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      05-27-2014, 04:42 PM   #13

Drives: '18 M3CP Santorini Blue, X3M40
Join Date: Feb 2013
Location: Valencia, CA

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Originally Posted by nybimmerfan View Post
USB cable connection will produce a much better sound reproduction, much closer if not the same as the source. You have to bear in mind that by using bluetooth, the source audio signals are resampled and reencoded for the bluetooth transmitter and that the encoding will recompress and combine the resulting audio in blocks -- which will usually result in a very short lag from source play. Also there will be some signal attenuation, i.e. if the source has 15Khz signal or higher, the recompressed and transmitted audio may now be gone and only let signals less than 15Khz (usually 8Khz - 12Khz) to go through. There are currently high-end bluetooth systems that are trying to go really hi fidelity which I doubt the M5 music system has. So your best bet is to use a connected source rather than bluetooth. But if your aim is to just listen to music without regard for signal attenuation (i.e. only listen to sound between 8Khz to less than 15Khz) then bluetooth is very convenient.
Great post... basically garbage in, garbage out.

If you're listening to 128KB compressed MP3's, it really doesn't matter the connection type used, as you've already lost so much of the music data - the bluetooth re-encoding that occurs won't strip much more away that's already been stripped. It's still crap in, crap out.

Where people will notice the difference is using a true lossless source (CD's, WAV files or lossless codecs where all the music data is retained) and using a direct digital connection. That's where the B&O system will shine (or the HK system, or any high end audio system). Don't use the bluetooth connection - as nybimmerfan noted, the bluetooth connection is compressing the hell out of your audio files which compromises quality.

I tell people who listen to nothing but 128k or even 256k MP3's just to stick with the stock audio system, use bluetooth, etc. because it doesn't matter at that point. So much of the details of the music have been stripped away.

I *believe* I read somewhere a while back that BMW performs direct digital connections from iPod's, Iphone's, etc. via the dock cradle in the center console or the USB connection. (Dock connection for sure but I would need to do more research on the USB connection.) So a lossless audio file that has never been compressed via the dock cradle connector (and possibly USB) will give you the best possible audio quality, and on a system like the B&O system, you'll be able to hear the difference.

By comparison, Audi's MMI interface does NOT do a direct digital connection via the MMI cable. It's one of the biggest annoyances I have with Audi's MMI system - you can spend $7,000 on their B&O reference speaker system and unless you are listening to a CD or a lossless audio file via the SD card slot, you aren't getting a direct digital connection. *Any* Apple device connected to the MMI cable is getting the digital audio converted to analog, sent to the B&O amp and then converted again from analog to digital. It's totally pointless and neuters the audio quality. They are apparently "fixing" this with their latest gen MMI/MOST interface but I haven't confirmed that yet. This is something that BMW does right.

Hopefully one of these days the iTunes store will offer a lossless/uncompressed file download option, because it's frustrating that everything you download from there has been compressed already. Most people don't mind the lost data because the files sound pretty good as-is, but if you hear the original uncompressed version, there are times the difference is striking. Techno/trance/dance music is where the compression really takes a toll on the original source.

Last edited by TonySCV; 05-27-2014 at 04:51 PM.