I recently bought a pioneer dh7300(???the one with dolphins etc) and istalled it in my 89 k5 blazer.

Well the wierd part is, when im driving, and the volume is set to a constant setting, playing either a CD OR the radio(doesn't matter), The sounds loudness will go up.....and down. considerably to. it will get so quite sometimes.

Its almost seems related to RPM, although probally just a coincidence.
Example: Driving down a road and a light turns red....i stop and the volume goes down. i go again and after 30 sec it will go back up.

Seems like RPM right?

Example 2: Driving 70mph on the freeway cruise on...its will sometimes be totally stable but in most cases will go up and down on maybe a 30 sec cylce.

Its so anoying, the voltage gage always reads a constant so i dont think the cars voltage is varing to much, even though the shouldn't mattar at all

Help??

 

I don't know if an '89 Blazer has this feature, but some vehicles do have a speed related volume control. I don't know how you'd defeat it if the Blazer does have it. If you have the instructions that came with the deck, look through them and see if there is anything about speed related volume control.

 

Never seen this problem with radios but some amps cut back power when they get hot.