I have a massive libray of music, as my wife and I rip every cd we buy onto our music server. We use flac as that gives us a complete lossless copy of the original CD. However the files are giant, and are not suitable for loading on your portable audio devices. I use a program called dBpoweramp for ripping and I do a bulk transcode of the entire library down into a smaller format.
Interestingly I had my ears tested lately and happily they are still fine. But I have lost some of the upper end of my hearing as all of us do (unfortunately!) as we age. I can't hear the dog whistles any more. ;-)
Here is a fun site to test the upper range of your hearing if you are curious:
http://www.noiseaddicts.com/2009/03/can-you-hear-this-hearing-test/
At any rate, I decided it was time to re-evaluate how low I transcode my flac files to mp3. "Back in the day" mp3 files used to all be encoded at constant rate... and those tended to really be poor quality sound. It was pretty typical for people to rip mp3 at 320kbps to maintain good sound. These days with a quality encoder (lame) using a variable bit rate you can get pretty fair quality sound at relatively low bit rates.
There is a fun article on whether high bit rates are worth the space here:
www.maximumpc.com/article/do_higher_mp3_bit_rates_pay_off
That article really convinced me to try a lower bit rate.
Since our library is massive, and I hoped to get as much as possible of it onto our portable media, I decided to go for the lowest bit rate I could hope would still be adequate. Using lame (built into dBpoweramp) I decided to try the default setting:
-v4
that means a target bit rate of around 160 bps.
Googling around, that seemed to be a good number. Interestingly, back in the day of CBR, I wouldn't have considered such a low bit rate. But with VBR it's pretty good.
At any rate, once I ran the transcode overnight, I ended up with a library of around 40GB. Still big, but I can fit most of it on a 32GB microSD.
And look at this cool little gadget I found:
Its a cool little USB microSD card reader that holds the microSD right in the connector! What great industrial design. Under $10 on Amazon.
So cool, I now have about 6000 tracks easily accessible on the car stereo! Since I arrange my music in folders by genre/artist/album/track its pretty easy to navigate through the music with the stock head unit.