CD Stacker query

[Jazzbass 1]

I have a 1996 car and my stacker won't read mp3's.

Would a changer from a newer car read them, or is this more a function of the whole radio?

[Carl 3]

One would suspect that it is solely the head unit that is responsible for controlling the stacker and you'd have to upgrade the head unit to play mp3's

[Jazzbass 1]

Ok, thanks, Carl.

[bravo 34]

Talking out your arse Carl! The cd changer is the device that decodes the information before sending to the headunit - you need an mp3 capable changer. I don't know what year bmw supports mp3 in the changer, but aftermarket mp3 capable cd changers start at a little under $300.

[Jazzbass 1]

OK - confused now.

Where's Jochen?

[Carl 3]

Talking out your arse Carl! The cd changer is the device that decodes the information before sending to the headunit - you need an mp3 capable changer. I don't know what year bmw supports mp3 in the changer, but aftermarket mp3 capable cd changers start at a little under $300.

Damn misinformation, got it the wrong way around again

[bravo 34]

Idiots! Gosh!

The signal from the CD/mp3 changer is an audio stream - already decoded by the cd changer - not a raw data stream directly off the CD - have a look at your retailer - some CD changers are mp3 capable and others aren't - wonder why that is???

And if you can tell the difference between CD and high-bit-rate mp3 over factory bmw speakers with the usual road noise then you have ears like the chick on the JVC ad.

Unless you have a competition level SQL setup or have very low-bit-rate mp3 files, you won't be able to tell the difference - I'll stake a beer on it.

Edited May 26, 2006 by bravomikewhiskey

[jochen 4]

Hello, I heard my name mentioned :-)

The older BMW CD changers were not MP3 capable - who had heard of MP3 in 1996 anyway?

The later models from around 2003 or 2004 have MP3 capable CD changers, but these ones are controlled by the I-Bus from the radio.

Most 1996 radios didn't have I-Bus control. Or if they do, it's not cabled, and you have to run an I-Bus wire.

Anyway, the MP3 capable BMW changers sell for a premium 2nd hand in Germany - guess why? :-)

Another option is to fit a Sony MP3 capable CD changer, controled from your standard BMW radio. You need an interface unit between the native BMW CD changer cable and the Sony CD control cable. Such interfaces sell for 50 to 100 Euros in Europe.

Here's one on special:

http://cgi.ebay.de/CD-Wechsler-Adapter-BMW...1QQcmdZViewItem

Note that it says it's for 98' onwards, which means this adapter uses the I-Bus control signal.

If you don't like Sony, you can fit Alpine, or Pioneer etc, with the appropriate adapter, so the headunit is fooled into thinking it has a native BMW changer connected.

There you go. 2 ways to do it, the adapter is probably the best way, depending on the exact headunit you have

If you want more details, PM me

Jochen (the BMW Radio Guy)

[Neal 513]

I have a 1996 car and my stacker won't read mp3's.

Would a changer from a newer car read them, or is this more a function of the whole radio?

Interesting thread

MP3 Files have two parts within the data file.

Firstly the bits have an encoded audio stream , which has been sampled data rates between 24 bits / sec to 320 bits , The higher the bit rate, the lower compression of the orginal audio track. (Read closer quality to the orginal track)

The second part of the mp3 file contains data , such as track name , group name etc.

The function of the head unit in an MP3 system is to decifer the data part of the file system of an bunch of MP3 which has track name etc. The Headunit will also extract the audio stream for the data file so you can hear it .

Mp3 boot changers normaly do the following.

Extract the audio out of the MP3 file and pass it to the head unit via the RCA audio leads.

Extact the Mp3 Data information (ID3 tag) and send it down the "Bus" part of the stacker cable to the head unit so it can display the track. Or the Headunit will send instructions down the data bus to tell the bootchanger which track to play.

In regards to your 1996 headunit / stacker neither can either play or control MP3 encloded CD's. It's not a case of adding a Mp3 boot changer to the headunit as it won't be to control what track to play etc. The only way to get a Mp3 stacker to work with the unit is to get one with a remote control / display unit and connect that to the head unit .

Personally if I was going down the Mp3 track , I'd replace the headunit with something that can connect and control an Ipod. With 60 gig you can sample the CD's with Wav files and have no compression on the audio tracks. Or fit 400-600 Cd's on it in Mp3 format

In terms of Mp3 Verse CD's in a car. If the sampling rate is 128k or above , I tend to agree with bravomikewhiskey with most factory car systems. The difference is so slight due to the resolution of the factory head units / speaker (HK pack included) that most people won't tell the difference.

But then again , why limit your music to 10 or 11 CD's when you can carry your entire collection.

[jochen 4]

I beg to differ

You CAN control the MP3 CD changer from the standard BMW Headunit

You won't get track names and titles on the screen of the radio, because the radio won't support that function

But it will play the tracks on the MP3 CD.

Exactly how the MP3 CD changer plays the tracks - ie: which way it follows the directory tree on the CD - varies between manufacturers of the changer.

Most of them sequentially play the tracks and recurse through the directories as they are found.

But it does work, and you can fast-forward and rewind, and move from track to track via the radio controls.

Exactly the same as if the MP3 was a standard CD.

The audio is, as you suggest, passed on as analogue audio to the head unit. The MP3 decoding from digital to analogue all occurs within the CD changer.

Cheers, Jochen

[westy 614]

Does that answer your question Jazzbass?

[Jazzbass 1]

Yes, it seems like just too much pissing around for me to worry about it.

Truth is I don't actually need it, it just sounded like a cool thing to have if it was easily available.

Most times I don't even have the stereo on while I drive. When I listen to music it is almost always on my PC, so mp3 is my usual way of hearing music.

As far as reproduction quality goes, yes I can hear a clear difference between CD and mp3s at home, but I agree, in the car, with road noise, talking etc, the difference is harder to hear and really, the quality isn't important to me.

The standard BMW 10 speaker stereo is certainly good enough for my ears.

Thanks, all.

:bowdown: