PDA

View Full Version : MP3 quality poor due to low volume levels, notcompression.



Jason
2003-12-31, 22:35
MP3gain does not FIX clipping, MP3gain NORMALIZES your audio output levels.
It sounds like you are saying that you are reporting the problem of your
iPod and Squeeze not providing the same output level as other audio
components you own. This should not be a surprise to you. Output levels on
electronics equipment varies quite a bit from one device to the next.

Do yourself a favor. Go to radio shack and purchase a cheap SPL (sound
pressure level meter). Find out what the dB level is when you are listening
to your CD player or other device at a comfortable volume level. Rip a wav
from the CD with NO NORMALIZATION from EAC or from mp3gain. Play this wav
file through the squeezebox via the digital output. Adjust the volume level
on your amplifier to the same dB level on the SPL meter. Although you might
be turning the amplifier up a bit more, there should not be any additional
noticeable distortion.

If there IS distortion at this slightly higher output level from your
amplifier (to achieve the same volume level as the CD player) then I can
assure you that your amplifier is being overdriven and you need a better
(not necessarily more powerful) amplifier.

-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of Simon Turner
Sent: Wednesday, December 31, 2003 7:53 PM
To: Slim Devices Discussion
Subject: [slim] MP3 quality poor due to low volume levels,
notcompression.

Jason.. the immediate goal is to avoid clipping (distortion), not to
"normalise" the whole collection.
I am not "normalising", as I understand this can irreversably change the MP3
files. Replay Gain does not "normalise". I have learnt this from the
Hydrogen Audio, MP3Gain and Replay Gain web sites.
The problem seems to be that when files have had clipping removed by MP3Gain
the volume level is reduced and is then lower than hardware devices like the
iPod and the Squeezebox are designed for. So the output thses devices then
provide is not sufficient to properly drive the input of many hifi
amplifiers. This results in a thin and weedy sound. And the only way to get
any volume is to crank up the volume on the hifi amp much more than one
would for the other peripheral devices (CD, Tuner etc).

Buying a more powerful amplifier will not change anything, just give me a
louder weedy sound.

I am just looking for a reason why, in my case, the iPod and the Squeezebox
do not seem to provide as high a level input to my hifi amplifier as all my
other (more standard) devices.

I am perplexed that there are not many others who have the same problem and
of course this worries me. I would be quite interested if the person who
said something like "I can't see how ripping through EAC could introduce
clipping" would run his ripped files through MP3Gain
(http://mp3gain.sourceforge.net) and read the programs help file.

Perhaps I ought to disregard MP3gain (Replay Gain) and all that is
recommended at Hydrogen Audio and just increase the gain on my files to
levels above clipping... but... although I cannot hear ANY distortion due to
clipping when MY MP3 files are played through my computer the distortion is
very obvious when the same files are played on my iPod.

My post is not meant as a criticism of the Slim devices at all. I am just
looking for help.

Simon
Brighton UK.




-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com]On Behalf Of Jason
Sent: 31 December 2003 23:32
To: 'Slim Devices Discussion'
Subject: [slim] MP3 quality poor due to low volume levels,
notcompression.


What is the whole goal here? I just rip/encode with EAC and LAME. I have a
few albums that have slightly lower volume than others but I don't see the
need to normalize my whole collection down to 89db just to prevent having to
adjust the volume knob once in a while.

So again, what is the goal here? If you are doing normalization there are
lots of additional factors that can be screwing things up for you.

If you are saying that the squeeze is not loud enough once everything is
normalized, welcome to the wonderful world of normalization, you can always
buy a more powerful amplifier.

-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of Jason Holtzapple
Sent: Wednesday, December 31, 2003 2:19 PM
To: Slim Devices Discussion
Subject: [slim] MP3 quality poor due to low volume levels,
notcompression.

--- Caleb Epstein <cae (AT) bklyn (DOT) org> wrote:
> On Wed, Dec 31, 2003 at 08:40:20PM -0000, Simon Turner wrote:
>
> > Hi Jason, Volume level is set to max. I use Constant Gain as it
> > enables me to be sure I have got the cd I am ripping to the highest
> > volume without icurring clipping in any individual track, whilst
> > still retaining the different volume levels between tracks. Usually
> > i find that just going one step down (i.e. -1.5db) gets rid of any
> > clipping introduced in the ripping process. I'm not too sure if
> > album gain does exactly this.
>
> How could ripping a CD introduce clipping? You're just
> extracting the WAV data off of the disc. If you have a decent
> drive or use the right software, its a perfect copy.

Probably not the ripping, but the encoding. I have plenty of
EAC/LAME --alt-preset standard encodes that are clipped
'out of the box' according to mp3gain.

> I expect album gain normalizes an entire disc as a single
> unit, so the highest peak of the entire album is at 0db. You
> seem to be normalizing on a per-track basis, so the highest
> peak of every track is at 0db.

It might help if Simon tells us what he's trying to
accomplish: a similar volume throughout his collection
or simply trying to reduce clipping.

--Jason

__________________________________
Do you Yahoo!?
Find out what made the Top Yahoo! Searches of 2003
http://search.yahoo.com/top2003