What causes a crackle momentarily, at louder peaks, when using a multi-effects pedal?

[Ally-007]

So I have a Sonicake Matribox multi-FX guitar pedal, that is generally well-regarded. Unfortunately, I often hear a crackle, momentarily at some higher peaks of the waveform, when using some effects combinations. It looks like it shouldn't be happening, because the level warning lights on my audio interface (Behringer UMC202HD) are not lighting up. So I'm guessing that some other part of the cirquitry chain is getting overloaded, momentarily, at those waveform peaks. I can sometimes get rid of it by carefully messing about with the gain staging of the effects modules in use in the pedal. But that can be time consuming, and often results in way less overall gain than what I need. Switching from 'instrument' to 'line' level input (or vice-versa) on the interface can also help, sometimes. Can anyone provide any insight into what causes this issue? Normal clipping, (caused, say, by increasing the gain control on an amp module or a boost/distortion module) just manifests as normal guitar distortion... but this is something more; I hear a momentary crackle/interference, at the loudest peaks, that can really mess up a recording, especiall when the guitar sound needs to be undistorted. Any insights would be much appreciated.

 

[DM60]

Even if the interface isn't clipping, you could still be clipping. Which is what this sounds like is happening. If you look at the wave and it peaks and is flat at the top, you have clipped. Turn the level down. You can increase the levels later.

One thing to remember, when reading about recording, the analog guys had to record hotter as any post recording gain introduced noise. Therefore, they tried to avoid increasing the gain and recorded hotter. In the digital age, we have the advantage to record lower and increase the gain as the digital world adds little additional noise (not enough to notice).

Turn your gain down, make sure there is no clipping (digital clipping is pop and clicks) and then add the gain in after the take. Other than getting a good clean take at good levels, you should not make your recordings hot. You can't fix a recorded clip.

 

[Ally-007]

Even if the interface isn't clipping, you could still be clipping. Which is what this sounds like is happening. If you look at the wave and it peaks and is flat at the top, you have clipped. Turn the level down. You can increase the levels later.

One thing to remember, when reading about recording, the analog guys had to record hotter as any post recording gain introduced noise. Therefore, they tried to avoid increasing the gain and recorded hotter. In the digital age, we have the advantage to record lower and increase the gain as the digital world adds little additional noise (not enough to notice).

Turn your gain down, make sure there is no clipping (digital clipping is pop and clicks) and then add the gain in after the take. Other than getting a good clean take at good levels, you should not make your recordings hot. You can't fix a recorded clip.

That's helpful, DM60 - thank you. From what you said, I'm guessing it is digital clipping then. That could be useful to know. Yes, your suggestion about reducing the levels on the audio interface, considerably below the level that the warning LEDs light up, does seem to work, sometimes. Does this digital clipping issue happen with most audio interfaces and multi-effects units? I would have thought they'd both contain some electronic provision to prevent it from happening.

 

[DM60]

Well, there are a lot of things that are going on. The makers of the tools give us what they think we need. Depending on the need, we may need more gain, or less gain. The indicator just shows you have exceeded the hardware limit. Don't look at it anything more than that.

Once you start adding tracks, you will have say 10 tracks, all below 0 and yet the master buss is showing clipping. That is now the result of multiple sound sources "adding" to frequencies that on each track alone, is fine, but 10 tracks all with a frequency that has 1 khz contained within each one, will add up to more that 0. Hence, clipping.

That is one reason (there are others) they have created compressors. But, that is also one of the reasons they created EQs (there are other reasons as well), to remove post recording frequencies that we don't want, either in a track (Example I remove a lot of frequencies on guitar below 400 HZ). Not a fast rule, just an example. That way, the instruments that I want to have "room" in the 400 HZ region (bass for example), has more space. And those instruments I don't want to have prominence in that area (EX. rhythm guitar) don't add to the frequency.

That is why they can't "provision" for this to happen. The manufacturers give us tools and we need to understand the tools to achieve the result set.

