Lack of audio quality on the N900 and useless overhead
 

I'm a bit of a sound-a-holic, being a composer and heavy duty listener, and I've noticed a couple of annoying things about the N900 and it's sound quality.

What I've heard is that the problem has to do with Pulseaudio doing a sample conversion to 48Khz and some software equalizing to make the audio sound better and as worst, automatic limiting to create the so called "wall mix" effect to get higher volume output but killing the dynamics of the track as a side effect (I read that it's a protection so you won't drive too loud volume on the speakers to make them overdrive/break). As much as a normal consumer wouldn't mind these things, they add unnecessary overhead to the N900 cpu and distort the sound in a way that makes me quite annoyed.

As much as I hate to come to the forums asking for someone to make me software that prolly will take days and days to get finished, It's beyond my skillset to code an app that would bypass PA and let me listen to the tracks I've got on the phone as they are (and lets me play tracks managed in a folder/album structure and not just by 1 genre/playlist/etc like the built in one). And I think I can manage to mind the soundvolume without any built in burst protection. Another possibility would be to create a hack on any of the current players to get them bypass PA?

Meanwhile I'll just have to carry another player with me.

Re: Lack of audio quality on the N900 and useless overhead
 

Pulse itself is not limiting anything, player could do, here is the test with mplayer (in extras-testing I think):

# mplayer -ao pulse -af volume=20 /path/to/file
or
# mplayer -ao pulse -softvol -softvol-max=1000 /path/to/file
and use 0 and 9 to increase and decrease volume

Setting volume to high values will distort sound.
Looking at the top output "-ao alsa" still played through a pulseaudio

Links:
http://how-to.wikia.com/wiki/How_to_...maximum_volume
http://www.mplayerhq.hu/DOCS/HTML/en/index.html

Re: Lack of audio quality on the N900 and useless overhead
 

Hmm. I was just couple of days wondering why cpu utilization was so high when listening simple mp3 files. So is it because of this upmixing?
mafw-dbus-wrapper and couple of pulseaudio processes stedy at 15%-25% i tought that playing mp3 would take max. 4-6% of cpu time.

Re: Lack of audio quality on the N900 and useless overhead
 

Yeah there are two factors involved here, the resampleing to 48khz (native sample rate of the audio device) and the eq to prevent speaker damage in pulseaudio.

Pluggin in headphones seems to reduce cpu usage (bypassing the eq)

You can only bypass the resampling by having files that are 48k to begin with.

Re: Lack of audio quality on the N900 and useless overhead
 

Hmm, I did use headphones and still had quite high mafw+2*pulseaudio cpu level for mp3 192kbits stereo 44,1khz.

Re: Lack of audio quality on the N900 and useless overhead
 

Plugging in the headphones definately does not bypass the limiter -effect. I am unsure what you mean by EQ preventing speaker damage, since as far as I understand, equalizing would not do much to prevent that (unless it's a programmed parametric EQ doing the limiting only at required peaking values and boosting overall volume to compensate, instead of a regular compressor/limiter -effect).

In either case, I'd like the player I use to have a GUI, and correct me if I am wrong, but Mplayer doesn't, so it's not that nice for a Mp3-player. I also read that Mplayer is alot heavier.:)

Oh and about the CPU consumption, I've read the bug 5974 talk thorougly, and according to it the oversampling does not affect that much, but something else definately is the cuplrit with PA. Hope someone figures a way to around it.

ps. Easiest way to hear the effect is to listen to and old track which is quite far from a steady dynamic maximum, making the limiter work a bit more. I notice it the best (worst ^^) while listening to some Deep Purple/Pink Floyd/Old Metallica etc. Old poorly mastered tracks. :)

Re: Lack of audio quality on the N900 and useless overhead
 

hello, i've just read your topic... and i wanted to see it by myself.
So here we go.
While using the "top" command in x-term, i started listening to music :
- with the speakers, pulse process went around 22% and 30% of the cpu use
- with headphones, cpu utilisation drops between 7% and 12%. I tested with Senheiser HD650 =P

So what do you think ??

Re: Lack of audio quality on the N900 and useless overhead
 

I think this should be reported as a bug!

The default music player eats wayy too much CPU without providing a steady playback.
Heavy webpages make the playback stutter and unpleasant.

I solved this problem using MediaBox beta but that doesn't make me very happy either as the volume is stuck at ~65% and the performance is not yet quite as it is desired.

Re: Lack of audio quality on the N900 and useless overhead
 

Are U saying that the volume of the N900 isn't at its full capacity ??

