Rockbox Technical Forums

Rockbox General => Rockbox General Discussion => Topic started by: showcaser on May 15, 2007, 11:09:49 AM

Title: Quiet e200
Post by: showcaser on May 15, 2007, 11:09:49 AM
Hi All,

this is my first post and i'd like to start by saying thanks to all those who work on rockbox.

I recently installed rockbox on my e280 and am having some problems with the sound/volume. At first I thought there was a sound quality problem with rockbox but after a little reading realized that the distortion I was experiencing was because the volume was typically up near the 6db maximum. The problem is that unless i'm somewhere up near 0db or more the volume isn't reasonable. I installed rockbox on my friends nano and with the same song his -15db is comparable to my 0db+. I'm not having any volume issues when running the sansa firmware and playing with the equalizers so far hasn't helped.

Is anyone familiar with this issue? Have I missed a setting somewhere?

I should also mention that i've mainly used rockbox on speakers and not headphones, but again, no problems with original firmware or rockbox on the nano for that matter.

Aside from this I think rockbox is awesome and look forward to continued development.
Title: Re: Quiet e200
Post by: Llorean on May 15, 2007, 11:18:38 AM
Rockbox on Sansa is still in a very early state, and there are a lot of audio related kinks still in need of straightening out.
Title: Re: Quiet e200
Post by: Vortex on May 15, 2007, 03:09:25 PM
I have the same problem on my Sansa. The volume is very faint, especially when using EQ settings that require you to use precut (which is neccessary, because rockbox doesn't sound very good with standard EQ settings, at least compared to the original firmware).

Another problem that I came across, is that the sound on rockbox gets distorted when you turn up the volume too high (in other words: past 0dB) even though it is still not that loud. The original firmware can play music at a much higher volume without any distortion.

There is also a third issue with audio playback, which is kind of hard to describe: When the volume is set to a high level and I play a song that has many sudden volume peaks (e.g. a loud base drum or similar) the volume starts to fade in and out (it fades out on the loud passages and then fades in again; it sound very weird). It sounds like a recording made with a cheap microphone with auto-adjustment of the recording volume, if you get what I mean... ;)
Title: Re: Quiet e200
Post by: X86 on May 16, 2007, 07:43:46 PM
as it said Llorean rockbox is in very early stage of development,but that sounds weird I don't have that experience with mine,anyway just wait,I have no troubles with mine,just have to wait,and Llorean you and all the developers are doing a great job
Title: Re: Quiet e200
Post by: Vortex on May 17, 2007, 06:41:27 AM
Quote
Llorean you and all the developers are doing a great job


I second that. Sorry if my above post sounded like a complaint. :)
Title: Re: Quiet e200
Post by: showcaser on May 17, 2007, 04:50:32 PM
Likewise, definitely not a complaint. I'm very impressed and thankful of the work the developers have put in.
Title: Re: Quiet e200
Post by: major_works on May 17, 2007, 10:35:00 PM
Fixes were committed to SVN today that significantly improve audio volume and quality on the e200. You might want to update and check it out.
Title: Re: Quiet e200
Post by: showcaser on May 18, 2007, 04:07:06 PM

Fixes were committed to SVN today that significantly improve audio volume and quality on the e200. You might want to update and check it out.


Indeed, I updated today and there is a huge difference!!

Thank you
Title: Re: Quiet e200
Post by: RowaN on May 22, 2007, 01:55:05 PM
With the volume going up to 6, does that mean I can theoretically put the bass up to 6 too, without experiencing clipping?

Todays build is sounding very nice.  =]
Title: Re: Quiet e200
Post by: Vortex on May 22, 2007, 02:07:08 PM
It should not clip as long as the volume is set to 0 or lower. If you raise it to 6 it will most likely clip. However, you can specify a precut for the equalizer to prevent clipping. That way you will be able to raise the bass in any way you like. ;)
Title: Re: Quiet e200
Post by: nls on May 22, 2007, 02:10:49 PM
Yes it you turn up bass, treble or any of the eq bands, you have to make sure that volume+precut+boost+eq >= 0dB to be sure to not add any clipping
Title: Re: Quiet e200
Post by: RowaN on May 22, 2007, 02:27:18 PM
Hmm sounds like theres a bit of maths involved here. I dont really understand what precut, and boost are, despite reading the manual (http://download.rockbox.org/manual/rockbox-sansae200/rockbox-buildch6.html#x9-920006). I have the EQ turned off - can someone give an example of how high I can turn the volume & bass without clipping?
Title: Re: Quiet e200
Post by: saratoga on May 22, 2007, 03:39:32 PM

Hmm sounds like theres a bit of maths involved here. I dont really understand what precut, and boost are, despite reading the manual (http://download.rockbox.org/manual/rockbox-sansae200/rockbox-buildch6.html#x9-920006). I have the EQ turned off - can someone give an example of how high I can turn the volume & bass without clipping?



If the final gain (volume control + EQ+ ...) for any frequency is positive, you will get clipping.  Thats basically all you need to know.
Title: Re: Quiet e200
Post by: nls on May 22, 2007, 06:27:42 PM
so for example if you just use volume and bass, if you turn the bass up 6dB you should keep volume at -6dB or lower to avoid clipping
Title: Re: Quiet e200
Post by: RowaN on May 23, 2007, 03:14:01 AM
Thanks guys. How does having replaygain enabled (with replaygain's prevent clipping mode also enabled) effect these calculations?