Car speakers making humming/crackling noise after installing aftermarket stereo

Question

So over a year now i had installed an aftermarket stereo which worked perfectly fine for a couple months after installing it properly making it a molex connector as a new harness.

Fast forward, the front right speaker started making some crackling noises and a humming sound, NOT from the engine or alternator, just a steady humming noise that got louder over time. Eventually it got so bad that i disconnected that speaker and thought it was blown out so i planned on changing it later on.

Fast forward again a couple weeks and the right back speaker starts doing the humming as well and i disconnect that one too. I thought that maybe i made the molex connector really crappy since it was my first time making one so i remade the harness but the issue still persisted.

Earlier this month i finally was able to get some new aftermarket speakers and installed them recycling the old wiring as replacing them would be way too much work for me and i use my car daily.

So as i installed the new speakers i tested them along the way and they sounded perfectly fine. When i was done installing 3 of them i went to a test drive to pickup some food and the issue came back starting in the same spot, front right. It started crackling this time and then it started to humm. The humm is like the humming noise a microphone makes when its not connected properly.

I reached out to a buddy of mine who is a mechanic and he said that i needed a noise filter/suppressor. So i went out to buy one that was meant for speakers of up to 100 watts but my speakers are peaking at 300watts, min is 150watts.

After i installed the filter i tested them again and it did help it quite a bit but after a couple minutes the crackling starts, not to bad but noticeable, humms for a while and then the audio on that speaker gets reduced a LOT, and this time its the whole right side speakers whose volume gets reduced. It also started shutting off the sound completely on all speakers, kind of like a pop. As if you were to disconnect your earphones from your phone and then plug them back in, that's what it sounds like and it cuts for a brief second.

I'm a big DIY person and really would like to resolve the issue myself, if possible. Any idea what is going on? I kind of figure that i need a stronger filter but what if that doesn't solve everything?

I remember that on the original harness, the speaker wires were twisted all the way, not sure if this will really have that much of an impact especially by the way they have gone out one by one. I also read that there may be some sort of ground loop? How would i be able to troubleshoot this?

Any ideas are appreciated.

Answer 1

Sounds like a typical weak ground issue. Check the engine to frame/fender ground as well as the gauge of the wire used for your amp (if it's an external amp run directly to the battery). If you added an amp and wired power to the fuse box,(other than the switched power to turn on the amp) run it directly to the battery instead. Noise suppression filter is one common solution but will simply filter ground noise, ignore your speakers wattage rating as it means absolutely nothing, especially in this case.

I've had countless people come to me stating they have 500W speakers but they can only handle that peak for a few seconds before blowing, especially with a cheaper amp that provides poor power. Under powering speakers is FAR more damaging to a speaker than too much 'clean' power.

Answer 2

amp says 10 awg power cable.i used 10 amp cable.i connected the earth to the boady.i did not have this sound when i did a prefit.when i put things together i started having this problem.also from the amp to the speKer harnesss i am using just some speaker cables i got whn i bought soeaker.and the RCA cables are just flexible normal brand.does these 2 have to be of good quality cables.

this is a 4 chanel amp.i connected 2 sets of rca to the amp from the head unit.and changed the switch to 4 chanel in the amp.ehen i removed in set of rca still all 4 speakers had sound.

thank you for your help.