HOW TO DETERMINE WHICH AUDIO SYSTEM YOUR VEHICLE IS EQUIPPED WITH
More info about determining the audio system in your BMW
This is the "standard" audio system offered in BMWs in the U.S. (except model years 2010 and 2011 when "Base" was standard equipment) and an optional upgrade for BMWs outside the U.S.
If you live in the U.S. and do not have one of BMW's "Premium" audio system offerings or a 2010 or 2011 model year BMW, you have this audio system.
Although exact specifics vary from vehicle to vehicle, this audio system is generally characterized by 10 total speakers and an external amplifier, no user adjustable "DSP" processing or equalizer settings, and "average" overall performance.
Harman Kardon / Premium (Top Hi-Fi)
The is the premium audio system type for a large number of BMW vehicle years and models, typically characterized by a more powerful amplifier and more total number of speakers. Look for logos that say "harman / kardon" on your speaker / tweeter grilles. If you see that logo, you have the "harman / kardon" system.