Choppy sound recording a guitar using Mint 18.3 and a Line6 Pod X3 Live – Kernel issues?

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boodysaspie
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Choppy sound recording a guitar using Mint 18.3 and a Line6 Pod X3 Live – Kernel issues?

Post by boodysaspie »

PC specs are A8-7600 CPU, 16GB RAM, 128GB SSD boot drive and 1TB SSD data drive. I have a Line6 Pod X3 Live, which is a combo guitar effects pedal and USB audio interface.

I can install this in Windows 7 and I can record my "playing" into Audacity without any drops, so I’m happy that the pedal, software and the PC are up to the job.

Under Mint 18.3 and standard kernel I get tiny but frequent drops, as if the PC can’t keep up.

My first, and so far only, idea is to install a lowlatency kernel.

1) I ran sudo apt-get install linux-lowlatency which installed kernel 4.4.xxx-lowlatency (which is quite a bit older than the standard 4.15.xxx-generic).

Audacity doesn’t show the X3 as input or output. I ran lsmod which showed that snd_usb_line6 and snd_usb_podhd were not loaded. I modprobed them in, but no change.

2) I installed Ubuntu Studio to a spare disk. It has a 4.18.xxx-lowlatency kernel and both modules were installed.

My wireless mouse and keyboard were unusably slow, so I swapped those for wired versions. Audacity recognised the X3, but recording was completely garbled.

Grief-stricken, I sobbed myself into a fitful sleep.
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Is this a kernel problem or a module problem? Advice welcome, and thanks for reading.
Musicteacher
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Re: Choppy sound recording a guitar using Mint 18.3 and a Line6 Pod X3 Live – Kernel issues?

Post by Musicteacher »

Hi,

so you have a Pod and an USB Audio Interface.

On Windows, did you plug the analogue out of the pod into the analogue in of the usb audio , or did you record digitally with the usb of the pod?

On linux, you seem to try to record directly with the pod.

There could be a lot of things that are going wrong with your setup, it's hard to tell which is the case.

As far as I am concerned, I did not get my pod xt (which is a good deal older than your pod, but uses the same driver) to work with linux, so my conclusion is that the pod-driver is not working perfectly for everyone.

Would be using the analogue out of the pod into the usb device be an option for you?
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sysrqer
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Re: Choppy sound recording a guitar using Mint 18.3 and a Line6 Pod X3 Live – Kernel issues?

Post by sysrqer »

If they don't provide the version you need for the lowlatency kernel then you can build your own or install one from somewhere else. I recommend giving the liquorix kernel a try, it's easy to install and works well for audio and desktop use - https://liquorix.net/#install - that will give you 4.20 (at the moment) and gets updated regularly.

Are you using alsa? I'm not sure about how to configure that but jack is quite easy to adjust. I would recommend using cadence and catia from kxstudio repo, but you could use qjackctl with patchage.

There are a few tweaks you can make to make the system to tune it more for realtime audio, you could try the realtimeconfigquickscan https://github.com/raboof/realtimeconfigquickscan, this will give you a good idea of what could be improved.

Some more general setup advice - https://bcacciaaudio.com/2018/01/30/aud ... ack-audio/
Much deeper and more involved advice - https://wiki.linuxaudio.org/wiki/system_configuration
boodysaspie
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Re: Choppy sound recording a guitar using Mint 18.3 and a Line6 Pod X3 Live – Kernel issues?

Post by boodysaspie »

Thanks for the replies.

I avoided the issue by installing the latest version of Mint, 19.1, which has kernel 4.15.xxx.generic. The lowlatency app also installs the same version (except it's lowlatency) and now the dropouts are no more :D and I can't blame the horrid noise on anything but my playing :(

I can only assume somewhere that moving back from 4.15.xxx.gen to 4.4.xxx.low broke something :?

@Musicteacher - sorry, I confused you. I'm describing the X3 as a combo of both (effects and audio interface). I don't have a separate audio interface, and I connect the Pod to the PC with a USB cable. I think the only difference between XT and X3 is that the X3 has FX for guitar, vocals and bass, whereas your XT is guitar only?
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Re: Choppy sound recording a guitar using Mint 18.3 and a Line6 Pod X3 Live – Kernel issues?

Post by Musicteacher »

The Pod XT is guitar only, and it's still far older:

https://en.wikipedia.org/wiki/Line_6_(c ... ts_History

Also, the "live"-products are (as the name says) much better useable live (because of the pedalboard and controller) while having no real disadvantages on the other side.

Good that it works now!
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