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SSL SiX Channel Compressor Distortion
Old 6 days ago
  #1
Gear Head
 

SSL SiX Channel Compressor Distortion

Since I discovered its existence the SiX is the heart of my little setup and I just love it! But as already mentioned in the ultimate plugin analysis thread I stumbled upon some unusual distortion when I engage the channel compressor. I passed simple sine waves at different frequencies through the line input, the result can be seen in the screenshots attached. When I disengage the channel compressor the distortion disappears almost completely. I also tried the GBus comp for reference - no unusual amount of distortion. I also measured my KT 76, even patched into the channel insert - no unusual amount of distortion.

Since 50Hz appears in the bottom part of the distortion, which is our AC frequency here in Germany, it seems to be somehow ground related. But why does it only show up when I engage the channel compression? I know there is auto gain compensation going on, but even with the compression knob completely counter clockwise there is a tremendous amount of distortion (see screenshots).

Please tell me I am an uneducated hobby noob and I am doing something wrong, because that is what I am hoping for.

Edit: I forgot to mention that it’s the same with channel both channels.
Attached Thumbnails
SSL SiX Channel Compressor Distortion-ssl_six_nocomp.jpg   SSL SiX Channel Compressor Distortion-ssl_six_channelcomp.jpg   SSL SiX Channel Compressor Distortion-ssl_six_channelcomp_100hz.jpg   SSL SiX Channel Compressor Distortion-ssl_six_gbuscomp_100hz.jpg   SSL SiX Channel Compressor Distortion-ssl_six_nocomp_777hz.jpg  

SSL SiX Channel Compressor Distortion-ssl_six_chcompccw_777hz.jpg   SSL SiX Channel Compressor Distortion-ssl_six_chcompcw_777hz.jpg  

Last edited by Its Mork; 6 days ago at 09:35 PM.. Reason: See edit
Old 6 days ago
  #2
I do see what you are trying to say, but i have one question. Do you hear it?
Old 6 days ago
  #3
Gear Head
 

Hehe, I know what you are getting at and believe me, I used to be the analyzer guy, reading about standards and majoring the minors. Sure you should do your homework but it’s like in this thread I mentioned: It shows that basically all top plugins introduce non harmonic distortion and are therefore „unusable“ - the same plugins that you can hear in probably most of your and my favorite mixes...
To finally answer your question: Maybe. There is always a level bump when the circuit is engaged so it’s hard to compare. Plus I usually used it after the KT76 which already introduced distortion. It‘s at least not a bad as it looks, although the compressor is already known to „fart“ with bass heavy content. This may have something to do with this, maybe not. Now I will first have to „unhear“ it.

Let me add that I just want to know what’s going on. I’m fine with „Yup, that’s what it‘s like“ as much as with „You‘re an idiot and hooked it up all wrong“ or „Please send in your unit“.
Old 6 days ago
  #4
Quote:
Plus I usually used it after the KT76 which already introduced distortion
If its audible and interfering with your sound, i would take this out, since you have proven that its making the distortion in the signal chain
Old 6 days ago
  #5
Gear Head
 

Sorry, do you mean the 76kt? It’s an 1176 clone which is supposed to distort. It’s not in the chain I measured, of course. I measured DAW out —> Input channel —> Main out —> DAW in.
Old 6 days ago
  #6
Quote:
Sorry, do you mean the 76kt?
I quoted you.
Quote:
usually used it after the KT76 which already introduced distortion. It‘s at least not a bad as it looks, although the compressor is already known to „fart“ with bass heavy content. This may have something to do with this,
You said you use 76kt in your chain
Old 6 days ago
  #7
Gear Head
 

That was meant to explain why I am not quite sure that I‘ve heard the SiX compressor distort (while mixing), because I usually put an already distorted signal signal through it, like a vocal. That makes it more difficult to spot the added distortion. The measurements were taken without any added sources of distortion of course. Sorry, I should have been more clear about that
Old 3 days ago
  #8
Here for the gear
 

Yes, I can confirm that the SSL SiX channel compressor distorts on bass-heavy signals. It's not even subtle.

I was hoping that I would be able to track bass guitar using the SiX SA channel, with the comp smoothing out the performance. Unfortunately, the results are unusable.

The sound is as if the attack and release are set in such a manner that it is repeatedly opening and closing down based upon the input waveform.

The comp sounds fine on vocals. Sucks on bass guitar. I'm new to the unit, so have not really tried pushing it with any other sources.
Old 3 days ago
  #9
Gear Head
 
Bollinja's Avatar
Quote:
Originally Posted by jbreher View Post
The comp sounds fine on vocals. Sucks on bass guitar.
Someone mentioned something similar on another forum.
Old 3 days ago
  #10
Here for the gear
 

How is the buss comp on the bass frequencies?
Old 3 days ago
  #11
Here for the gear
 

Here is the forum, or a forum that mentions this.

https://www.soundonsound.com/forum/v...65524&start=60


It seems that the channel comps are for vocals etc and not designed for bass.
It is not a design fault but has fixed parameters-only the threshold is adjustable.
Old 3 days ago
  #12
Lives for gear
 
DirkP's Avatar
Quote:
Originally Posted by BEEHIVE View Post
Here is the forum, or a forum that mentions this.

https://www.soundonsound.com/forum/v...65524&start=60


It seems that the channel comps are for vocals etc and not designed for bass.
It is not a design fault but has fixed parameters-only the threshold is adjustable.
But I still think it is an engineering fault. I am a bassplayer and I have owned and tried a lot of different compressors and limiters, among them many cheap ones and some not at all designed for bass. None of them showed this kind of behaviour. The channel comp of the Six - otherwise a great great piece of gear - goes into a kind of self-resonance (but not the moog or 303 kind of self resonance) as soon as it is confronted with ordinary bass frequencies. For example: a simple Fender Precision plugged in.

