Speaker Whine after amp upgrade -- help

[abarrett]

A little backround first -- 2013 g23 -- Boat had all stock in boat polk speakers. 4x roswell horn speakers on tower and stock sub, also stock 4000.4 and 5000.5 amps. After doing some research I decided to upgrade all inboat speakers and also add a new rockford 650x4 amp to power the tower speakers. My plan was to redistribute the stock 400 and 500 watt amps to various sections of the boat. So anyways I recently installed the new amp myself and had someone else transfer the speaker wires. When installing the new amp instead of using a distribution block for power I simply ran new power cables from the battery on the port side up to where the new amp was mounted. (right below the 2 factory) The new power cables came with an inline circuit and that was installed as well about 16 inches from the battery connections. For now we left all inboat speakers and sub on the 5 channel and just moved the tower to the amp for testing so the 400w tower amp is currently not in use. Now howveer whenever the boat is running we get a terrible speaker whine from the tower speakers. As we accelerate the whine gets louder. When the boat is only on accessory there is no whine the the tower speakers sound great. I have read enough to know it is probably some kind of alternator noise or something. Is it possible I just need to install some type of noise filter on the added power cable Also occaisnolly we will get some a "crackle" or "popping" sound from the inboat speakers. I found this interesting because only the speakers were changed out and wattage was not messed with at all.. I have checked all grounds to the new amp and they appear to be good. Thanks for your time, any suggestions are welcome.

[MLA]

Out of curiosity, what actual model rockford amp did you go with? a search for a 650x4 does not come up with anything. That 400W tower amp actually is delivering 125W rms to each of your 4 pods, so 500W. total to your tower setup. Would hate to see someone go backwards on power for a setup thats already under powered. If Rockford is your brand, then the T1000.2 would be the choice for 4 HLCD tower pods.

Sounds like the newly installed amp does not share the same voltage reference as the rest of OEM audio equipment. The individual that transfer the speaker wires, are they an experienced marine audio installer? If so, them start from the beginning and do the installation for you.

[abarrett]

Out of curiosity, what actual model rockford amp did you go with? a search for a 650x4 does not come up with anything. That 400W tower amp actually is delivering 125W rms to each of your 4 pods, so 500W. total to your tower setup. Would hate to see someone go backwards on power for a setup thats already under powered. If Rockford is your brand, then the T1000.2 would be the choice for 4 HLCD tower pods.

Sounds like the newly installed amp does not share the same voltage reference as the rest of OEM audio equipment. The individual that transfer the speaker wires, are they an experienced marine audio installer? If so, them start from the beginning and do the installation for you.

Sorry it is the Rockford Marine PM600x4.. That was what he recommended. When the boat is off the new amp absolutely provides more power and volume to the tower is sounds way better. But like i said once the motor is running it gives them a terrible alternator whine. The installer typically does car audio but seemed to think it would be a difficult job.

[MLA]

When the boat is off the new amp absolutely provides more power and volume to the tower is sounds way better.

I cant argue sounds better. Could be a handful of things that impact this. And if you move that old amp over to other speakers, whats to say those issue dont move right along with it. As to more power. The PM600.4 is actually 50W rms less, to each tower speaker compared to the D4000.4. Or 200W rms. cumulative.

If the D4000.4 was tuned correctly and you noticed a drastic difference in volume simply swapping amp, then that D4000.4 has an internal issue.

[abarrett]

Sounds to me like the 4000.4 had some sort of issue then because it hardly provided much sound at all. I am more worried about fixing the whine at this point.

[swatguy]

MLA is the expert what I haven’t seen yet is where you pulled your ground from for the new amp. That makes a huge impact as well. If you’re hearing a whine that changes with rpm speed it’s usually a voltage /ground issue .


Try and pull the power and ground from the same location the factory amps did.

[MLA]

If it is determined that there is an issue with the OEM 4000.4 and you decide another amp is in order. Use the PM600.4 for what you had planned to use the 4000.4, and get you a solid 2 channel amp for those 4 HLCD tower pods. As an example, the PM500.2 is more wattage then your new PM600.4, for $70 less. But if you wanted to really wake them up, the P1000.2 is the amp, and its actually less expensive then the new PM600.4.