[Jackaudio] Noise when using JACK in Linux Mint

[Fabio G]

Thanks a lot for your reply, Patrick!
I will keep experimenting with different combinations of format settings.

About this:

> Do you have a "layer" between the drivers (alsa oss etc...) 

I am not sure of what you mean (I am not an expert :) ).
Of course the computer has alsa, but as far as I understand all the 
software involved (virtual keiboard, QSynth, JACK) are connected 
directly, without intermediaries.
Can you give me some tests to do, to determine whether there is a layer 
in between or not?

Again, thanks a lot!

Fabio

On 2022-11-28 13:16, Patrick Pouget wrote:
> White noise is, in general, due to format mismatch. I mean data types, 
> sample rate, number of channels etc...
>
> I can see 2 causes
> * Jack should be queried for the format by the application. If you 
> have the problem with many, it is not the case
> * jack relay on drivers that return wrong informations or no 
> information or a default information. Do you have a "layer" between 
> the drivers (alsa oss etc...) and jack?
>
>
> On Mon, 2022-11-28 at 09:14 +0100, Patrick Pouget wrote:
>> White noise is, in general, due to format mismatch. I mean data 
>> types, sample rate, number of channels etc...
>>
>> I can see 2 causes
>> * Jack should be queried for the format by the application. If you 
>> have the problem with many, it is not the case
>> * jack relay on drivers that return wrong informations or no 
>> information or a default information. Do you have a "layer" between 
>> the drivers (alsa oss etc...) and jack?
>>
>>
>>
>> On Mon, 2022-11-28 at 09:03 +0500, Fabio G wrote:
>>> Hello to all!<https://sound.stackexchange.com/posts/51899/timeline>
>>>
>>> I am experimenting with audio production under Linux Mint 20.3  
>>> (based on Ubuntu 20.04). I managed to install a low latency kernel, 
>>> then I have installed JACK, and Qsynth, following the steps 
>>> described in this tutorial:
>>> <http://www.tedfelix.com/linux/linux-midi.html>
>>>
>>> http://www.tedfelix.com/linux/linux-midi.html
>>>
>>> <http://www.tedfelix.com/linux/linux-midi.html>Everything seems to 
>>> work fine if I use Qsynth and pulseaudio: I use the vmpk simple 
>>> virtual keyboard, and I have good output sound.
>>>
>>> I have also tested JACK, as suggested in the tutorial using
>>>
>>>
>>>> $ jack-play test.wav
>>>>
>>> and I hear the right clean output.
>>>
>>> However, when I tell Qsynth to use JACK, I have a lot of noise. When 
>>> I hit a key I have "white noise" for few milliseconds instead of the 
>>> key sound, and only when it fades I have a little bit of the note 
>>> that I was supposed to play.
>>>
>>> I have the same "white noise" problem is I use Rose Garden.
>>>
>>> I have tried to change the sample rate and the frames/period 
>>> settings, and also the Timeout, in JACK, but the problem stays the same.
>>>
>>>
>>> Thank you in advance for any help you can give.
>>>
>>>
>>> Best,
>>>
>>>
>>> Fabio
>>>
>>> _______________________________________________
>>> JackAudio mailing list
>>> JackAudio at lists.linuxaudio.org
>>> https://lists.linuxaudio.org/listinfo/jackaudio
>>
>
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