Re: Lack of audio quality on the N900 and useless overhead
 

Just in MediaBox, audio can be set to full when you send it to background - I use mediabox because it plays smoother when multitasking.

I say audio is not optimized to play smooth enough AND uses too much CPU.

Re: Lack of audio quality on the N900 and useless overhead
 

i have mediabox, but i didn't managed yet to make it work, maybe i'll try a little bit harder lol

how do you do to set it to full when sending it to background ??

Re: Lack of audio quality on the N900 and useless overhead
 

Call it what you like, that's what it's supposed to be doing without headphones plugged in: filter out or otherwise limit certain frequencies that would damage the speaker. I don't know the details but e.g. Arnim/Pupkin has investigated this quite a lot and was the one i heard describing it.

There does seem to be a lot of PA overhead in general and it would be good to have some answers and options. Coming from a crappier phone music player, N900 audio sounds great to me, but i'm sure it could be better.

Re: Lack of audio quality on the N900 and useless overhead
 

I leave it playing, then I either use load-applet or the button in the interface; the volume button works 100% when the app is backgrounded.

You should reinstall, a new version came out yesterday.

Re: Lack of audio quality on the N900 and useless overhead
 

I really can't agree with you on the soundquality but this is a good topic to discuss about mediaplayers smooth playback which is part of good soundquality.

Re: Lack of audio quality on the N900 and useless overhead
 

Pulse Audio is pretty heavy in general even without adding additional processing to protect the speakers.

I wouldn't mind it so bad myself if we could actually reap the primary benefits of a Pulse Audio system: http://talk.maemo.org/showthread.php?t=36936

Re: Lack of audio quality on the N900 and useless overhead
 

Not having the overhead issue on my N900 through 3.5 jack. 192kb files range from 12 to 14% cpu when adding the two processes up.

Stock player.

Re: Lack of audio quality on the N900 and useless overhead
 

the main thing that annoys me about the additional background processes is that when im browsing the internet it stutters quite often. i really dislike this because the thought of having a powerful processor in my phone is marred because my old tmobile wing (@200 mhz) did similar but not as bad. i hope they resolve this issue soon.

Re: Lack of audio quality on the N900 and useless overhead
 

Maybe somebody could write a script to give the mediaplayer higher priority untill this gets fixed?

Re: Lack of audio quality on the N900 and useless overhead
 

MPlayer can bypass pulse. It's probably not a good idea to do this, as it will block everything else that wants to play sound.

mplayer -ao alsa:device=hw=0.0 file.mp3

Re: Lack of audio quality on the N900 and useless overhead
 

seems like the pr 1.1 update didn't change anything about cpu comsumption when listening to music lol

Re: Lack of audio quality on the N900 and useless overhead
 

Looks fine here. Actually I get one line of cpu usage with music and browser.

And this is posted from N900 :)

Re: Lack of audio quality on the N900 and useless overhead
 

Hi
have you found a solution? the brickwall-limiter effect pisses me off

Re: Lack of audio quality on the N900 and useless overhead
 

don't know what are you thanking me for :)
Does anybodyknow how toget rid of that dynamic range killing?

Re: Lack of audio quality on the N900 and useless overhead
 

Anyone has a solution?

Re: Lack of audio quality on the N900 and useless overhead
 

at what volumes do you listen to your music??
i've never had an issue with the SW limiter using my studio headphones, and believe me, i'd recognize the wall effect. i listen to classical music as well, and i used to record and mix several projects.

anyway, one way to bypass it would be "pasuspender" from the package pulseaudio-utils.
use it like this from xterm: though i don't recommend it. the speakers arent good enough for louder volumes and you WILL damage them, and via headphones it shouldn't be necessary anyhow. also, i have no idea how this would affect the normal phone functions.

edit: to be clear: with pasuspender you effectively shut down pulseaudio, and let mediaplayer talk exclusively and directly to the audio device via alsa. this means no other application will be able to produce sound!

Re: Lack of audio quality on the N900 and useless overhead
 

About 3/4 to 5/6 of bar.... And given some more volume on hifi
The drums which really give beat from a pendrive, via mini jack (double male) don't give any power, are just like ones in 2011's over-compressed albums as "Endgame" by Rise Against (tested on "Spreading the Disease" by Anthrax)

I've been using 2 different cables, two different speaker systems and it stays the same

I wasn't using the internal speakers, but hifi external speakerss
To be clear: the album has 12 dB dynamic range... and sounded better not on n900

is it an CSSU issue?

Re: Lack of audio quality on the N900 and useless overhead
 

I found this in lineout.parameters:

x-maemo.limiter.ul.parameters = hex:f79d5a0030e30500a613440072632e64