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Constant clicking problem (ipod 5g)

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PinkZeppelin:

--- Quote from: lostlogic ---The only claim I know of that rockbox makes about audio quality is that unlike many stock firmwares, we do not futz with the audio output of the codec, we simply play it back to the hardware as is (unless you turn on the various 'enhancement' options available).

As for the H140 buzz, that occurs with stock and rockbox firmwares as far as I know (at least it did on my H340), so don't try to pin that on rockbox, it's a problem with isolation on the iRiver players.

Finally, I do not doubt that the clicking problem occurs, as I said, we have a known issue with our I2C driver which could cause such a problem.  When using Rockbox, you need to realize that it is a _free software_ project.  It is developed for fun.  If you have a problem with it, fine, but don't act _entitled_ to a fix or  change to rockbox behavior.  You are more than welcome to develop your own solution, as the source is there for your modification.

I (unfortunately) do not have the software, hardware, nor knowledge to do RMAA analysis of my player, but I would be interested in other datapoints on the clicking issue.
--- End quote ---

I just ran some tests on my H140 and the bass hum does indeed to effect both original and rockbox firmware, so I did erraneously pin that on rockbox. 

I am not upset at rockbox development, I am just upset when people claim that the audio sounds fine when it is not true, or when I make threads like this and don't get answers until I actually measure the problem.  It would have been nice to know that the H140s had a buzzing problem before I purchased it last year (but that is not really anyones fault).


--- Quote from: saratoga ---Anyway, MP3 lowpass is configurable, but the spec clearly intends you to use no higher then ~15-16KHz, not 18KHz.
--- End quote ---

I don't think that is quite right.  Using the standard (and recommended) Lame 3.97b encoding setting, the resulting mp3s have a lowpass around 19khz.


--- Quote from: saratoga ---Its perfectly reasonable that many people using Rockbox would never notice a 22Khz sample rate, even listening to lossless audio.
--- End quote ---

I think virtually nobody could discern anything above even 18khz, which is why many lossy encoders aim at transparency by using a lowpass around those frequencies.   


Nevertheless,

Thank you lostlogic for explaining the clicking problem.  I'm now looking into a purchase of an X5, just need to have someone post a spectral view like I did to confirm that there are no audio anomalies.

saratoga:

--- Quote from: PinkZeppelin on April 01, 2006, 04:08:10 PM ---

I am not upset at rockbox development, I am just upset when people claim that the audio sounds fine when it is not true, or when I make threads like this and don't get answers until I actually measure the problem. 


--- End quote ---

Then you're welcome to hire someone to document your bug reports for you. 


--- Quote ---
--- Quote from: saratoga ---Anyway, MP3 lowpass is configurable, but the spec clearly intends you to use no higher then ~15-16KHz, not 18KHz.
--- End quote ---

I don't think that is quite right.  Using the standard (and recommended) Lame 3.97b encoding setting, the resulting mp3s have a lowpass around 19khz.

--- End quote ---

Not to be an ass, but read the whole paragraph.  The very next sentence literally explains why you're misunderstanding the issue:


--- Quote ---Even if you force the lowpass higher, very little high frequency content is encoded (or rather very little bitrate is allocated due to the sfb21 issue in the MP3 format). 
--- End quote ---

As I said, you can set the lowpass in LAME to whatever you want.  That doesn't mean you're getting much but noise above ~15-16k.  If you're still confused, google sfb21.  Its a well documented flaw in the MP3 format, and there are plenty of people who have explained it better then I.


--- Quote ---
--- Quote from: saratoga ---Its perfectly reasonable that many people using Rockbox would never notice a 22Khz sample rate, even listening to lossless audio.
--- End quote ---

I think virtually nobody could discern anything above even 18khz, which is why many lossy encoders aim at transparency by using a lowpass around those frequencies.   

--- End quote ---

I don't disagree, but I don't think you understood my post.  I was talking about sample rate, not low pass (sample rate must be > 2x lowpass).

Llorean:
Zep: A lot of time when you complain about audio quality, it's something you can only here with high impedence phones or other situations where not everyone notices it. Also, a lot of the developers use their Archoses, or other older players, as their primary listening, possibly even while in the process of testing things on-target for newer devices. So, sound related issues that are faint (and the ticking is something I don't hear, though I have heard the volume clicks) don't get noticed.

Then there's the fact that unless it's something very noticeable to *everyone* it's almost impossible to pin down what causes it. If and when you put up full documentation like the graph you did, it is *incredibly* helpful for finding out what's wrong. In any project it's always asked that you provide as much information about a bug, and a means of reproducing it. So, yeah, you didn't get a response until you measured the problem. But many MANY people have complained about the sound in Rockbox, and then when asked to measure it in the past, have come back with results that show it was identical. So, you'll have to forgive the developers here for taking complaints about sound quality with a grain of salt, but when you're used to people telling you Rockbox sounds like a "bag of shit" you start to want some evidence as to what *exactly* is wrong with the audio, so that not only you have proof it is wrong (if it doesn't show up in your phones) but also so you know where to begin looking for the problem.

lostlogic:
Patience is of the essence here... the I2C driver problem that I believe to cause the clicking on ipod is something that needs fixing for many reasons (all of which are better than a -100dB clicking that is only audible with 100ohm earphones), I'm sure that I or someone will be working on the issue, but it could be a year before it changes.

It would probably make sense to use a headphone amp with your ipod in the meantime as the low impedence of the amp would eliminate the click.

travishayes89:
all i know about the clicking is that if you turn the appropriate option off in the stock firmware you should get no clicking in it, and i never heard a clicking in Rockbox even with a pair of Sony "studio monitors" (i didn't feel like looking for the number).

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