Speakers make loud crackling noise at higher volumes

[dflillemae]

Hello,

I just bought a pair of new speakers (GAS Silver GS620P) and amplifier (Blaupunkt GTA4). After installing the speakers and amp to the rear deck i tested them out and i got some loud crackling noise whenever i turn the volume up to about 50% on the HU (kenwood kdc-w3041). The front door speakers are powered straight from the HU and work fine at all volume levels.

I have grounded the amplifier to a metal part on the driver side of the vehicle. My sub amp is grounded to the passenger side. The subwoofer has been running without any problems tho.

Also, i am running the 2 amplifiers from 1 set of RCA outputs, using 'Y' cables. Disconnecting the subwoofer amps RCA-s and only using the GTA4-s did not change the situation.

It seems like the problem seems to randomly go away. As driving around, i could occasionally turn the volume up pretty high without any problems and 5 minutes later the noise would come back.

There also seems to be an issue with ground loop as the new rear deck speakers make a sound that changes it's pitch with RPM of the car. Do you think that could be causing this problem? How can i fix that? I'm running rca-s and power cables from the opposite side of the vehicle, amps are grounded to a clean metal surface.

I tried running the speakers straight from my HU and bypassing the GTA4 amp and they worked fine.

Any assistance would be appreciated.
Feel free to ask more details if necessary .

David

[Kingstroker]

short in the Y? try running your rcas straight to your amp. I had a ground short in my amp that made the speakers pop. If the y isn't the problem, try isolating your amp from any metal and see if it stops

[dflillemae]

I tried running 2 channels without bridged mode and 1 set of RCA-s straight from the HU to amplifier and the problem is still there.

[Kingstroker]

what is your amp mounted to?

[frogcase2002]

Bottoming out? Is there a ssf on the amp?

[dflillemae]

what is your amp mounted to?

At the moment it's not mounted anywhere till i get this problem sorted out.

Bottoming out? Is there a ssf on the amp?

Nah, it only has HPF and LPF

[dflillemae]

Alright. I checked all the RCA connections. It seems like my amplifier rejects sending signal to 2 speakers at once. As stated earlier, i used a Y cable to split 1 set of RCA-s into 2 behind the HU (1 leads to sub amp and another to the GTA4, where i use another set of 'Y ' to use all 4 channels). My amplifier uses 1 set of RCA-s for channels 1 and 2 and the second set for ch3 and ch4.
If i plug only 1 set of RCA-s in channel 1&2 and leave the rest empty, i get clean signal into 1 speaker (bridged to both channels). Not bridging and connecting both speakers to channel 1&2 using only 1 set of RCAs makes the noise come back again... there also seems to be some weird squealing noise coming from the speakers, with it's pitch going up and down, but only with this kind of setup.
putting that same set of RCAs to channel 3&4 inputs made the same loud noise.

Could it be that all this is just too much for my HU?
If it's the RCA-s, shouldnt the amp still power both speakers non-bridged via channel 1&2?

This is getting really strange :/

Oh, and i got rid of the ground issue by putting both my amplifiers ground to the same location.

[its10v1]

I know you said you used the RCA cable straight to the GTA4 yet still got the same noise. Have you tried doing that since making a common/shared ground?

Personally I think your RCA cables are fine, to answer your question about powering both speakers non-bridged: Yes it should, the noise could be coming from a power wire that's running too close to your RCA's routing into your trunk. I'd look into Shielded RCA's (Kicker KX-Line for example.) If the noise(s) diminish when you eliminate the Y's and run the 1st set of RCA's to your GTA4, I'd say the ground was your issue all along. If not, then it's the amps RCA inputs. If you recently purchased it brand new, replace it. If it was purchased through a 3rd Party (a member on here, craigslist or resale of some sort,) you may want to open it and look at the input/output solder points.

Best of luck and hope I helped.

[dflillemae]

The amp is brand new. Running the RCA-s straight to amp still makes no difference. I just discovered that every time some lower frequencies play in a song, the power led of the amp dims and some weird frizzy sound comes from inside the amplifier and the rear speakers crackle and when increasing volume or when bass hits a bit harder, the speaker does not play for the duration of bass signal. At first i thought it was my subwoofer drawing too much power from the battery so i switched off the sub amp but the problem was still there.

All my RCA-s are shielded and more than 50cm apart from power cables at all times.

[Kingstroker]

I got 2 new pair of double shielded locking rcas on here cheap. while the amp is on push the body of the amp up against a ground surface. It doesn't matter if is is grounded properly. random popping sounds like a short, whines and hums are more from interference from unshielded rcas or ground loop issues. someone step in here and correct me

[its10v1]

If you're not getting the same popping sound from your sub amp, I'd have to say it's something to do with the internals of the GTA4. No offense, it may have been the GTA4 all along.

The Frizzing sound you're hearing sounds like an engine whine with some static. I had a problem with engine whine/alternator hiss in my first system (Powered 8" Dual 200w RMS in a '96 Chevy Corsica.) Solved it by finding a better ground and using different power/ground wire. Had been using 8ga House wiring (Stiff copper that doesn't bend easily,) and like 10ga for a ground. Bought ~15ft of Q-Power 4ga, installed it, moved the ground to a spot I sanded down with some very coarse sand paper, no more whine/hiss.

[dflillemae]

I'm not sure what i should do now... I've tried pretty much everything i have come up with

It's still strange that the speaker works fine if i put the rca only to channel 1 and 2 but putting the very same RCA set to 3&4 makes the speakers go crazy.
Do you know a good ground spot for Audi a4 b5 saloon?

[dflillemae]

Alright, it appears the subwoofer which is connected to another amp seems to start crackling with the rear deck speakers aswell. But not when ONLY sub RCA-s are connected to the HU.