Myself and a friend just completed an install based on ALOT of reading and research of this forum and others, of a Rockford Fosgate PBR300x2 amp and Infinity Kappa 6.5 coaxial speakers in my 2010 Ultra Limited and his 2005 Ultra Classic. The only differences are I have the Harmon Kardon head unit and he has the older stock Harley head unit (not sure what it is, but it isn't a HK). Upon final inspections and powering up, we set gains by injecting a 1k tone @ 0db and observed the sine wave on an O'scope. We brought the volume up on our respective head units to just under clipping (which on the HK was one bar past the E in the word Volume...) and then set the amplifier gains the same way. Both amps clipped at 6 so backed them off to 5 and called it good. This is where my question comes in.....He has considerable "lower end" volume at only 1 bar, whereas mine has to be above 3 bars to barely hear it. If he sets his volume on on the first bar and I do the same, his system is much louder. I will catch up to him further up the scale but I do not always want to ride with the volume at half scale or higher just to be able to hear the radio.

Has anyone else experienced this?

I put RCA male plugs on a harness I built that attaches to the factory wiring to facilitate not having to cut anything so in essence am still using the high level inputs. The amp sounds phenomenal at the upper end and is ear bleeding loud but I have no low end volume. I have good power connections using #10 wire to battery and short ground wire to back of radio and also am using Scott Ezzell's bracket to mount the amp (great bracket BTW) so my only thought is the older Harley radio in the '05 has better low end response than the HK but I wanted to pose the question to the forum and see what comes up.

Thanks,
Jack

 

this isn't going to directly answer your question since it sounds like you know what you're doing.

I have the 4 channel RF amp and RF165 speakers and the HK head unit on my '12 SG. I have the gain set at a bit past 1, basically the lowest settings. I have it set to AP (all pass) and that's how it likes it. My amp is just too powerful for the speakers. I get great all around volume and I can hear just fine on the "lower end" IF the engine isn't on.

With the engine on and me on the road, I can't hear much until it's past 3-4 bars. It was even worse stock.

 

Thanks for sharing your insight...Im glad to see im not the only one that has to turn it up to 3-4 bars to hear it. I called Tony at Iron Cross Audio today and he told me that the older radios (pre HK) were made by Radio Sound and in the case of my friends '05 Ultra Classic, were higher powered units in the order of 40 watts per channel. The HK units are only 20 watts per channel so that would account for the difference I was hearing after doing the install. So it is what it is. It still sounds good and I am very pleased with it for the money I have invested.

 

set the gain to just over 1 (like stated above)
run HI pass & then adjust your x-over to get some mids out of it too.
dont run the RCA connections use the hi level inputs, it makes a difference.



mine is LOAD AS HELL set this way & clear. also running foegate speakers

 

installed mine using the high level inputs and its awesome!

 

glad you like it

 

Does useing the high level inputs make a difference on aftermarket HU as well ?

Thanks-----

 

Yes it does make a BIG difference on my Sony Head Unit.

 

i cant speak from experience but from what ive heard it helps.