Low Idle?

["Kappy" <bmkaplan@eniac.seas.upenn.edu>]

In January I purchased a used 89 200.  I love the car and have had many 
wonderful experiences driving it around town.  Recently I've been 
noticing that the car is idling at, what I consider to be a low speed.  
Here is what happens:
	When I first start the car, the engine idles around 1000-1100 
rpm.  When the temperature reaches normal running temperature or above, 
the idle drops down to the 600 rpm area.  The car starts to rattle a bit, 
but I don't have the feeling that it is going to stall out.  Is this the 
normal idle process for this car, or could I have a problem? 

Another thing completely unrelated..
	The Bass from my stereo is killing the back seat passengers.  
Every person I drive around in the back tells me that there is way too 
much bass, even if I turn the bass all the way down.  Lately I've started 
to notice the excessive bass presence.  The car has the Bose 6 speaker 
system, any suggestions how I might reduce this irritation.  

Thanks.

Benjamin Kaplan
1983 Audi 5K ----> 1987 Volvo 760TW -----> 1989 Audi 200TQ