Bad sound in rockbox.... why? please help

[strider]

Hi. I checked the frequency response of my iPod in rmaa.
Equalizer, bass, treble have been disabled.
I got a bad result. AppleOS sounds correct, but RockBox worse.
Why RockBox has hishelf filtering?

I attached graph

[markun]

Which ipod model do you have? Have you disabled the EQ while doing the test (I assume you have, just making sure)

We have had problems with players sounding slightly worse than the original firmware in the past, including some ipods and I believe the iaudio X5 (but can't find the thread for that one)

http://forums.rockbox.org/index.php?topic=9609.45

They had different causes, so I can't tell you what is likely to be wrong.

[saratoga]

Does the headphone output look the same?  Can you post the full RMAA report?

[strider]

my new test)))
i has firmware with  sw eq (24 band).(isanggon)
hw eq is disabled.
changed coupling capacitors.

sound better then in my comp. ))))))))

[soap]

Are you testing with lossy-encoded files?

[strider]

i tested with .wav 16bit 44100Hz

[yapper]

i has firmware with  sw eq (24 band).(isanggon)

What is the performance like with a regular Rockbox build?
What is the performance like with the OF?

[strider]

when I asked the question, I had an old version of rockbox.
in all modern versions of rockbox, the test results are similar to the last of my measurements. that is, flat frequency response.
!!!if the bass and treble will be turned on, then the response will be similar to the first measurement!!!
bass boost and treble boost are not working properly with ipod video

[Llorean]

Are these tests being done on the modified player you mention here: http://forums.rockbox.org/index.php?topic=23264.msg158660#msg158660

[strider]

i heve more then one ipod )))))
and i love expirements

[Llorean]

Please, clarify the exact situation these tests are being done under then. SVN version, any patches applied to the build, etc.

[soap]

I think Llorean asks for a good reason, as we've seen RMA tests before, and high-end rolloff is something new in this hardware with Rockbox.

[strider]

new test.
 isanggon's build [23585] + my own patch disabled eq1&eq5 in wm8758.c + disabled hpout + changed coupling capacitors on line out
standart ----> 500uF.

[AlexP]

The main Rockbox forums are not the place for discussions involving both modified builds and modified hardware.

[soap]

The main Rockbox forums are not the place for discussions involving both modified builds and modified hardware.

After much discussion with AlexP, let me attempt to clarify.

IF you are seeing audio reproduction differences between the Original Firmware and Stock Rockbox we are very interested, regardless of hardware modifications.

IF you are only seeing audio reproduction differences between the Original Firmware and a modified Rockbox build, regardless of how insignificant you view the differences this is not the place.

IF you are seeing non-flat frequency response in Stock Rockbox after a hardware mod, AND have not eliminated the hardware modification as the sole cause of this problem by performing a comparable test in the Original Firmware, this is not the place.