mp3 - Bitrates

[ShiroiNeko]

Why does Jpod101 use so many different bitrates for mp3's ?

Checking on recent downloads, I noticed that the bitrate is anywhere between 80 and 320, with the majority of them at over 192.

I would have thought that a bitrate of 128 would have provided more than enough sound quality for what are mainly vocal recordings - and also help both Jpod101 and subscribers to save some storage space.

[webbug]

The current size of all of JapanesePod101.com mp3 releases is just over 9 gigabytes. This is including all bonus audio, review audio, dialog audio, etc. That's 3 years worth of releases and it can still fit easily on a 4th generation ipod nano.
Most, if not all, of the JapanesePod101.com mp3s are encoded at a variable bit rate (VBR). What you are looking at are most likely the average bitrates for the mp3s. When a mp3 is encoded with a VBR, the mp3 is allowed to use a higher bitrate for periods of high complexity, and a lower bitrate for periods of low complexity within the mp3. This means that all of the data stored in the mp3 files is necessary to maintain a certain level of sound fidelity. If the files were made smaller, they would inevitably lose sound quality.
What level of sound quality is acceptable is a matter of opinion. Everyone hears differently and thus, everyone has a different opinion on this matter.
It is true that voice recordings are typically made at a much lower bitrate than other recordings. However, it is also true that those voice recordings are typically used to provide information in a language the listener is already fluent in.
By providing high quality mp3 files JapanesePod101.com can assure their listeners that all of the nuances of the Japanese language will be preserved. This allows the listener to hear proper intonation, inflection, accent, and other subtle cues that may be lost were the recording quality to be lowered.

[Jason]

It is true that voice recordings are typically made at a much lower bitrate than other recordings. However, it is also true that those voice recordings are typically used to provide information in a language the listener is already fluent in.
By providing high quality mp3 files JapanesePod101.com can assure their listeners that all of the nuances of the Japanese language will be preserved. This allows the listener to hear proper intonation, inflection, accent, and other subtle cues that may be lost were the recording quality to be lowered.

Not to mention the podcasts often contain music and other sounds that wouldn't be reproduced well at lower bitrates. Besides, storage cost per GB is ridiculously cheap nowadays.