Wideband dynamic compression bug, or misunderstanding TDR Nova

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KVRer
8 posts since 28 Feb, 2020

Post Fri Feb 28, 2020 11:43 am

Hi, TDR Nova seems to me fantastic, but I came across something strange, maybe the error is on my side, I have tried many different scenarios, ratios, even with with noise, but here is an example of the issue.
I have generated a test signal, 5 sec intervals of 880 Hz Sine waves from -72dB to -1dB with 1 dB steps. I have compressed this signal with:
Wideband dynamic, 0 dB Gain, -30 dB Threshold, 10:1 ratio, fastest attack&release, no EQ Gain, no Out Gaing, 0% Dry.

What I expected from the math:
-40 dB -> -40 dB
-30 dB -> -30 dB (with a softer knee less)
-20 dB -> -29 dB (with softer knee slightly less)
-10 dB -> -28 dB
-5 dB -> -28,5 dB
-1 dB -> -28,9 dB

What I got:
-40 dB -> -40.04 dB
-30 dB -> -31.20 dB (OK, not hard knee)
-20 dB -> -23,87 dB (huge difference from the expected -29)
-10 dB -> -14,07 dB (seems almost linear from -20 dB)
-5 dB -> -9,07 dB
-4 dB -> -8,07 dB
-3 dB -> -7,07 dB
-2 dB -> -6,07 dB
-1 dB -> -5,07 dB (on the last few 1dB/1dB, not 10db/1db as the ratio would suggest)

So, this not a compressor? What am I missing?

Thanks in advance!

KVRAF
5751 posts since 8 Jun, 2009

Post Fri Feb 28, 2020 12:25 pm

> 880 Hz Sine

> fastest attack&release

I can’t help feeling this combination is the source of the problem.

KVRer

Topic Starter

8 posts since 28 Feb, 2020

Post Fri Feb 28, 2020 12:31 pm

Any attack (eg. slowest/slowest, 50/200 ms) produce the same. (And eg. Dead Duck work as expected.)

KVRian
650 posts since 8 Jan, 2017

Post Fri Feb 28, 2020 3:46 pm

First: No compressor out there is perfect, not evne NOVA, and they all work differently.
Second: Not many people knows this, but NOVA uses RMS compression with a very small RMS window, it will let go very fast peaks.

KVRer

Topic Starter

8 posts since 28 Feb, 2020

Post Sun Mar 01, 2020 8:45 am

I still don't get it: I have tried a -1 dB 40 Hz square wave, with the same 10:1 ratio, and it is -5,07 dB again. In RMS it is from circa +2 dB to circa -2 dB. And with 2:1 ratio is the same. What does the 10:1 ratio even mean?

My best bet is still a misunderstanding on my side, but please help me understand what it is!

KVRer

Topic Starter

8 posts since 28 Feb, 2020

Post Sun Mar 01, 2020 12:28 pm

Maybe it is something like what we can see on the left, a range for the compression, but a surprisingly small range: https://www.junger-audio.com/uploads/im ... ressor.jpg

KVRAF
3405 posts since 27 Dec, 2002 from North East England

Post Sun Mar 01, 2020 12:59 pm

Nova's wideband is unusual in that it can still produce strongly frequency dependent behaviour. Are all bands other than the W-band actually disabled? Parts of the spectrum covered by active bands (even if they don't appear to be doing anything) won't be included in the W-band signal IIRC.

Nova's knee is ratio-dependent incidentally - higher ratio = harder knee.

KVRian
650 posts since 8 Jan, 2017

Post Sun Mar 01, 2020 1:02 pm

cron wrote:
Sun Mar 01, 2020 12:59 pm
Nova's wideband is unusual in that it can still produce strongly frequency dependent behaviour. Are all bands other than the W-band actually disabled? Parts of the spectrum covered by active bands (even if they don't appear to be doing anything) won't be included in the W-band signal IIRC.
This, and the fact that all bands (except the Wideband IIRC) have a 3 db per octave HPF in their side-chain, so they don't go absolutely crazy with low frequencies.

KVRer

Topic Starter

8 posts since 28 Feb, 2020

Post Mon Mar 02, 2020 3:59 am

Yes, I'm aware of the ratio dependent knee.
nova.png
I guess we can even see the -4,07 dB from the yellow line.
You do not have the required permissions to view the files attached to this post.

KVRist
300 posts since 2 Nov, 2020

Post Sat Dec 05, 2020 6:56 am

(double post)
Last edited by ScrLk on Sat Dec 05, 2020 6:58 am, edited 1 time in total.

KVRist
300 posts since 2 Nov, 2020

Post Sat Dec 05, 2020 6:58 am

Have you ever found an answer to this? Maybe you can contact TDR directly...
macmelon wrote:
Fri Feb 28, 2020 11:43 am
Hi, TDR Nova seems to me fantastic, but I came across something strange, maybe the error is on my side, I have tried many different scenarios, ratios, even with with noise, but here is an example of the issue.

KVRer

Topic Starter

8 posts since 28 Feb, 2020

Post Sat Dec 05, 2020 7:40 am

No, yes, maybe if I will have time to do so. In the meantime I have purchased the GE version, will check it too, but not yet. Thank you for your question!

KVRist
300 posts since 2 Nov, 2020

Post Sat Dec 05, 2020 8:15 am

Oh, I remembered something.

Are you aware that Nova has a maximum range of gain reduction?
macmelon wrote:
Sat Dec 05, 2020 7:40 am
No, yes, maybe if I will have time to do so. In the meantime I have purchased the GE version, will check it too, but not yet. Thank you for your question!

KVRer

Topic Starter

8 posts since 28 Feb, 2020

Post Sat Dec 05, 2020 11:54 am

Oh! This must be it.

KVRist
300 posts since 2 Nov, 2020

Post Sat Dec 05, 2020 12:04 pm

In PluginDoctor with Limiter 6 GE's Nova compressor setting, the dynamics graph rises diagonally 1:1... then is compressed by 1:x from the threshold onwards... then reverts back to rising 1:1.

(I don't have a screenshot handy...)

Kotelnikov GE doesn't do this, unless you enable the GR Range parameter.

Whether any of this is desirable... I'm not sure. For cleaning up signals yes, for creative effects like sidechain ducking not so much.

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