I obtained a used Ashly CLX-52 compressor from ebay. I ran a quick test playing some music through it, my signal chain is Audio Interface (Focusrite Scarlett 2i2) ==> Compressor (Ashly CLX-52) ==> Monitors (KRK Rokit 5) all with balanced TRS cables.
Everything seems to be working fine apart from the fact that the compressor is causing an audible crackling noise whenever it is compressing. This noise disappears when I disengage the 'In' button to bypass the compressor. Keep in mind that it is not a true bypass as the input and output gain controls remain unaffected.
This crackling noise seems to happen on either channel even with slow attack/release times and light ratios and threshold settings.
Is this normal?
Should my compressor be making a crackling noise?
Re: Should my compressor be making a crackling noise?
It doesn't sound normal. Can you adjust the threshold so that no compression occurs and does it still happen then?
Have you monitored the input signal level to make sure that it's not too hot and possible causing the compressor to distort (though with a quoted maximum input level of +23dBu it shouldn't ever be with the Focusrite output)?
Have you monitored the input signal level to make sure that it's not too hot and possible causing the compressor to distort (though with a quoted maximum input level of +23dBu it shouldn't ever be with the Focusrite output)?
Reliably fallible.
Re: Should my compressor be making a crackling noise?
Of course it's not normal!
It is not unusual to get a 'crackling' effect (actually transient distortion) if the attack time is stupidly fast with some types of audio material, and I would have suggested that you try with a slower attack time in case that was the problem here... but as you've already tried that we can rule that out.
The other obvious possibilities are overload/clipping of the device itself, or -- more likely -- the speakers it is connected to. So try turning the input and output controls down and see if that helps. Wonk's suggestion to raise the threshold to stop any gain reduction is also a worthwhile test.
Other than that, I would guess there is something awry in the gain-reduction circuitry. I'm not familiar with the unit, but I'm guessing its a VCA type, in which case the VCA section might need recalibration which would involve an experienced technician, a lot of measurement gear, and the service manual....
H
It is not unusual to get a 'crackling' effect (actually transient distortion) if the attack time is stupidly fast with some types of audio material, and I would have suggested that you try with a slower attack time in case that was the problem here... but as you've already tried that we can rule that out.
The other obvious possibilities are overload/clipping of the device itself, or -- more likely -- the speakers it is connected to. So try turning the input and output controls down and see if that helps. Wonk's suggestion to raise the threshold to stop any gain reduction is also a worthwhile test.
Other than that, I would guess there is something awry in the gain-reduction circuitry. I'm not familiar with the unit, but I'm guessing its a VCA type, in which case the VCA section might need recalibration which would involve an experienced technician, a lot of measurement gear, and the service manual....
H
Last edited by Hugh Robjohns on Tue Oct 02, 2018 12:51 pm, edited 3 times in total.
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- Hugh Robjohns
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(But generally posting my own personal views and not necessarily those of SOS, the company or the magazine!)
In my world, things get less strange when I read the manual...
(But generally posting my own personal views and not necessarily those of SOS, the company or the magazine!)
In my world, things get less strange when I read the manual...
Re: Should my compressor be making a crackling noise?
Wonks wrote:It doesn't sound normal. Can you adjust the threshold so that no compression occurs and does it still happen then?
Have you monitored the input signal level to make sure that it's not too hot and possible causing the compressor to distort (though with a quoted maximum input level of +23dBu it shouldn't ever be with the Focusrite output)?
I turned the threshold up to allow for no compression and the crackling does disappear. I also tried leaving the threshold where it was and turned down the input and output gains to check for overload/clipping but this didn't work, the noise it still present.
Re: Should my compressor be making a crackling noise?
Sounds like a VCA calibration/fault issue to me.
H
H
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- Hugh Robjohns
Moderator -
Posts: 43691 Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Contact:
Technical Editor, Sound On Sound...
(But generally posting my own personal views and not necessarily those of SOS, the company or the magazine!)
In my world, things get less strange when I read the manual...
(But generally posting my own personal views and not necessarily those of SOS, the company or the magazine!)
In my world, things get less strange when I read the manual...