2009 FLHT, Biketronics controller, Alpine CDE-hd149BT H/U, Alpine KTP-445U amp, running POLK DB651 in fairing and polk BD570 in the lids.

I ran a dedicated power wire to the amp from the battery and grounded it by the head bearing ground. The amp case is attached to the top of the head unit via velcrow to the vinyl sheet preventing the water to get to the H/U.

Whenever I apply the front brake, a popping sound comes from the speakers.

Should I run a dedicated ground to the battery? Or could this be something else?

 

Strange. . . The only electrical thing that happens when you apply the front brake is the brake lights come on? Dedicated ground to the battery would be a good place to start. But I can also tell you from experience those polk DB651's have a history of that popping sound you speak of. I don't know if that's your issue or not but IMO those speakers are suspect. On the other hand you are not putting very much power to them with the Alpine amp so they should be fine. I'd go in and check all my wiring connections and ground at the battery.

 

GTG that will be my next step.

Should I ground the AMP chassis?

 

No Sir. . . The amp should be fine if you ground to the battery.

 

sounds like you're getting a voltage surge when applying brakes which more than likely correlates to a bad ground. But I don't think it's your amp ground although as Gannicus pointed out, always best to run grounds back to battery on these audio setups.

Take a look at your ground cable on your battery and where it attaches to the case. Both ends of it. Clean any corrosion and use a dab of blue Loctite when attaching the cable back to the battery.

 

I had a similar problem many years ago without the amp. learned that i had a flakey ground between the front end and the chassis. Maybe you have enough play in your neck bearing to allow a ground goung thru the neck bearings to break when the clearance is transferred witht he braking action. For mine I simply ran a dedicated ground from the battery along the backbone through the inner fairing and landed it on the radio chassis.

 

Ran the dedicated ground still pops when front brake is applied. Only the front not the rear. i'm at a loss.

 

Pulled the brake relay it did not do it, swapped relay with the efi relay it still pops.

 

Your issue is ground related. Try attaching a piece of wire from chassis of amp to chassis of radio

 

Totally agree with Nutz. . Ground related issue. Just a PITA to find sometimes. If the wire from chassis to chassis doesn't work. Try another set of speakers ( if you have some laying around) to see if they are popping as well. If they are. . .It takes us back to ground zero. . .No pun intended. . .lol