I just replaced my stock radio on my 99 a4 with an alpine hu. The radio seems to be distorted.
How do i get better reception, antenna adapter?

 

Yes, you'll need an antenna adapter, and if I remember correctly, it has to be amplified.

 

nah doesnt HAVE to be ampped just make sure you got the right antenna adapter
if you look up metra the part numbers are 40vw10 and 40vw53, im not sure what one you need but it will be one of those. i htink if u have bose or monsoon system or whatever u need the 53 and the 10 is for basic radios.

 

when i hookep up my h/u there was no sound coming from the rear speaker so i had to run connect the rear speakers straight to my h/u so i assume that i have the system with the amp, is that safe to assume so?

 

My amp was in the trunk hanging from the top just under the driver's side rear deck speaker. Its about a foot long, 6 inches wide...

 

Yes the Antenna adapter has to be amplified only if you want the AM to work.