My friend believes that by making the volume of your mp3s higher, you don't
need to play them as loud on your iPod. This, I don't contest. However, he
insists that this saves the battery life. I can't objectively understand why
this would be. Presumably the battery life is drained by processing the file
(which still requires the same effort whatever the sound level), and by
driving the headphones. Surely the battery drain depends on simply the
absolute level at which headphones play a track, not the relative volume of
the file????

BM

"Beacon Mode" <Beacon.Mode@BeaconMode.com> wrote:

Actually, I would assume he's right, except that one also has to
consider whether the MP3s are getting into digital clipping.
Assuming he checks for that, I would predict somewhat longer
battery life when using that trick, since amplification is
relatively constant, apart from the source signal's strength
and the volume/tone settings.

--
Joel Crump

Joel deployed the observation...

Mmm. Sounds like bollocks to me. You still need to drive the headphones at
whatever the output is, irrespective of how amplification you do.

"Beacon Mode" <Beacon.Mode@BeaconMode.com> wrote:

Do you know anything about how amplification works?
It's not that you're completely off base, but in a situation
using batteries, every bit of efficiency can help, and that is where
the advantage would come in.

The digital-to-analog converter generates the source signal based on
the digital volume, which is what your friend is manipulating.
If this is at its highest possible non-clipped level,
the signal fed into the preamp
(in this case, the volume and bass/treble controls of the player)
is as strong as possible, and thus more resistant to
signal degradation and line noise.

Then, with the volume reduced (max volume is simply not changed
from the source) only immediately before amplification
(which is essentially constant), you get the cleanest possible signal.

In fact, I do something similar with my computer (but not altering
my MP3s' digital volume), which I only listen to through my stereo.
I leave all the volume controls in the computer at max,
to avoid signal degradation, and reach over to my receiver's
volume control to adjust the level. Power consumption
isn't even a concern, of course, but signal quality
is noticeably better when the computer's output is at max.

--
Joel Crump

Joel deployed the observation...

Ok. Sounding plausible now... Any idea what kinda effect it may have? I
don't think I can be arsed tweaking my whole collection - it would take
years to process... :-(

"Beacon Mode" <Beacon.Mode@BeaconMode.com> wrote:

It's not something I'd do. I'd just carry plenty of batteries.
The (presumed) effect would add up, though, for heavy users.
I would only alter copies of the original files, though,
and only use them with the portable.

--
Joel Crump

Beacon Mode wrote:

The difference in battery life between your friend's method and normal
is *negligible*, meaning that there basically is none. It is definitely
not a worthwhile practice to adjust the volume of MP3's to save battery
life.
Of much bigger importance to battery life would be the bitrate of your
friends songs, what format they're in (MP3 vs WMA vs Ogg Vorbis vs AAC
(because for different bitrates the hard drive needs to be read more or
less and for different formats different amounts of CPU cycles are
required for decoding)... whether he has the backlight turned on or not,
what state he leaves the iPod, etc....

NeoRenegade <napsterneorenegade@hotmail.com> wrote:

How do you know? What's "negligible" is also a matter of opinion.

--
Joel Crump

"Joel" <joelc999@hotmail.com> wrote in message
news:7g0vk0pclggivuut8m0v0i7btvbko02go0@4ax.com...
Maybe. But he's correct in saying that bitrate and format *are* more
important than the volume at which tracks are played e.g. if I used only
uncompressed wav. files on my Zen Xtra this would use more battery power
than a 128 kbit mp3 file.

BillL

"BillL" <billc1@blueyonder.co.uk> wrote:
I don't recall saying otherwise.

--
Joel Crump

Joel deployed the observation...

Can anyone add any science to this? I'm using typically 192 encoded files -
some higher, some lower but let's take it as an average. I've considered
re-encoding at a lower average (128) just to save some space on my HD - but
will this make a signifcant (and I'm talking 15-30 mins plus) saving to my
battery life on my ipod all other things being equal?