Distortion of audio

Hi please help, installed Ardour6 on MacBook Air with Mtrack interface to record mixes from dj set up. I feel I have set up correctly using tutorials YouTube etc have audio going through software and I can record but there is a distortion on the audio. No matter what adjustments in volumes, preferences etc will rectify problem I have turned monitoring to hardware but still get crackle and distortion of music am I missing something obvious?

If you are doing monitoring through hardware, and still hearing distortion on the audio, that means that the problem is outside of Ardour completely (As that signal path doesn’t involve Ardour or your computer, just your audio interface and whatever is plugged into it).

Given that you mentioned a DJ set, my experience is that gain structure may be your primary issue, some DJ setups actually output stronger than line level as a ‘feature’ but the reality is that line level is a standard for a reason and it can cause issues with anything down the line if you don’t manage your gain properly. So the question becomes is ‘Is the audio clipping?’. If it is, it will show up in Ardour with red peaks while recording, and the answer is you either need to lower your input gain on your interface, or lower the output level on your equipment plugged into the interface.

If it isn’t an issue of the audio clipping, then more work may be needed to determine exactly what is causing the issue, but I would bet the above will address it, just a hunch with very little to back it up except my own personal experience.


Thankyou for your reply I went back and adjusted gains right down and no difference but the distortion or interference occurs every 8 beats or 2 bars does this ring any bells? If not I’ll not bother you more. Thankyou

Not off hand, but if this is really a musically timed event, something odd is going on. What equipment exactly are you running? Maybe someone here will have an idea or have used that equipment before.

And just to confirm you are actually monitoring audio through hardware, you can close Ardour and still hear audio correct?

Audio comes from pioneer cdjs and technics turntables to pioneer mixer then out through record terminals to m audio mtrack interface and then into MacBook. I definitely have monitoring through hardware I can hear it. I turned laptop speakers off to see if that helps but no. It actually works fine apart from a noise like crackle interference noise that occurrs every 2nd bar. The set up works fine with audacity and GarageBand. A mystery indeed???

Could it be that this is due to dropouts?

What settings do you use in Ardour’s Menu > Window > Audio/MIDI Setup?

Perhaps buffersize is too small? Try 1024 at 48kHz perhaps.

Are there any x-runs (buffer over/under-runs - there is a counter top-right in Ardour’s status bar, after the DSP load)?

Does the distortion occur if you monitor directly from the Pioneer mixer? Either from record terminals to your amp and speakers if you are using that, or the headphone jack if you are not using speakers.

Just to make sure you understand, in this context hardware monitoring would mean that you are listening at the headphone output of the MAudio, and the mix control is turned all the way to “Direct” and away from “USB.”
Also, is Ardour not running? For this part of troubleshooting you do not need Ardour running. You would not need the computer running at all except that the MAudio interface only gets power from the computer, there is not a way to power the interface separately.

Cheers guys I’ll persevere and try all the suggestions if I get a resolution I’ll be sure to post. Thanks for your time.

So for the record, as Chris mentioned you shouldn’t need ANY software if you are using hardware monitoring to listen to things, which means that it is likely you aren’t using hardware monitoring if the software is making a difference.

Given this, can you post a screenshot of your audio/midi setup window in Ardour as well when you get a moment? If this is a clicking happening about every couple of seconds, it is possible you have sample rate set incorrectly and what you are hearing is a digital sync issue. That is only one possibility however, and other suggestions @x42 made are likely quite appropriate to try as well in that case.


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