Crackling and distortion when recording through Focusrite
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I installed EQ-APO to use on live speech input for podcasting and conference chairing. Focusrite Scarlett 2i2 works OK with an AT2020 microphone. After installing EQ-apo, the sound is not affected by distortion and crackle - so long as I do not adjust the Graphic EQ by the slightest amount. As soon as any adjustment to the Graphic EQ settings in EQ-APO is made, there is distortion and crackle on the input (recorded in Audacity). Focusrite is set to a sample rate of 44100 with a buffer of 128 and I have the Realtek-HD driver in a Dell XPS laptop.
I attach an example of the recorded distortion and crackle.
I am anew to this so don't assume I have checked the basics.
Hoping for help...
Bill
IIRC, it's known issue for GraphicEQ (actually, why to use it at all) but, problem could also be partly related to short buffer used in Focusrite settings. Remember that you use WASAPI Shared mode which is not good with low latency operations. You can check if this is the root for your problem by setting Focusrite buffer to 2048 samples.
Thanks, Juha, I'll check those out later and get pack with the outcome here.
Just use biquad filters. For preventing this distortion issue of GraphicEQ the Peace equalizer uses peak filters (and others) for EQ-ing (although GraphicEQ is still present under a button). And biquad filters are faster too :)
I have discovered that it is the 44100 sample rate that is causing big distortion when EQ not completely flat!! 48000 and above are OK. However, I now notice that adjustments to EQ levels in EQ-APO don't have any effect (except, of course, to cause distortion at the lowest sample rate).
Juha,
I changed mode had no effect. It is on the input and appears on all recordings, not just Audacity. Neither did increasing the buffer. Thanks for these ideas
Peter,
Thanks for suggestion but I do not know what a biquad filter is. Is it is something I can change in EQ-APO or is a fundamentally different tool? I am about to research it. Sorry for my ignorance
You can insert biquad filters through Configuration Editor. Here are list of commands supported by EqualizerAPO . You can also use Windows own Notepad editor (or any other pure ASCII editor) to open/modify/save the configuration file config.txt (config.txt can be found under EqualizerAPO installation folder.
Last edit: Juha 2023-02-22
No problem. In the Configuration Editor the EQ is being done with GraphicEQ hence the issue you're experiencing. When you look at the Peace equalizer you see, well, an equalizer matching a hardware equalizer (if you're familiar with that). So Peace uses peak filters which are more or less the same as using GraphicEQ. But with the Configuration Editor using biquad filters like peak filters is difficult for a beginner.
When you say it has any effect, that is part of the issue. So hearing distortion, no eq-in is being done.
Hi Guys
Now I get the same distortion at 48000 sample rate, as well as 44100; but OK at 88000.
Equaliser controls still appear to have no effect
Thanks, Peter, Juha
I am sorry to say that I may have wasted your time. The same problem has now appeared in Audacity after EQ-APO had been uninstalled. The recording was OK but an attempt to EQ it created the same distortion which did not disappear completely when I undid the EQ change.
I really do appreciate your help and I enjoyed following up your advice and learning from it. If you have any further ideas what is causing this I'd be grateful - even though it has nothing to do with EQ-APO.
No problem, Bill.
Audacity does EQ in the same way. Although a bit unlikely it might be the same issue!
Quick follow up. I found a second, hidden version of Realtek HD, so removed both and and re-installed one.
That improved a few things but not the distortion after adjusting EQ levels.
However, it does all I want it to, without distortion and crackling, using its standard high-pass filter set a 120 and a Q-factor of 0.7.
Nice catch!
So you have got you want :)
I have had the same issue when enabling EqualizerAPO on my Focusrite 2i2 3rd Gen mic input. After removing it just from the mic, the distortion and dropouts stopped. It seems quite random as it works for most of the time but then it just breaks. Changing the buffer size even to 1024 does not fix it.
I've also experienced some audio hickups on the output since updating the driver and EqualizerAPO. I've switched from 48 kHz to 96 kHz now at 128 samples and it seems to be working now.
I mostly use EqualizerAPO on my gaming PC so 96 kHz definitely is not required and could cause other issues. But so far it seems to have fixed the issue. Though I have no idea why upping the sample rate at the same buffer size fixes it as it has to cause more CPU usage which seems counter intuitiv.
Also, using the GraphicEQ on the output never caused an issue for me. I only use shelf and peak filters and still had the issue. I tried switching the installation method but anything but LFX/GFX doesn't work at all
Last edit: Christoph Neuwirth 2024-02-14
You might try to unchecking of the "Use original APO" checkboxes. Perhaps an APO (audio processing object) of the Focusrite mic interferes with Equalizer APO.
Those are disabled by default for me. I can't even check them as they are greyed out
That's fine as there aren't any APOs which can mess things up. Unfortunately there isn't many things you can do. Of course SFX/MFX or SFX/EFX if you haven't tried this already.
Yes, it is although any CPU is fast enough nowadays to use 96 kHz or higher for that matter. Anyway, perhaps it's a sample frequency conversion issue?
Could be. Ive tried to use 48 kHz as this seems to be the default for most games and apps but it could be a sample rate issue. Maybe it happens when the primary CPU core is under heavy load or after some amount of time where it doesn't correct the mismatch. I will test further.
Maybe opting for a different audio interface where SFX works is also a good alternative. I really don't want to lose AutoEQ
Yeah, 48 kHz is more than enough but if you don't notice 96 kHz (as in a FPS drop) then things are okay. Anyway, let us know your findings.
Conclusion: the issue comes from the Focusrite drivers. I have no issues with the Universal Audio Volt 1 and once I've uninstalled the Focusrite drivers, I could use my Scarlett Solo 3rd gen without issue. So Focusrite's drivers are the culprit and not EqualizerAPO.
So either uninstall them or get another interface 😅
I've given up and sold my XLR iput stuff, to switch to USB. I was using it for live wencasts and it was just too unreliable.
What do you use now? The on-board headphone jack or another DAC? Just asking as the Focusrite Scarlett is a USB DAC anyways
I've bought a USB microphone and a headphone DAC/Amp.