Notes beginning and ending abruptly

[meddelhed]

I've just started trying out Ubuntu Studio, coming from Ubuntu previously.
The following thing is happening using jack1.9 with qjackctl, and guitarix.

First, a picture:

What we see here is a recording made in Ardour 7.2 of the output of guitarix, where I played a few notes. The visible thing is less than 3 seconds.
The notes are in fact played with a slight staccato, but we all know that it shouldn't look chopped off like it does. There should be more of a visibly diminishing transient.

The problem is not with ardour, as I can quite clearly hear it happening while playing through guitarix. It affects staccato notes, but also notes that are not really staccato, but they are in some weird way; for example in quick picked runs - fingers move quickly enough on and off the strings.

At first I thought it was an issue with the noise gate in guitarix, but switching it off makes no difference. I've also increased the preamping on my audio interface, to no avail. Jack does not detect any drops, i.e. xruns or something like that.

Does anyone have any idea what the cause could be? Or how we can find out?

[meddelhed]

Yes, I wrote above:

At first I thought it was an issue with the noise gate in guitarix, but switching it off makes no difference. I've also increased the preamping on my audio interface, to no avail. Jack does not detect any drops, i.e. xruns or something like that.

I actually copied the working guitarix configuration from my old system over to the new one. On the old machine, it worked perfectly fine. Same guitar, same interface, same cables.

[tseaver]

I don't make much use of gates, but the waveform surely looks like one where an aggressive gate is being used.

Fault isolation steps (you may have tried these already):

• Does the "gate" effect happen if you record the dry signal (without Guitarix?)
• Does the "gate" effect happen if you record using one of the "stock" Guitarix presets?
• Does the "gate" effect happen if you record after re-enabling the gate, after turning its threshhold as low as possible?
• Do you have any outboard gear in-line which might be affecting the signal path?

[meddelhed]

Didn't even think of some of these steps but

• Does the "gate" effect happen if you record the dry signal (without Guitarix?)
• Does the "gate" effect happen if you record using one of the "stock" Guitarix presets?
• Does the "gate" effect happen if you record after re-enabling the gate, after turning its threshhold as low as possible?

Yes to all of these

• Do you have any outboard gear in-line which might be affecting the signal path?

I'm using a Focusrite Scarlett Solo. But 7 days ago, there was no problem on my old computer with it. But I cannot check right now if it still works normally on my old system.

I have tried all possible (to me) combinations of

• instrument cables
• guitars
• noise gate settings in guitarix
• whether to bypass guitarix or not

and it still persists.

I can play through my amp and not have the issue, which hints at the problem sitting between the audio interface and the way audio input is handled on my laptop.

[Michael Willis]

Just throw a good plate reverb in after it and the sudden cutoffs will magically go away.