Reduce distortion?

Reduce distortion?

[Rodolfo Medina]

Hi Jeremy, hi all...

I regularly use Sox to mix different audio channels, and I find it a fantastic
tool.

Now I did some piano home stereo live recording, and the playback reveals here
and there some distortion, probably because the microphones were too close the
piano strings.  Tomorrow I'll try to fix that error, but I like today's
recordings and am sorry to have to throw them away.  Perhaps can Sox help in
some way to reduce the distortion?  Or any other tool?  I suppose also a little
could be all right...

Thanks for any help,

Rodolfo


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Re: Reduce distortion?

[Dr. Thomas Tensi]

Hello Rudolfo,


you wrote:
 > I regularly use Sox to mix different audio channels, and I find it a
 > fantastic tool.

So do I.

 > Now I did some piano home stereo live recording, and the playback
 > reveals here and there some distortion, probably because the
 > microphones were too close the piano strings.  Tomorrow I'll try
 > to fix that error, but I like today's recordings and am sorry to
 > have to throw them away.  Perhaps can Sox help in some way to
 > reduce the distortion?  Or any other tool?  I suppose also a
 > little could be all right...

In principle it is hard to get rid of digital distortion.  With SoX I
would use some naive mixing trickery like selective low-pass-filtering
the distorted parts or mixing the distorted signal with a
lowpass-filtered and slightly compressed version.  This could mask the
critical parts somewhat.

You could also try a research project from the Georgia Tech University
called ClipAway from 2016.  I didn't try it myself, but the approach
looks interesting.  They have a web-site available where you can upload
your file and get it "declipped".

https://cplaguna-audio.github.io/ClipAway/

Maybe you can report your success (or failure)?


	Best regards,

		Thomas


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Re: Reduce distortion?

[Rodolfo Medina]

"Dr. Thomas Tensi" <t.tensi@gmx.de> writes:

> Hello Rudolfo,
>
>
> you wrote:
>> I regularly use Sox to mix different audio channels, and I find it a
>> fantastic tool.
>
> So do I.
>
>> Now I did some piano home stereo live recording, and the playback
>> reveals here and there some distortion, probably because the
>> microphones were too close the piano strings.  Tomorrow I'll try
>> to fix that error, but I like today's recordings and am sorry to
>> have to throw them away.  Perhaps can Sox help in some way to
>> reduce the distortion?  Or any other tool?  I suppose also a
>> little could be all right...
>
> In principle it is hard to get rid of digital distortion.  With SoX I
> would use some naive mixing trickery like selective low-pass-filtering
> the distorted parts or mixing the distorted signal with a
> lowpass-filtered and slightly compressed version.  This could mask the
> critical parts somewhat.
>
> You could also try a research project from the Georgia Tech University
> called ClipAway from 2016.  I didn't try it myself, but the approach
> looks interesting.  They have a web-site available where you can upload
> your file and get it "declipped".
>
> https://cplaguna-audio.github.io/ClipAway/
>
> Maybe you can report your success (or failure)?


Thanks you, Thomas...  At the address you report, I don't manage to load my
example...  I click onto `Load example' but nothing happens...  And also the
other buttons, all inactive for me...  Strange...

Rodolfo


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Re: Reduce distortion?

[Dr. Thomas Tensi]

Hello Rudolfo,

you wrote:
 > > > [distorted audio: how to clean?]
 > > [Try https://cplaguna-audio.github.io/ClipAway/]
 > Thanks you, Thomas...  At the address you report, I don't manage
 > to load my example...  I click onto `Load example' but nothing
 > happens...  And also the other buttons, all inactive for me...
 > Strange...

Hmm.  I opened the site in my browser (Firefox). When you click the
"Load Example" button some distorted demo file is loaded.  You can
declip it by pressing the "Declip" button.

I also managed to drag and drop a short wav file into the input area and
get it declipped.

So in principle this site seems to be working. Maybe you have to check
the audio format (I used WAV).


	Best regards,

                 Thomas


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Re: Reduce distortion?

[Rodolfo Medina]

"Dr. Thomas Tensi" <t.tensi@gmx.de> writes:

> Hello Rudolfo,
>
> you wrote:
>> > > [distorted audio: how to clean?]
>> > [Try https://cplaguna-audio.github.io/ClipAway/]
>> Thanks you, Thomas...  At the address you report, I don't manage
>> to load my example...  I click onto `Load example' but nothing
>> happens...  And also the other buttons, all inactive for me...
>> Strange...
>
> Hmm.  I opened the site in my browser (Firefox). When you click the
> "Load Example" button some distorted demo file is loaded.  You can
> declip it by pressing the "Declip" button.
>
> I also managed to drag and drop a short wav file into the input area and
> get it declipped.
>
> So in principle this site seems to be working. Maybe you have to check
> the audio format (I used WAV).


All right, with drag and drop it unlocked and I could try the web test...
Listening to it, it seems to me that Audacity does a better job...  Maybe I'll
be downloading the files from:

 https://github.com/cplaguna-audio/ClipAway

and give a more careful try...

Rodolfo


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Re: Reduce distortion?

[Dr. Thomas Tensi]

Hello Rodolfo,


sorry for misspelling your name in my previous posts!

> All right, with drag and drop it unlocked and I could try the web test...
> Listening to it, it seems to me that Audacity does a better job...

I assume you're using the "Clip Fix" effect?  Sorry, I didn't have
audacity on the radar in our discussion.

It would be interesting why the academic solution is worse.  They should
have tested it against more naive approaches...


	Best regards,

                   Thomas


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Re: Reduce distortion?

[Måns Rullgård]

"Dr. Thomas Tensi" <t.tensi@gmx.de> writes:

> It would be interesting why the academic solution is worse.  They should
> have tested it against more naive approaches...

Sometimes a naive approach works better once you stray from the
particular test set used to develop something more sophisticated.

-- 
Måns Rullgård


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Re: Reduce distortion?

[Rodolfo Medina]

Måns Rullgård <mans@mansr.com> writes:

> "Dr. Thomas Tensi" <t.tensi@gmx.de> writes:
>
>> It would be interesting why the academic solution is worse.  They should
>> have tested it against more naive approaches...
>
> Sometimes a naive approach works better once you stray from the
> particular test set used to develop something more sophisticated.


My too quick and hasty web test is probably not a valid one...  let's wait for
those files to be downloaded and installed, hoping installation is not too
complicated...

Rodolfo


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