Constant clicking problem (ipod 5g)

[PinkZeppelin]

Is it normal for the DAC to make a moderately loud popping noise when shutting down rockbox?

[PinkZeppelin]

Also there seems to be a constant low background clicking noise.  Turning the volume up also creates a louder clicking noise that occurs whenever I move around the scroll wheel.

I am using an Apple 5G

[PinkZeppelin]

Well, the DAC popping on shutdown occurs in the Apple Firmware as well, so I guess it isn't a rockbox thing, so it is really a non-issue.

But the low clicking noises and wheel moving noises do not occur in the apple firmware. 

Does anyone else hear the low constant clicks and wheel movement clicks in rockbox?

[linuxstb]

Well, the DAC popping on shutdown occurs in the Apple Firmware as well, so I guess it isn't a rockbox thing, so it is really a non-issue.

Just because the Apple firmware also has a certain bug doesn't mean we shouldn't try to fix it in Rockbox...

But the low clicking noises and wheel moving noises do not occur in the apple firmware. 

Does anyone else hear the low constant clicks and wheel movement clicks in rockbox?

Some people have reported this before - but others (including me) don't experience it.  What iPod do you have, and what kind of music files (format and bitrate) ?  Do you get those clicks with all your files, or just some?

[PinkZeppelin]

Some people have reported this before - but others (including me) don't experience it.  What iPod do you have, and what kind of music files (format and bitrate) ?  Do you get those clicks with all your files, or just some?

I am using an Ipod Video 5G (black), virtually all my music is in Wavpack, but the clicking starts right after the unit is turned on, regardless of codec. 

The sound is a constant, quiet and rhythmic clicking and seems to only occur on the right side of my cans (Sennheiser 280Pros).  The wheel movement noise is easy to reproduce - pause music,  then turn up the volume.  I start hearing a faint clicking noise (this noise also seems only to be in the right channel of my headphones) while moving the wheel when I turn the volume to -11db.  Increasing the volume further makes the wheel noise much more pronounced, and also increases the rhythmic clicking volume. 

[obo]

I've put a patch together to stop the pop on shutdown.

http://www.rockbox.org/tracker/task/4819

[PinkZeppelin]

Anyone have a solution to (or can confirm) the problem with the constant low clicking noises? 

[PinkZeppelin]

has anyone investigated? 

[PinkZeppelin]

I wrote up a bug report:

http://www.rockbox.org/tracker/task/4937

[PinkZeppelin]

No responses? 

Using RMAA, I analyzed both the apple firmware and the rockbox firmware on my 5G.

Results:


Original Apple Firmware:



Rockbox Firmware:



It is easy to see the constant low clicking here in the rockbox firmware.

Same picture (Rockbox Firmware) with the clicks circled:



The pictures are resized above, and may be a bit hard to see.  Unresized links:

Apple Firmware:
http://img93.imageshack.us/img93/9042/applefirmwarec6xy.png

Rockbox Firmware:
http://img63.imageshack.us/img63/9149/rockboxc3mf.png

circled:
http://img148.imageshack.us/img148/2394/rbhighlightc6ky.png

The clicking does only seem to be coming from the right channel, as these pictures show.

Others should be able to see, hear, and do these same measurements as well. 

Comments?

[lostlogic]

As we discussed on IRC, I believe this to be related to our slow I2C implementation, and occurs when the battery status and/or realtime clock are updated (the battery is read at up-to 2.5hz and the clock at up-to 1hz).  Nothing is going to change with it until someone spends a lot of time analyzing the portalplayer's I2C control registers, or finds a datasheet for the damned thing.

[TREX666]

So rockbox will never run as fast as it should with the current I2C implementation. Unless Portalplayer hands over datasheets

[PinkZeppelin]

damn, it looks to be a lot of work to fix the problem.  I dearly hope someone is willing to go through the code or find the datasheet. 

Because of the background clicking problem, I have reverted to using the apple firmware w/ 1 giant, inefficient apple lossless file per album (due to lack of gapless playback). 

Needless to say, it sucks.

I pray someone will be able to fix this...

[lostlogic]

Going through the code won't help -- I've been through it... this involves either getting the datasheet, or disassembling the apple firmware, or painstakingly trying bit combinations to control the portalplayer i2c driver.

I for one can't detect the clicking no matter what volume I use on my shure E3 in-ear monitors, so I can also suggest using a lower impedance pair of earphones.

[PinkZeppelin]

i was able to detect the constant clicking easily with my EP-630s when turning up to otherwise earsplitting volumes - but, as said before, could hear it at normal listening volumes on my HD280 pros.   

Now, if you arent able to hear it at the highest volumes, maybe it was a problem with my player.  If you record back your ipod in rockbox playing the RMAA file, normalize if needed, then check the spectral graph of the file, then it would answer that question.

Nevertheless, I returned my 5G.  I was bothered by the clicking in the rockbox firmware and the lousy apple firmware.  I still have my H140, but there is deep bass hum whenever the harddisk spins in the rockbox firmware (ill run RMAA tests and make a thread in the appropriate section later). 

Because of the sound noise problems I have found in both flavors of rockbox (both on my H140 and the Ipod 5G), and the fact that even some people (including at least 1 rockbox developer) seemed to think the X5 sounded fine when it was playing back with a 10khz lowpass filter make me a bit skeptical about rockbox audio quality claims...