Real Line Out with ROCKBOX

[klypso]

Hi,
I was listening to Dr chesky's music and wtf i heard so much noise in the sound
So i tried to play the same music in the Ipod firmware and what happened ?
No noise, the signal was perfect with my dac amp (leckerton)

So, why i haven't the same signal while using RB ?
Because now i have to convert all my DB in alac .. so sick

If you can improve this, everybody will be grateful
(BTW, i'm using a 5gen ipod classic)
Thanks

[saratoga]

Post a link to the file in question.

[torne]

Did you have the volume turned up above 0dB?

[klypso]

Ican't post the file but it's in 24 bits and 192khz so it's possibly why i have some noise, i've the same problem with my portable computer
The volume can be adjusted, if i put it to 0 i have no sound, but it works like a preamp i think, in neutron mp on android when i active the preamp option i have the same thing, i can change the volume during 30 db (on the ipod) and then the volume became "stable"

I don't have these problems when i'm on the original Fw

[torne]

0dB is line level; if you set it higher than that then you are boosting the volume up louder in the digital domain, possibly introducing clipping. If you don't get any sound with the volume on 0dB then there's a problem..

Rockbox outputs only at 44.1kHz 16-bit, so anything higher than that has to be resampled, which takes more CPU time and may make it sound worse. The iPod Video doesn't have a very powerful CPU so it doesn't take too much DSP to push it over the limit and have it unable to keep up.

[saratoga]

Ican't post the file

Then I can't help you. 

[klypso]

Ok ok, but can you explain me why i can adjust the volume with the ipod ? Normaly when i use the line out, in my computer or with my cellphone (galaxy note 2) i can only adjust the volume in the dac/amp, can you explain why ?

[saratoga]

Ok ok, but can you explain me why i can adjust the volume with the ipod ?

At very low volume settings, the line out and headphone out share a volume mixer on the ipod 5g.  Above ~-60dB, that doesn't happen, so if you want fixed line out, dont' set the volume extremely low.

[klypso]

Ok, thanks for the explanation