[Solved] Clip Zip audio quality improvements

[music_lover001]

In recent days, according the change log, some audio quality improvemnts were added to the latest builds for the Clip Zip.  I now notice that, when hitting play on the Clip Zip, there is a popping noise.  It was their before, but it is much more noticable now.  I have also noticed a popping noise infrequently when going through folder view, or the other menus.  I have also heard some popping (very infrequently) during playback.Has anyone else noticed this?  If so, have you come across a work around?Thanks to all the people that have made this possible!  Rockbox is a terrific project.
Thank you in advance for any assistance.

[saratoga]

I haven't noticed anything (but i didn't notice this before either). 

[Mihail Zenkov]

music_lover001:
You hear pop-click noise only when volume >= -40dB? I can hear small clicks on start/stop playing with low impedance headphone and don't hear it on high impedance headphone.  I try to find workaround for this behavior.

[music_lover001]

Thank you for any help.  All my headphones are low impedance, and one of them is also more sensitive, and of course the clicks (or popping noise) is more noticable with the more sensitive headphone.  And as was pointed out, the volume is > -40dB.

For the moment, I am using an older build.

Once again, thank you.

[saratoga]

I don't think you actually answered his question.  Do you hear a pop-click noise only when volume >= -40dB?

[music_lover001]

Sorry about that.

For some reason, my headphones need to be > -40db with the Clip Zip (I have noticed the volume levels are up there as well with Sansa's firmware).  If it isn't that loud, then the volume is too low (classical music and wide dynamic range?) and the quieter passages of the music are inaudible.  Even with the more sensitive headphones, the volume is in the -35dB through -38dB range.
On a side note, I also have a Sony NWZ-E465.  I can easily listen to that with the volume under half (12-13).  In addition, I also have a Clip Sport, and the volume needed for the headphones is lower yet.

Once again, thank you.

[Mihail Zenkov]

music_lover001:
Can you set volume to -41dB and check clicks on play/stop with latest rockbox? After that try set -40dB and check again.

[music_lover001]

music_lover001:
Can you set volume to -41dB and check clicks on play/stop with latest rockbox? After that try set -40dB and check again.

After checking this out, I found at -41dB the clicks disappear, and at -40dB the clicks reappear.  Interesting (Spock might say "fascinating").

Thank you again.

[Mihail Zenkov]

music_lover001 was right - rockbox without patch also have this problem but clicks not so sharp.
Step to reproduce:
1. get most sensitive headphone
2. play very quiet music (pianissimo or dithering test)
3. set volume +6dB
4. press play/pause

As this player don't have de-coupling capacitors, we have great sound quality, but also pop-clicks problem when we on/off some audio parts or change settings in it.
At now, rockbox don't shutdown output stage on pause (it impossible without clicks). But it shutdown DAC clock (I2SO MCLK) and we can hear this clicks. I attach patch to change this behavior.  Drawback: +2mA consume at pause.

[saratoga]

Is there a click when the headphone output is muted?  Maybe it would be possible to start muted and then raise the volume?

[Mihail Zenkov]

No, I two days test all possible variation without success.

[music_lover001]

music_lover001 was right - rockbox without patch also have this problem but clicks not so sharp.Step to reproduce:1. get most sensitive headphone2. play very quiet music (pianissimo or dithering test)
3. set volume +6dB
4. press play/pause
As this player don't have de-coupling capacitors, we have great sound quality, but also pop-clicks problem when we on/off some audio parts or change settings in it.
At now, rockbox don't shutdown output stage on pause (it impossible without clicks). But it shutdown DAC clock (I2SO MCLK) and we can hear this clicks. I attach patch to change this behavior.  Drawback: +2mA consume at pause.

Mihail Zenkov:  I would like to thank you for the time you put in on this.  Unfortunately, I do not have any way to access the source code, except at work (which would not be a good idea).  While I have built software using the source code in the past, I have always been able to download a gzip of the source, which does not seem avaible.  Am I correct in assuming that an option in the "Settings" menu would not work in this case?
Once agian, I thank you for your time and efforts.

[Mihail Zenkov]

Mihail Zenkov:  I would like to thank you for the time you put in on this.  Unfortunately, I do not have any way to access the source code, except at work (which would not be a good idea).  While I have built software using the source code in the past, I have always been able to download a gzip of the source, which does not seem avaible.

Build for zip with this and others my latest patches (http://forums.rockbox.org/index.php/topic,48549.135.html)
http://gdurl.com/c_OQ/download

Am I correct in assuming that an option in the "Settings" menu would not work in this case?

No, it should work like early.

[music_lover001]

Mihail Zenkov:  Thank you, thank you, thank you!  I do not think that I can put into words my gratitude for your assistance.  My thanks for your time in determining the problem, and figuring out how to fix the problem with a patch.  Then you went above and beyond and made a build that I could use.  Your solution has fixed the issue I mentioned at the beginning of this thread.  Thank you!  A clarification question:  at first, you mentioned that headphones with a lower impediance are more likely to hear this popping noise, then later mentioned that high sensitivity is the factor.  Is it the impediance, sensitivity, or possibly a combination of these two things?One last item.  I do not know who makes such decisions, but would it be possible to have this patch added to Rockbox for the Clip Zip?Again, thank you!

[Astrogoth]

A reboot solved the whine/buzz I heard in my Zip. Sounds great now.