Cytomic 'The Glue' Compressor

[egbert]

Read Andy's post with more attention. The low pass filter is applied to the sidechain only, not to the actual sound going thru.

What explains the rolloff at the top end of the frequency plot obtained after the 993Hz sin signal was processed (ie program material) by The Glue?

[michu]

as Andy mentioned - a lowpass filter at 15 kHz would explain that. placed in a sidechain. not affecting program material directly. affecting only the way compression artefacts are created. compression artefacts are everything in the plot except the 993 Hz sine wave peak.
also please note, that .1 mS attack time was used and that is main reason for harmonic artefacts, and they are present mostly during attack stage of an envelope. also also please please note, that average level of artefacts starts at around -70 dB and roll-off somewhere around -96 dB.

[meloco_go]

Read Andy's post with more attention. The low pass filter is applied to the sidechain only, not to the actual sound going thru.

What explains the rolloff at the top end of the frequency plot obtained after the 993Hz sin signal was processed (ie program material) by The Glue?

It is smother gain-reduction action.

[egbert]

as Andy mentioned - a lowpass filter at 15 kHz would explain that. placed in a sidechain. not affecting program material directly. affecting only the way compression artefacts are created. compression artefacts are everything in the plot except the 993 Hz sine wave peak.

Program material is the input - the plot with all the harmonic peaks at multiples or 993 Hz is the plot of the compressor output - n'est pas?

If you round off the top of the sin wave like this you are effectively soft clipping it and adding a whole spectrum of higher partials to the processed signal - this happens in the analog domain too of course.

When you make fast changes to the amplitude of the imput signal (eg VCA acting on a high amplitude transient - even if it is a sin wave) you introduce harmonic distortion. Applying radidly changing gain reduction, you change the shape of the signal being processed to a new shape - you literally distort it. This results in the colouration which is part an parcel of fast acting compression - eg applied with a fast attack (eg 4:1 compression with a 1 msec attack applied to a bass guitar note or a kick drum).

Adding this colouration is a necessary consequence of the job a compressor is required to do in these sorts of cases. It is not a fault with the design. The red aliasing in those graphs is the result of imperfections in the digital processing. The fact that there is so little in the plot for The Glue indicates that it is doing a good job.

[andy-cytomic]

So the quotation was correct? Those were in fact andy's words under the graphs - that's the way I took it originally and several people jumped on me.

The words under the graphs were not from me, the person that said them was izonin.

In case anyone doesn't know what a one pole low pass filter at 15kHz entails - that frequency is the -3dB point and the slope is -6 dB per octave. If that filter is being applied to all wet output there will be a noticeable reduction in the high end - which is not necessarily a bad thing.

You need to read my post a little more carefully. The filter is being applied to the envelope follower signal which adjusts the gain, it is not in the main audio path.

[egbert]

Thanks for the clarification andy, michu and meloco_go. Carry on.

[Spitfire31]

… the plot with all the harmonic peaks at multiples or 993 Hz is the plot of the compressor output - n'est pas?[sic!]

If you aim to flaunt your language skills, the effect would be greater if you did it correctly, n'est-ce pas?

Kind regards,

Joachim

[egbert]

If you aim to flaunt your language skills, the effect would be greater if you did it correctly, n'est-ce pas?

Touche!

And you managed to say this with what looks (correct me if I've got this arse-about - it's been a while since I studied French) like a reasonably horrendous mangling of the tenses.

You have invoked the conditional mood. It seems to me you have the equivalent of "is it not?" there but to agree with the future conditional thing you have going [if you aim ... the effect would be greater ...] you would want the french equivalent of "would it not?" would you not?

[egbert]

BTW - I forgot to say, you also screwed up the English. In that structure you would need to have said: "would be greater if you had done it...".

So, you violated two languages in one sentence. I salute you.

Kind regards,
egbert

[Spitfire31]

I seem to have lit a linguistic fuse. I had no idea that you'd be so personally affected, egbert, and I apologise most profusely for upsetting your emotional balance.

Peace?

Kind regards,

Joachim

[billcarroll]

Can you smell that? I just I love the smell of KVR threads (napalm) in the morning.

I could swear this thread was about a compressor at some point ....

[egbert]

I seem to have lit a linguistic fuse. I had no idea that you'd be so personally affected, egbert, and I apologise most profusely for upsetting your emotional balance.

Peace?

Kind regards,

Joachim

Not at all. This just amused the hell out of me.

This sort of thing is often cited as almost being a "law of the internet": If you go out of your way to chide someone for a typo, mis-spelling or grammatical error, your post will almost invariably include an error of your own. Others will then jump on you mercilessly and rub your face in it - and you really can't expect them to say "there but for the grace of God go I" because of your own aggression/pedantry. I see this often in forums here in Australia.

The upshot of all this - which is deemed a variation on Murphy's Law, is that it is better to avoid indulging in such things lest you be hoisted on your own petard.

Anyway, I thought you could have been a bit sporting and replied in good humour. No need for supplication - ironic or otherwise.

[egbert]

Can you smell that? I just I love the smell of KVR threads (napalm) in the morning.

I could swear this thread was about a compressor at some point ....

Now you're talking. After 181 pages, this thread was crying out for some comic relief.

[hibidy]

Can you smell that? I just I love the smell of KVR threads (napalm) in the morning.

I could swear this thread was about a compressor at some point ....

I have one legitimate question concerning the product, ignored

[AudioGuy720]

Some of the best mix and mastering engineers in the world can't put together sentences and would be dead in the water without spell check. I'd rather be those guys and have the grammar police after me than be in my current position.

Just sayin'...