Guitar distortion has become harsh and I don't know why

[Nachei]

I used to get a recorded distorted guitar with a tone that I was happy with, distorted yet controlled:

https://www.dropbox.com/s/3mqbvo84dq8hw ... D.wav?dl=0

I just used Guitarix with one of its default settings (been a while and didn't document it, but I'm 99% sure it was kokoko3/dist2). It worked out of the box and I didn't have to tinker at all.

Then at some point the guitar sound changed:

https://www.dropbox.com/s/iqlglaqd5t4v4 ... D.wav?dl=0


It's like it became more "grainy" and harsh, with a lot of harmonics out of control, specially in the high frequencies. Changing the guitar switches and knobs does not make much difference. Applying EQ in the daw does not improve the sound (unless I do some radical changes and then the sound becomes "telephonic-ish", unusable).

At first I thought it was perhaps because the strings were worn out, but changing them didn't help. I tried a lighter gauge (reasoning that bigger strings have more inertia and can be noisier...), no change either.

I also tried all kind of parameters in Guitarix and Jack (see my previous posts in this forum). A lot of enlightenment on audio maters, but no improvement on my guitar side.

So, escalating the problem, I finally thought of some mechanical problem with the guitar, and took it to a revision to a luthier. He made a refretting and adjustment of truss rod and intonation.

I thought that would be the end of it, but alas; the guitar now is way more comfortable and easy to play, granted, but the sound keeps being harsh (clip 2 was recorded after the visit to the luthier; again with the setting kokoko3/dist2).

My tests have also included: 2 different laptops, 2 different audio interfaces, and 3 different daws. I've tried everything I can think of and I'm at a loss with this problem. Do you think of some other factor I could try? Thank you for any idea you could have.

[tramp]

Hi

From your last thread I know you are using a older version of guitarix, have you updated guitarix since then? Which version do you use?

[Nachei]

Hi, thank you for replying...

The Guitarix version I use is 0.34.0 When you mentioned it in the previous thread, I looked into updating Guitarix, but it seemed not an easy task, I didn't really understand the process; the information I found mentioned that first you had to uninstall manually your current Guitarix, there was a whole list of dependencies to handle... As I'm using the Guitarix that shipped with my distro (Ubuntu Studio 16), and I intend to move to another distro in the future, I gave up, afraid of breaking something, but if you could point me to some tutorial that my power user abilities can handle, I'll be glad to give it a try...

In any case, in that round of tests what I did try was using a newer Guitarix version via an AVLinux live DVD. It didn't occur to me to get the number version of Guitarix, but it has to be more modern than my current one because it had the modern layout, with the green colors and the round knobs. Didn't seem to make any difference in the sound.

For what is worth, one thing I'm observing in my tests since I wrote the post is that the sound improves when I use a compressor. The clip with correct sound has a clear "tube" shape, with no spikes, while the other is more spikey. I don't know why this happens, because like I said I use default settings in both cases, but in any case now I'm getting better, more controlled results when I put Guitarix's compressor before the amp head, and give it low threshold, attack and release values. It still has more fizz than it used to, but it is borderline usable...

Anyways, thank you for your help

[tramp]

The Guitarix version I use is 0.34.0 When you mentioned it in the previous thread, I looked into updating Guitarix, but it seemed not an easy task, I didn't really understand the process; the information I found mentioned that first you had to uninstall manually your current Guitarix, there was a whole list of dependencies to handle... As I'm using the Guitarix that shipped with my distro (Ubuntu Studio 16)

You may just add the KxStudio repository's :
https://kxstudio.linuxaudio.org/Repositories

then you'll be able to simply update (apt-get or synaptic) your guitarix version to a more recent version.

For what is worth, one thing I'm observing in my tests since I wrote the post is that the sound improves when I use a compressor. The clip with correct sound has a clear "tube" shape, with no spikes, while the other is more spikey. I don't know why this happens, because like I said I use default settings in both cases, but in any case now I'm getting better, more controlled results when I put Guitarix's compressor before the amp head, and give it low threshold, attack and release values. It still has more fizz than it used to, but it is borderline usable...

Maybe, your input level is to high, use alsamixer, select your soundcard (F6) and check the input (capture) levels (F4). There should no boost been enabled, and levels shouldn't be higher then 70%. You could lower the input levels during play with guitarix, to find a setting which suite your needs . Check as well that your connections been right, (don't connet gx_amp to system out).

Other then that, I've just published a new plug, GxDenoiser2.lv2, which is a filter to avoid noise, harsh inputs.
With a more recent version you could load it into guitarix (I ain't remember if 0.34.0 already has LV2 support).
You can get it here, the build/install process is easy.
https://github.com/brummer10/GxDenoiser2.lv2

regards
hermann

[Nachei]

Thank you so much for the instructions... Upgrading Guitarix was a breeze, and it will remain that way from now on...

I checked alsamixer. My audio interface (Samson Gtrack) only has one control, "PCM". Indeed it was at 100%, so I reduced it to 70%, but it didn't seem to change the sound.