But know this, make sure you have a good clean sound coming into your track. Do not worry about how loud it is at the start (there are plenty of ways to push the loudness later). Let the target frequencies of each track have the room it needs and remove unwanted frequencies from the other tracks with your EQ. Look for the peaks in each track and tame them if needed with a compressor or "fader riding" (there are other ways to do that as well, but you will learn this as you go). Once you have everything gelling, then you start mixing, dialing each area in as your ears guide you.

I am probably not articulating this very well. There will be others that will come along and give a better explanation. Recording music is more complex than people realize. Keep asking and people here will guide you along the way.

 

[Ally-007]

Well, there are a lot of things that are going on. The makers of the tools give us what they think we need. Depending on the need, we may need more gain, or less gain. The indicator just shows you have exceeded the hardware limit. Don't look at it anything more than that.

Once you start adding tracks, you will have say 10 tracks, all below 0 and yet the master buss is showing clipping. That is now the result of multiple sound sources "adding" to frequencies that on each track alone, is fine, but 10 tracks all with a frequency that has 1 khz contained within each one, will add up to more that 0. Hence, clipping.

That is one reason (there are others) they have created compressors. But, that is also one of the reasons they created EQs (there are other reasons as well), to remove post recording frequencies that we don't want, either in a track (Example I remove a lot of frequencies on guitar below 400 HZ). Not a fast rule, just an example. That way, the instruments that I want to have "room" in the 400 HZ region (bass for example), has more space. And those instruments I don't want to have prominence in that area (EX. rhythm guitar) don't add to the frequency.

That is why they can't "provision" for this to happen. The manufacturers give us tools and we need to understand the tools to achieve the result set.

But know this, make sure you have a good clean sound coming into your track. Do not worry about how loud it is at the start (there are plenty of ways to push the loudness later). Let the target frequencies of each track have the room it needs and remove unwanted frequencies from the other tracks with your EQ. Look for the peaks in each track and tame them if needed with a compressor or "fader riding" (there are other ways to do that as well, but you will learn this as you go). Once you have everything gelling, then you start mixing, dialing each area in as your ears guide you.

I am probably not articulating this very well. There will be others that will come along and give a better explanation. Recording music is more complex than people realize. Keep asking and people here will guide you along the way.

Good insights and advice there, DM60 - thank you! Yes, I have struggled a bit regarding projects with many tracks (with several double-tracked tracks) and then getting the mixing right and the master level right, so I will definitely be referring back to what you said here. Thanks again!

 

[Deleted member 196982]

in a digital, multi-Fx device that is not using floating point data through its entire path, it’s possible to clip the input [internally] if you have the output of one digital effect have output that exceeds the level of the next one, but you still have the end output low enough that the level seen by the interface does not cause the clipping light to show up.

And there’s no doubt some latency in those lights that may let something slip through, but the peak dB for the track should show it being at 0.0 or above, if there’s no additional/DAW FX enabled. I’d just check your FX chain in the Sonicake and watch levels in a clean input as you build up the digital FX and keep adjusting the individual inputs and outputs to get a good level in the DAW.

Hope that makes sense.

 

[Ally-007]

in a digital, multi-Fx device that is not using floating point data through its entire path, it’s possible to clip the input [internally] if you have the output of one digital effect have output that exceeds the level of the next one, but you still have the end output low enough that the level seen by the interface does not cause the clipping light to show up.

And there’s no doubt some latency in those lights that may let something slip through, but the peak dB for the track should show it being at 0.0 or above, if there’s no additional/DAW FX enabled. I’d just check your FX chain in the Sonicake and watch levels in a clean input as you build up the digital FX and keep adjusting the individual inputs and outputs to get a good level in the DAW.

Hope that makes sense.

Thank you, Keith. I Thought I had found a way to overcome the issue: by setting the recording level on the audio interface to extremely low. While that works sometimes, to an extent, it also makes everything too quiet to hear what I'm playing, when recording, so I'm experimenting with what you said about making sure the level of one effect module doesn't exceed that of the next one in the chain. This seems to invove a lot of careful and time-consuming tweaking. I often give up and resort to switching to a completely different amp sim (for example) but maybe it's the answer. It's particularly of concern to me, as a lot of the recording I do requires non-distorted guitar sounds, and when an undistorded guitar piece displays an occasional noisy clipping, it really sticks out like a sore thumb.