What I don't like about it at all: this can totally ruin otherwise brilliant recording takes.
It's not that it sounds not good with bass. I could live with that. It's that self-resonating rattling distortion.

A decent piece of audio-gear like a mixer should handle signals from 20 to 20.000 hz without creating such mess. The SiX is ten times the money of mixers with channel compressors that don't ruin the entire audio-chain when confronted with bass material.
I can live with it and don't use the channel-compressor for bass. But for the reputation of a company like SSL this is embarassing. Did they never try it with ordinary audio material fed to the channels before selling it???

https://www.dropbox.com/s/d59jl8ufg8...0comp.mov?dl=0
Old 3 days ago
  #13
Gear Head
 

Quote:
Originally Posted by BEEHIVE View Post
How is the buss comp on the bass frequencies?
I didn’t do a separate 100 Hz measurement for the buss comp, because it is nothing like the channel comp and handles bass heavy material very well. By now I used it enough (far more than the channel comps) to confirm that it absolutely rocks!
I would add a screenshot unfortunately I am on the road at the moment. If I don‘t forget I will add it when I am back home and have the time to do so.
Old 3 days ago
  #14
Here for the gear
 

Quote:
Originally Posted by DirkP View Post
But I still think it is an engineering fault. I am a bassplayer and I have owned and tried a lot of different compressors and limiters, among them many cheap ones and some not at all designed for bass. None of them showed this kind of behaviour. The channel comp of the Six - otherwise a great great piece of gear - goes into a kind of self-resonance (but not the moog or 303 kind of self resonance) as soon as it is confronted with ordinary bass frequencies. For example: a simple Fender Precision plugged in.

What I don't like about it at all: this can totally ruin otherwise brilliant recording takes.
It's not that it sounds not good with bass. I could live with that. It's that self-resonating rattling distortion.

A decent piece of audio-gear like a mixer should handle signals from 20 to 20.000 hz without creating such mess. The SiX is ten times the money of mixers with channel compressors that don't ruin the entire audio-chain when confronted with bass material.
I can live with it and don't use the channel-compressor for bass. But for the reputation of a company like SSL this is embarassing. Did they never try it with ordinary audio material fed to the channels before selling it???

https://www.dropbox.com/s/d59jl8ufg8...0comp.mov?dl=0



Agree.

A compressor is for audio signals generally i would have thought , whatever the range of frequency. Seems odd that it should differentiate which signals it would work with and not others have to say. Also odd that users have had to find this out for themselves OR is it a feature that is described in the manual- that the channel comps only work with such and such audio signals?
Old 3 days ago
  #15
Here for the gear
 

'I didn’t do a separate 100 Hz measurement for the buss comp, because it is nothing like the channel comp and handles bass heavy material very well. By now I used it enough (far more than the channel comps) to confirm that it absolutely rocks!'

Thats great.
Old 2 days ago
  #16
Lives for gear
 
DirkP's Avatar
Quote:
Originally Posted by BEEHIVE View Post
'I didn’t do a separate 100 Hz measurement for the buss comp, because it is nothing like the channel comp and handles bass heavy material very well. By now I used it enough (far more than the channel comps) to confirm that it absolutely rocks!'

Thats great.
afaik the buss compressor has a high pass filter and simply ignores bass. makes not much sense to use it for bass or just as an effect that leaves the low frequencies untouched. for a bus comp this makes sense to prevent the bass from ruling the entire compression, for bass compression not so much.
Old 2 days ago
  #17
Gear Head
 

The buss comp has a high pass at 50Hz in the sidechain, the compression is wideband. You could absolutely use it on bass guitar, never tried it though. I guess it could be cool if you’re going for a punchy sound. Now I HAVE to try it
Old 2 days ago
  #18
Here for the gear
 

Wonder if SSL will adjust the channel comp to be able to work with all signals?
Old 1 day ago
  #19
Gear Head
 

I got an answer from SSL. Part of the distortion is normal part of it is not. It would be great if someone else could measure the channel comp to have a comparison.
Old 1 day ago
  #20
Here for the gear
 

Quote:
Originally Posted by Its Mork View Post
I got an answer from SSL. Part of the distortion is normal part of it is not. It would be great if someone else could measure the channel comp to have a comparison.

Oh? Wonder what that means?


Going to get one anyway. Initally it put me off, not sure why.
Old 1 day ago
  #21
Gear Nut
 

Quote:
Originally Posted by Its Mork View Post
I got an answer from SSL. Part of the distortion is normal part of it is not. It would be great if someone else could measure the channel comp to have a comparison.
So are they offering to replace / service yours? If the distortion is "not normal" then I imagine they're saying yours is faulty, no?
Old 1 day ago
  #22
Gear Head
 

Yes they do. But I would prefer to see some comparisons before going through the hassle of swapping it out.
Old 1 day ago
  #23
Lives for gear
 
DirkP's Avatar
Quote:
Originally Posted by Its Mork View Post
Yes they do. But I would prefer to see some comparisons before going through the hassle of swapping it out.
Did you listen to the example I've sent?
Old 1 day ago
  #24
Gear Head
 

Yes I did, but unfortunately this is „normal“. I also noticed this with subby Bassdrums and I really hope they fix the compressor design. Swapping out the desk will not make any difference in this regard which is why I am interested in measurements by someone else, to see if the amount of distortion is the same especially in the midrange.
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