BMWSTL

Question for those familiar with iPod or other players and attaining the best audio quality from music transferred from CD's (or downloaded).

When I transfer songs from my CD's into iTunes and then onto my iPod for use with the new USB interface, what settings are best for achieving maximum audio quality and functionality with the USB interface?

According to BMW's technical information, the new USB interface has the following technical specs and limitations:

I've read that uncompressed 16/44 .wav files provide the best audio quailty, but they are apparently not supported in the playlist through the USB interface. A compression bit rate greater than 256 kbps seems desirable, but anything greater than that doesn't seem to be supported by the USB interface. What format (.mp3, .acc or other) and at what bit rate (256, 192, other) is recommended to get the best possible audio quality with maximum functionality through the USB interface? And, can you hear the difference between uncompressed .wav files and the "least compressed possible" files with the Logic7 system?

Thanks,

Lou

BMWSTL

I may be answereing my own question, but here goes.

After doing some research and reading the USB technical information, it appears the best quality available is when the files are least compressed, and that a "lossy" file transfer protocol (including .aac and .mp3) should be avoided. Unfortunately, the USB interface does not support some of those protocols (such as Apple Lossless and AAIF), and although .wav files are uncompressed and can be played through the USB interface, .wav files won't show up in the playlist (plus they are huge and will eat up storage space quickly). Although a bit rate in excess of 256 kbps will have less loss in any file compression scheme, the USB doesn't support a higher bit rate.

Other than bagging the USB interface and an iPod and instead use the source CD's, the best answer seems to be to use Apple's .aac encoding at 256 kbps. Using that scheme will allow for minimum compression of the files while at the same time maximizing the usability of the USB interface.

Anybody have any comments?

Thanks,

Lou

Hopco

Hey BMWSTL

I cannot hear the difference between CDs played and the same encoded at 192kb/s AAC on my home music system.

Of course I certainly do not claim to have Golden Ears - having done a lot of duck shooting in St Charles county and dove shooting at Champs Farm under the old Lambert StL Airport many years ago. The stress to my ears has been compounded by 6 years in Naval Aviation and three score plus years on the planet.

Thus I am quite happy with my iPod setup in my 530xiT. Also remember, it is one thing to have perfection in a home listening room where background noises may be 35-to-40 db and another in a BMW where the cruising noise level may be 50-to-60 db.

Regards

enelrojo

Maybe 75 to 85 db with runflats.

GarryF

Yeah, this has been discussed near on 10 years now. 192kb/s seems to be the max for mp3, any higher and most people won't spot the difference in proper double blind tests. When I first started ripping CD's back in 2000 I think I used 320kb/s, nowadays I just use 192kb/s. Also what you use to create the mp3 can affect quality, google for EAC (exact audio copy)

I think a lot of people compare their CD player at home to their mp3 player and blame compression when it's more likely the player.

Why don't you put 5 different versions of the same song on the player, and then get someone in the back seat to randomly select them and see if you can tell the difference with the engine on

BMWSTL

Excellent suggestion!

Lou