[taibanl]

Originally Posted by Technic

If the Professional Radio/iDrive unit was coded to HiFi as part of the Alpine Retrofit installation then the obvious answer is that the rear speakers are being driven by a low level signal. That's what HiFi means = low level outputs.

Otherwise, this is normal behavior: the front/underseat woofers are powered by some 80W per channel by the Alpine amp while the rear speakers are powered by the internal HU/iDrive IC amp with 15W-25W per channel.

Guys, can some of you download the free JL Audio Tools app and do a rudimentary SPL meter test faded full front and full rear (with some kind of constant signal like pink noise)

Originally Posted by Exwoodchuck

No, I don't have it solved. It has to do with the volume levels that are set when 676 is added to your VO as part of the coding for the Alpine Retrofit.

A few of us are trying to crack the code, and I'm pursuing this through contacts at BMWNA. It's rendered my Bluetooth connection to the car pretty much useless, so I'm a little grumpy about it.

Why does it render your bluetooth useless?

Originally Posted by Catalyst Group

Makes sense... but again, what is the point of upgrading one component when another one will stop working?

If someone is brave, they could crack open the amp and try to switch the jumpers from high level to low level and see how this effects PDC and bluetooth (my thoughts are PDC worse, bluetooth better)