[Sansa Clip+] Buffering noise (different, but present with and without Rockbox)

[Kalith]

Hi,

First I'd like to say that I'm really impressed by the work you've put into those firmwares, so in advance : thank you, and congratulations.

Now let me tell my story from the beginning.

I got my Sansa Clip+ just yesterday, and immediately fed it my favorite FLAC tracks for testing. I was very disappointed : at low volume, I could very well ear a "ticking" (a bit more than one per second) that is of course not usually present in the song. This ticking doesn't show up with the original MP3 songs that are shipped with the Clip+. Further tests showed that these ticks disappeared if I put my FLAC songs on the (16Gb Kingston class 4) uSD card instead of the internal memory.

I had already eared about poor FLAC support with the original firmware (heavy battery consuming), and also eared that Rockbox was the solution for this.
So I installed it (v3.10) in 5 minutes and ran the test again. The ticks were gone, great ! But I had another problem : every time a song starts (would it be MP3 or FLAC), I could ear a very unpleasant noise (kinda like the CPU/GPU noise you sometime ear with computers) that would last for 1 second and vanish. Furthermore, as FLACs are rather large files, it seems that Rockbox doesn't read them all at once in the RAM, but rather buffers ~1min at a time. This results in several ~1sec CPU noises during the song. This CPU noise is present with songs that are either in internal memory or the uSD card. I've tried to change many settings in Rockbox (fade-in/out, library to RAM, statistics recording, automatic database updates, ...) with no luck. It also appears whether I'm on the "now playing" screen or in the menus.

This noise makes Rockbox unusable for me, as I enjoy listening to music with low volume
My current solution is to use the original firmware, and only put my FLACs in the uSD card (leaving the internal memory for MP3s for example). This is working good, but I know I'm also missing something by not using Rockbox...

Note that I've also tested the very latest build (as of writing) and it show the same behavior.
Are you aware of such problem ? Is there something I need to do to fix it ?
Is there a chance that this might be cause by a faulty hardware ?

I've searched the web for similar cases, and although I found several threads about noise, none was really the same as mine.

Anyway, thank you very much for your time, and merry Christmas

Additional informations :

• Both noises (with and without Rockbox) are volume independent, and best eared with volume set to zero.
• Both noises can be eared with the stock earbuds and with my Creative EP-630 earbuds.

[saratoga]

http://www.rockbox.org/tracker/task/11907

[Kalith]

Yes I saw this one too. But as you can see, it's the reverse problem : he's fine with internal memory but not with the uSD card. I'm no expert in this domain, you think these two problems are related ?
The noise I ear with Rockbox is independent of the uSD card (i.e. I can ear it as well when the uSD card is removed). I ear it as well when the player boots up or shuts down, and on several other occasions (for example when doing a background update of the library etc).

Edit : I should also add that I also ear a very short noise with the original firmware and FLACs files on the uSD card. Because of its extremely short length (< 10ms maybe), it is almost unnoticeable though, and only happens at the beginning of each song.

I've made some additional tests : the "tick" noise I was earing with FLACs on the internal memory also happens with MP3s. It is almost constant (that's why I didn't notice at first).

[saratoga]

Yes I saw this one too. But as you can see, it's the reverse problem : he's fine with internal memory but not with the uSD card. I'm no expert in this domain, you think these two problems are related ?

According to that task, it can happen with either internal or external memory, so its probably the same problem.

[Kalith]

Ok, I'll just watch this ticket for updates then. I can live with the original firmware for a while

I would gladly help with the code, but I've no experience on that kind of programming. So if you need anymore detail (about the songs, about the player, noise recordings, ...), just let me know, but I doubt I'll be able to do more to help.

Thank you for your time.

[Vestibule]

Same problem here ...
Made some little tests and obviously the issue is related to the transfert rate of the uSD card.
This noise is audible with my 32 GB Class 4 Sandisk ... but nothing (or less - less noticable noise) on my old 8GB Class 2 PNY.