No, they don't. They do something like:

Code:

y = output_envelope
g = gain
x = envelope
d = threshold
r = ratio


y += g(x)

g(x) =  (
            x >= d ? ( x )
            x <  d ? (
                 d ^ ( 1-(1/r) )
               - x ^ ( 1/r )
            )
        )

 

Last edited: Nov 11, 2022

Apparently not quiet but with make up gain it does?
Is this graphic true or bs?

 

I am not disagreeing with anyone about this topic because I almost never use this processor OTT for what I do. I think a misconception some people have is that an Upwards Compressor is actually like a Clipper, but flipped upside down. Their desired outcome is to have it "lift" the stuff most people would just Low Cut, and they think this will add density.

I am not saying this is correct either. But I have watched a number of "Respectable" videos, (non-YT things); where a producer puts OTT on a track and they can't explain what this plugin even does inside it. Some people do not have a very clear understanding of it. Like all other compressors.

 

It's kinda true, because first you lowered the peaks, but if you gain afterwards to the same amount, it's like you raised the lows.
But I do not see a specific reason to do this anyways.

 

It's accurate according to my 25+ years of experience. But I don't have the f"#%¤ing equation to backing it up.
Edit: I stand corrected.
"'upward compression' and 'uplift compression' do not achieve the same result, even if they do achieve a similar degree of dynamic-range reduction."
I think the "dynamic range reduction" is what is key and why I like it so much.

 

Last edited: Nov 11, 2022

It is BS because Upward Compression does not include Downward Compression as shown in the picture.
Downward Compression and Makeup Gain is not Upward Compression, but Downward Compression with Makeup Gain.

Downward Compression = If envelope is above threshold, multiply the difference between envelope and threshold by ratio. Subtract result from output.
If envelope is below threshold, do nothing.

Upward Compression = If envelope is below threshold, multiply the difference between envelope and threshold by ratio. Add result to output.
If envelope is above threshold, do nothing.

Parallel compression = If envelope is above threshold, multiply difference between envelope and threshold by ratio. Subtract result from output. Add output envelope to input duplicate.

All three methods lead to different results.

 

Last edited: Nov 11, 2022

Up to 0:16

 

Once I found two better pics

Spoiler: compression - expansion 1

Spoiler: compression - expansion 2

 

And that is not wrong.
The difference between a clipper and a compressor lies in the time constants for the transfer.
While the time constants of a clipper (or waveshaper in general) are 0, it reduces the level of each sample that exceeds the threshold by the set ratio.
A compressor, on the other hand, takes time to reduce the level by the set ratio after the threshold is exceeded. This is because attack and release here determine how quickly (~70% of) the set ratio is reached during gain reduction.
For this reason, a compressor distorts the signal if attack and release are set too short. You are already waveshaping.

No, I don't get that.

 

Laughed my fucking ass off

 

Red Phatt Pro Red Phatt Pro provides flexible and powerful dynamics processing.

 

I used to put Waves MV2 on my preview channel to boost even really low level stuff loud enough to try in a mix.
I used the downward aspect as more of a limiter.
I like Thomas Mundt Loudmax for that use lately.
Those can both act as upwards compressors, right?
That is what i THOUGHT i was doing..

 

But no upward.
EDIT: added strike through.

 

Last edited: Nov 11, 2022

Well its in the presets!

 

I wouldn't put much stock in the names, but you seem to be right, sorry. The left part of the reduction curve in the graph even looks like it's upward compression. My fault.

 

That's why I said it needs to have a range parameter. If the downwards compressor (that you are using to create upwards compression with) doesn't have a range parameter, it will continue compressing after it has hit what should be the comparable upwards threshold.

Here's a pic to show what I mean. The purple line is what Pro-C2 looks like with both range and makeup set to +18dB, and the pink is what it looks like with range set maximum (so regular downwards compression/limiting, just with makeup gain). I lowered the output with 1dB for the latter example just so that the two lines don't cover each other.


And here's a comparison with Pro-MB set to upwards compression and a ratio of 3:1 (output at -1dB).


The algorithms themselves can be different for upwards compressors, but you can create the same effect with many regular compressors. If you have a downwards compressor that can do negative ratios, the difference becomes even less.

 

Thank you for the measurements.
I would shoot in the dark and say that the hearing result will probably not be the same, but should at least be similar.
A null test between pro-mb and pro-c2 should clarify the differences. My guess is that there will be a significant difference in the attack and release phase. But I could be wrong, of course. It wouldn't be the first time.

A downward compressor with negative ratio is an expander. If it has a range parameter, you can use it for upward compression, yes, you are absolutely right.

 

Last edited: Nov 11, 2022

Not quite. A downwards compressor with a negative ratio will cause an "overshoot" (don't know if it has a technical term), it will basically start to decrease the level below the threshold when it hits the threshold. That's exactly what a high ratio upwards compressor does as well!

Klanghelm DC8C3 with a negative ratio of -4:1.


Pro-MB in pink (upwards compression, ratio of 5:1) and Klanghelm DC8C3 in purple (negative ratio of -1:1, with range and makeup set to to act as an upwards comp).


I don't think you can get a compressor to act as an expander in any way, actually You can get a donwards compressor to act as an upwards compressor (and vice versa), and you can get a downwards expander to act as an upwards expander (and vice versa), but you can't get a compressor to act as an expander. I might be wrong though!

 

Ok, maybe you are right. I'll read your post and my last post again tomorrow. I don't want to muddy the waters. Right now, thanks to the whiskey, I'm definitely not able to think analytically anymore.

 

What about ratios less than 1:1 like 0.5:1? This should result in an upward expansion.