Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

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Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by Michael Murray »

Attached is an audio sample of a live recording in a bar. I am using a USB to connect to a Behringer XR18. The music is being played through a PA system which does not exhibit any sort of distortion. I am a novice and would like help solving this issue, I appreciate any sort of advice in advance. Below is a link to the audio, the issue unpredictably occurs and then also unpredictably stops during recording.

https://www.youtube.com/watch?v=ERMQa_kfqfI
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Re: Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by Hugh Robjohns »

That's the sound of missing samples!

Possibly the computer's USB driver's buffer size is too small, or there is a clocking issue between the XR18 and DAW. Check which is selected as the master clock, and make sure the other one is slaved to it!
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Re: Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by Michael Murray »

Hugh, why would the issue resolve halfway through the clip and why do I have perfectly clean audio in many other examples?

I want to reiterate the fact that I am a novice/amateur and really have no idea what you are referring to in terms of clocking and buffer? I don't have intimate knowledge of sample size and the like. Thanks!
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Re: Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by blinddrew »

If it resolves halfway through that might suggest that there was a background process running on the PC that was using up CPU. Once that task finished there was enough processing power to run at the selected sample rate and buffer size.

Here's some very quick reading on:
Clocking: https://www.soundonsound.com/glossary/clocking
Buffer size: https://www.soundonsound.com/glossary/buffer
Sample rate: https://www.soundonsound.com/glossary/sample-rate

Roughly speaking...*
For clocking the key thing is that everything connected is running off the same clock. It doesn't really matter which one's the master and which is the slave as long as they're both correctly set.

For buffer size, the smaller the buffer the more processing power it's going to need and the more chance of drop outs if the computer can't keep up.

For sample rate, a higher sample rate means more processing power is needed.

* Smarter people will correct me / extrapolate later.
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Re: Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by Michael Murray »

Very helpful Drew thank you. Is there any way to repair this audio if possible ?
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Re: Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by blinddrew »

I suspect not unfortunately. You could try running something like Izotope's de-clip module and you might get a bit of improvement - but I wouldn't hold out a lot of hope I'm afraid.
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Re: Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by James Perrett »

Michael Murray wrote: Thu Jul 07, 2022 5:14 am Very helpful Drew thank you. Is there any way to repair this audio if possible ?

Only through very intricate editing of each individual section of good audio. There are thousands of sections that would need to be stretched and matched up which would take days (or weeks) of work. I don't think you could rescue it with standard de-click and de-crackle algorithms although they could improve it slightly.

Our lad has been playing around with frequency transforms in Snap! (vaguely similar to mp3 encoding) and the stuff I've heard him playing back has been remarkably good for such a relatively primitive process. So I'd maybe think about taking a Fourier transform of each section and then using those to synthesise a playback signal with the right timing.

However, if you value your time, it would certainly be cheaper and easier to re-record.
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Re: Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by Michael Murray »

Ok so I am going to simply try to reduce the buffer size and sample rate for my next recording session.

Right now I am using a laptop that has kind of just been laying about my house but going forward, I intend on purchasing something a little more robust to handle this issue while still capturing the highest quality audio. Should I just review the ProTools MAX system requirments, I didn't think it was a program which demanded much processing power and especially since I am not running any real time effects.

The other day I recorded a set where the musician had only one dynamic microphone and an acoustic guitar, the issue still occurred. I'm hoping if I just purchase a MAC or something of higher quality than I currently use, I can avoid this type of thing. I enjoy solving problems but I'm not terribly interested in devoting much more energy to this aspect of production.
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Re: Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by Wonks »

I think you meant 'increase', not 'reduce' the buffer size the buffer size.

If you are simply recording a complete live performance, and not recording whilst playing back to existing tracks, you don't need a small buffer size at all. Make it as large as it will go.
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Re: Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by The Elf »

Michael Murray wrote: Fri Jul 08, 2022 4:21 pm Ok so I am going to simply try to reduce the buffer size and sample rate for my next recording session.

That would be *increase* the buffer size, hopefully!

Also make sure you're using the native ASIO driver (not ASIO4ALL, or similar).
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Re: Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by James Perrett »

Quite a few people in the business use Reaper for live recording rather than Pro Tools. It is very lightweight and even my 18 year old Windows XP laptop can record 24 tracks simultaneously all night without a glitch with Reaper.
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Re: Distorted Audio, Behringer XR18 to ProTools via USB, Windows Computer

Post by Michael Murray »

James Perrett wrote: Fri Jul 08, 2022 10:12 pm Quite a few people in the business use Reaper for live recording rather than Pro Tools. It is very lightweight and even my 18 year old Windows XP laptop can record 24 tracks simultaneously all night without a glitch with Reaper.

I had to purchase a new laptop for my business recently and as a result have got to try running a live recording into ProTools to see if the same result occured. It did.

The feedback issue is even worse this time, in fact it doesn't intermittently resolve so I cannot extract any usable audio.

James, could you provide a link to the Reaper software which you deem is reliable? I think I am a little off put (perhaps unjustifiably) by the appearance of the website I am looking at on my side of things. Maybe I have the wrong link.
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