This test, however, is not definitive, as all I did was recording a guitar track with Guitarix in Audacity. It seems the install did break something: now when I try to execute my DAW (Reaper), I get "segmentation fault (core dumped)". Never happened before.

So it'll take some time before I have everything running again and can check things for good: to complicate things, my audio interfaces (the aforementioned G-Track, and a Lexicon Alpha) have both this rare disease sometimes USB powered devices get of "USB whining". At least I think that's what it is - an annoying high pitched sound in the background that ruins all the takes.

After doing all kind of tests, I've decided to get a new interface; my main candidates are the Focusrite Scarlett 2i2 and the Presonus AudioBox 2x2. I think I'll get the Focusrite because I've seen posts of weird things happening with Linux support on the Presonus. Any recommendation among these, or maybe other models? Of course I still have to make the due research in this forum, etc...

These were two different problems (one the "whining" and other the harsh guitar tone), but who knows, maybe they are connected and instead of fiddling what I need is updating my gear... I'll post my results -also the tests with the denoiser plugin- once I'm at the other side of the changes...

(What you gonna do, it seems 2018 is the year I ran out of beginners' luck with my gear... )

[Nachei]

Hi, it's me again. In this time tried to move to AV Linux but it didn't work well in my system (~1 minute to boot, lost wifi, etc...), so I finally moved back to Ubuntu Studio.

Therefore I haven't been able to update my Guitarix version (let it be known in the world wide web: updating Guitarix in Ubuntu Studio 16 breaks Reaper -and the problem is specifically with the Guitarix update step; you can add the KX repositories and Reaper works without problem).

So I've been continuing my struggle to get a usable guitar tone and here's where I'm at. I've finally got something that can be usable, I think what did the trick was lowering the guitar's pickups and disabling all the stereo effects in Guitarix.

However, the problem I'm facing now is that I get a strange suction sound whenever the notes stop (see clip). It happens in all the pickups, and with different Guitarix settings. Having the noise gate on or off makes no difference. The amount of drive does not make any difference. (The first part of the clip is with full drive, the second with none). This effect is particularly noticeable when playing palm mute. Any idea of why this could be? Thank you for any help.

https://www.dropbox.com/s/tg7q14efganz3 ... e.ogg?dl=0

[tramp]

You should really use 48kHz instead 44.1kHz with guitarix.

[Nachei]

Yeah, I've tried using 48000 several times along this process and didn't seem to help. I've usually used more often 44000 for "legacy" reasons (the project was started with that rate, and changing it halfway was a mess), and because 48000 gives a slightly superior latency, but I'll keep in mind the recommendation for the future...

I really appreciate all your efforts to help; putting the subtleties of this bitch into words bores me to tears, I can only imagine what it will be like for the people on the receiving end, who don't have "skin in the game". I'm thinking that maybe an internet forum is too coarse of a tool for this "rare disease" my sound seems to have. I've purchased a new interface recently and it hasn't improved the situation, so that leads to think that the problem is guitar or laptop related; so now I'll move to try changing pickups, running AB tests with different gear... Thank you again for your generous help with this drag

[tramp]

so that leads to think that the problem is guitar or laptop related; so now I'll move to try changing pickups, running AB tests with different gear...

What about Rakarack, have you tried it? Do you get similar results there?

[Tenaba]

You should really use 48kHz instead 44.1kHz with guitarix.

While I don't have the problem mentioned in this thread, could I get some elaboration on why 48kHz would be preferred over 44.1kHz? Is this still the case when working on a project in 44.1kHz?

[tramp]

We using IIR filters in guitarix, those been designed for 48kHz. Also for most non-linear parts we using "oversampling" to a fixed 96kHz rate, because that gives the best results in our tests. Unfortunately resampling from to 44.1kHz/96kHz could introduce errors, which may not sound so nice as it could be.
For best results 48kHz is preferable when using guitarix.
You could surly use 44.1kHz, or what ever you prefer, when the result suits your needs, but, I would suggest to use 48kHz in any project you plan to involve guitarix plugs.

[AlexTheBassist]

You should really use 48kHz instead 44.1kHz with guitarix.

While I don't have the problem mentioned in this thread, could I get some elaboration on why 48kHz would be preferred over 44.1kHz? Is this still the case when working on a project in 44.1kHz?

The reasons are multiple. Aside from tramp already told, there's some more. First of all, most of USB interfaces have their internal clock (if they do have it) at 48, 96 or 192 KHz, so you get the least jitter possible with those sample rates. Secondly, this way you get better performance via USB, because the only “native” mode for an interface is its maximum sample rate, which in almost all cases is, again, a multiple of 48K. Third, with 48K you get less roundtrip delay, because sample per buffer value is set independently of sample rate, and, with HPET, you benefit even more than a fraction of a millisecond. On my system, the total roundtrip difference between 48K and 44.1K was about 5-6 (!) ms, which is noticeable for any non-deaf rhythm section player. I'd even re-measure to get exact value it if I wasn't that lazy and busy, but you can check it for yourself using jack_iodelay and a suitable cable to feed the sound from your output back to input. Fifth, if you're making a video with Guitarix, it's recommended to use 48K sample rate in your sound track, because it became a de facto standard for videos since DVDs.