Rockbox mail archive
Subject: Re: High kbps/Low kbps power consumption
From: Neon John (johngd_at_bellsouth.net)
On Thu, 5 Jun 2003 13:08:28 -0400 (EDT), <stevem_at_gator.net> wrote:
>As a followup to my previous email, I've noticed that my Jukebox recorder
>20 has trouble with 320kbps-formatted MP3 music files when the battery
>level gets down to around 55 percent or less. Is this a known issue with
>the Jukebox? I didn't see much about it in the bug reporting list.
>I loaded the daily build ajz from June 4th, but I'm still having this
>problem. I can hear the hard drive being accessed, then, afer a while, the
>music will cut in again. It drops out intermittently.
No, not a bug. Just an effect of running the thing at the edge of its
performance envelope. Contemplate how much data the thing has to move to
handle that bitrate and how much processing it takes and how much power that
requires. Given that there is a fixed amount of RAM, the higher the bitrate
the more often the drive runs. More power required. You're simply
overwhelming the unit and with no material gain in sound quality.
>Anyway, seeing this happen is what prompted my previous question. Is it
>best not to play music on the recorder formatted above 128 kbps?
I have very good ears and I can't hear the difference between the original CD
and 192kbps even on my mid-level home system playing directly from the
computer. I certainly can't hear the difference once the sound goes through
the Archos' audio output circuit and then through headphones, even my
PortaPros. It is a waste of space and processing power to put anything above
128kbps on the Archos, unless perhaps you're using the digital out to a high
I store all my rips at 192kbps on my computer. I downsample to 128kbps for
the Archos using CDex and LAME. On this 2 gig machine the process is quite
rapid. Since I have the disc space I simply maintain two file trees, one for
the original rips and one for the archos.
If you're using the thing primarily in non-optimal listening environments such
as a noisy office, the car, jogging and such, you might try going even lower.
There is a tradeoff between bit rate and battery life. You might find the
lower sampling rate adequate for those environments.
I downsample my audio books to 32kbps. there is a little distortion but it's
acceptable, certainly better than, say, a mobile radio. My FM can suck in
whole chapters at once, spinning the hard drive only every 15-20 minutes or
so. That is how I get better than 14 hours' life out of a charge.
Best thing to do is simply experiment some. Downsample to various rates and
do some listening tests. When you find something you like, check the battery
life. You'll be pleasantly surprised.
>> Hi folks.
>> I have an Archos recorder 20. Does playing a 320 kbps recording pull
>> more power from the batteries than playing a 64 kbps recording?
John De Armond
Cleveland, Occupied TN
Page was last modified "Jan 10 2012" The Rockbox Crew