Tower speakers crackling at low volume

[killerbren]

Hi guys, new (used) boat, still figuring out all the gremlins.

I'm not sure if the speakers are shot or what the issue is on this. The tower speakers are on a separate zone, so I can isolate the volume of the tower speakers without messing with the rest of the boat. When the volume is low, the tower speakers crackle and pop and just sound terrible in general. I do get to a point where if the volume is high enough, the crackling goes away and the speakers sound normal.

What does this mean, is it the speakers? is it the amp? is it interference?

It is both speakers doing this, not just one.

Ive attached a video below, the first 5 seconds or so I have the volume low, then I turn the volume up until 10 seconds, then down, then up.

[chpthril]

i would start by swapping the tower speaker RCA with the in-boat RCA and see of the problem stays or moves. This divides the issue up and narrow it down. If the problem moves, its coming from the source unit. If it stays, its from the amp to the speakers. An ohm check on the speaker might reveal something. Disconnect the leads at the pod and measure. Should be close to 4 ohm, give or take a .5 ohm.

[killerbren]

Okay, checked the ohms at the speakers and im getting 4.1.

the amp is a rockford r300-4, 300 watts, 4 channels. It is set up so that each tower speaker uses a channel, and the sub is using the other two channels and is bridged.

I see that the power and ground, and all the inputs and speaker wire are all bundled together starting from about 1.5 feet from the amp. Would it help to separate the wires from the power cable even though it is only 1 foot?

Im still working on switching the rca cables.

[killerbren]

right now there is a RCA labeled "Subwoofer" from the back of the deck which goes into one of the rca inputs on the amp. There is another pair that is labelled "zone 2" which goes into the 2nd input on the amp (tower speakers). There are 2 more rca connections coming out of the deck labeled "front" and "rear" and these are unused. I moved the rca from the "zone 2" connection to the "front" connection and the problem remained.

All speakers for the boat (except the tower and the sub) are spliced directly into a wiring harness and it connects to the back of the deck. There is no rca for them so I cant swap plug them into the "zone 2" rca to see if the problem moves to those speakers.

[chpthril]

Take the head-unit and RCA cables out of it completely by using 3.5mm x RCA into the tower speaker inputs on the amp.

Im assuming this is a new problem, but its worth checking to make sure the cross-over filter switch for the half of the amp driving the towers, is set to hi-pass and the frequency is at least 100 hz or higher.

Next is going to take some time. You will need to pull an in-boat speaker, unplug its wires, connect a jumper that will reach the tower amp and then reinstall the speaker. pull the tower speaker leads from the amp but make a mental note of how they were connected. Now wire up the jumper wire and listen to that speaker to see if it breaks up like the tower speakers did.

This will either point to the amp or point to the speakers themselves being blown.