View Single Post
      03-18-2012, 07:31 PM   #35
Lieutenant General
Technic's Avatar

Drives: 2015 320i
Join Date: Apr 2005
Location: Ft Lauderdale, Florida

iTrader: (18)

Originally Posted by taibanl View Post
Any thoughts on pdx vs hd that you feel essential to share? My goals are better fitment (like yours) and power balance amongst my channels. I dont need a ton of more spl headroom other than for sq sake
The jury is still out on the HD amps... two years ago I installed a HD900/5 in a HiFi M3 and it was great. Very straight forward install, sounded great without any processor.

Fast forward two years and a coded EPS-HiFi M3 with two HD600/4 (the one in the picture) and no processing showed some changes in sound quality and compatibility that I'm still trying to understand. For example, although the power output should be the same all the way down to 1.5ohms, a 2 ohms load sounds considerably louder than a 4ohms load. Setting their input level to high sounds slightly better than setting it at low, as it should be (it is HiFi as it was with the HD900/5). Installing a MS-8 in between the CIC and the HD amps have shown similar results, so it is not a matter of balanced inputs.

No XD amp have shown issues like that with HiFi outputs.

Something must have changed in these amps that when the customer contacted JL Audio to ask about these issues their "fix" was to install a Cleansweep.