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H140 Bad sound on Optical out!

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nuss75:

Hi all!


I recently tried my H140 as a transport to a Benchmark Dac1 supposedly one of the best out there.  ;)

I used Rockbox a cheap optical adapter from mini to TosLink and .FLAC files.
The player sounded like it had no dynamic in heights and lows and the whole spectrum was in the mids. ???

Compared to a TosLink connected (without the adapter) CD player for 180$ it came last. The CD player rocked the pants of the Iriver.
Why could this happen?

I tried many different FLAC files from different persons always the same.

I would be happy to hear your thoughts on this :).

pabouk:
Could you please send more information about the .flac files?
(sample rate, bits per sample, channels)

AFAIK Rockbox cannot play files with the sample rate higher than 44.1 kHz directly without resampling at the moment. The resampler is not the best one unfortunately although it should not cause such a big problem.

Llorean:
CDs are 44.1 kHz. If you rip a flac from a CD, and play it through the optical out to a DAC, if the rip is perfect, you will get the *exact* same audio that you get from a CD player with optical out.

Because it is digital output, the fault lies with the file, not the hardware, unless either there's a bug in Rockbox right now, or you had the equalizer, crossfeed, or some other sound-coloring feature enabled.

nuss75:
Hi!

Thanks for the input Llorean.

Soo that could be the case.

I thought that sound coloring couldn’t happen. Like that the output couldn’t  get higher volume from me sliding up the volume.
I thought it went unfiltered to the dac.

I think I double checked that my eq vasnt on. Is there other filters than eq and cross feed out there that could have effected my DAP performance.
And I don’t know what quality the .FLAC files are. :-\

pabouk:

--- Quote from: nuss75 on October 27, 2006, 11:57:04 AM ---I thought that sound coloring couldn’t happen. Like that the output couldn’t  get higher volume from me sliding up the volume.
I thought it went unfiltered to the dac.
I think I double checked that my eq vasnt on. Is there other filters than eq and cross feed out there that could have effected my DAP performance.

--- End quote ---
The parametric equalizer and the cross feed are the only digital filters in Rockbox currently. Only the digital filters can affect the digital output.

Other settings like volume control and the two band equalizer are implemented as analog filters directly in the hardware (after the internal DAC). They cannot have an impact on the digital output because it transmits digital signal taken before reaching the internal DAC.


--- Quote from: nuss75 on October 27, 2006, 11:57:04 AM ---And I don’t know what quality the .FLAC files are. :-\

--- End quote ---
In such a case we cannot say anything about the problem :-\

I would recommend you either
- creating .FLAC or .WAV files of a known quality
- or testing the .FLAC files in a different player (for example on a PC with digital output).

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