parallel.

It seems like this would bring up the transients in the audio below threshold without affecting anything above.
 
I think some of it comes down to semantics, but in theory, with parallel compression you are leaving the high peak information alone (for the most part where it was originally at) but you raising up the lower peak information relative to it, so this does increase the weaker notes relative to the louder ones...and to me it's seems very similar to what you are describing with upwards compression. Seems like you would get the same end result.
Yeah, with parallel compression you are raising the weaker notes relative to the higher stuff, but it's not actually quite the same thing, and the end result would indeed be be a bit different than pure upward compression.

With the parallel compression, you may be raising the weaker notes compared to the higher ones, but you won't be changing the relationship of the quieter notes to each other. Let's say for sake of illustration that you have two notes below the threshold, one is 3dB down and the other is 6dB down from the thresh. When you apply parallel compression, those numbers will not change. While the dynamic range between them and the main energy of the upper peaks. will shorten, they will still be riding the same distance from each other and still be riding well below the RMS by the same varying degrees.

With upwards compression, however, the sub-threshold dynamics will be compressed upwards towards the threshold point, having the dual effect of both leveling out the volume of the weaker notes and pulling them up louder in relation to the signal RMS (assuming the RMS is above the weak notes). With the numbers given, if we apply an upwards compression of, say, 3:1 for example, with the threshold set somewhere around the RMS level, the two weak notes will now be 1dB and 2dB down from the threshold/RMS, much louder in relation to the average perceived level of the overall waveform and only one dB apart in volume between them, instead of 3dB. Plus there will have been zero change made to the stuff above the threshold, compared to a summing of wet and dry versions of it.
Now I'm getting confused.

Glen, can you find me a more complete description of this process? Compressed up seems like an oxymoron. If you are reducing the dynamic range below threshold that would be downward expansion. It seems like what your saying is that there is some sort of downward expansion and this component is fed back in without the component of the signal above the threshold?
Tom W described it pretty well, but here's a couple of pretty pictures that may help as well. The first is a kind of a schematic difference between upward and downward compression and upward and downward expansion. They are four different things:

compression_expansion.jpg


And maybe this next one might help to show the difference between downwards and upward compression in another way. This is part of a display from Elemental Audio's Neodynium (a.k.a. Roger Nichol's Dynamizer). It shows two dynamic range zones set up, both with a threshold of -10dBFS. The top (red) zone I have set up from 0dBFS to -10dBFS, and has meen configured with a downward compression of 3:1 applied to it, which is graphically represented by the narrowing down to the right, The lower (orange) zone, I set up from -10 to -20dBFS also has 3:1 compression applied to it, but it is an upward compression instead of a downward one, represented by the narrowing of the zone upwards on the right.

compression_up_down.jpg


For the OPs situation, I would use Neodynum (my favorite compression plug, BTW; it has a LOT more than just what you see here) set up with one dynamics zone set up similar to the orange zone in order to upward compress the weak notes, evening out their volume somewhat while leaving the peak stuff completely alone. The threshold would depend upon the actual recording, and the low end of the zone would be just low enough to cover the notes I'd need to bolster.

G.
 
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I'm sorry Glen but the term "compress upwards" as you have posted is still ambiguous to me.

Tom's definition of upward compression is the same as the one used in chapter 11 of Bob Katz' book which explains the process of upward compression per Richard Hulse (parallel compression).

With an expander or compressor you are either increasing the dynamic range or decreasing it. This can be done either above or below the threshold.

Are you defining an upward compressor as a compressor which lowers levels below threshold and then applies makeup gain only to the signal below threshold?
 
Are you defining an upward compressor as a compressor which lowers levels below threshold and then applies makeup gain only to the signal below threshold?

No. If a signal is below a threshold, it make it louder up to that threshold.

So if you ran a brutally high ratio with an instant attack and release and a threshold of -20, everything below -20 would be shoved up against a ceiling at -20, and everything above -20 would be natural.
 
Mastering, you're thinking about the word compression wrong. It doesn't necessarily mean gain reduction. It just means dynamic range reduction. IE, the difference between an upward and downward compressor is that the downward compressor decreases dynamic range by reducing gain above a threshold, and the upward compressor reduces dynamic range by increasing gain below the threshold. In both cases, the signal on the other side of the threshold (below it for downwards compression and above it for upwards compression), ignoring the effects of a soft knee, is unaffected.
This is where the critical difference between upward compression and parallel compression lies. Parallel compression does increase gain below the threshold, but it does it at the cost of altering the signals above the threshold. It combines the original signal's above-the-threshold peaks with the compressed peaks from the compressed signal.
G (and the OP, for that matter) is right in that, if the OP wants to completely leave the dynamics and tonality of the above the threshold peaks alone and only alter the signal below the threshold, an upward compressor is what's called for.
 
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