AI001

First my setup, I have PDX-5 in the boot, two front 4" diamond audio co-axial and two rear stock speakers with 2 earthquake subs under seat. Now the problem is a very annoying noise coming from rear speakers. HU is retrofitted CIC on hifi mode (four channels full range). Noise is like low frequency flutter (not too loud but very annoying) and intermittent but mostly present. Its only around idle revs. Even pressing on brake on idle changes its tune a bit. It doesn't come on all the revs neither its alternator whine or general pdx-5 amp hiss. It was all fine (or negligible/un-noticed) up until I installed a shielded cable for 6FL/6NR combox on the same path as speaker cable all the way from center console to the boot where combox is installed. Shielded cable is sharing cable path just from rear seats upto combox, max 1-1.5 meter.

I never heard of lying cables next to each other caused interference. What else could this be this? Also I have noticed a change in audio hiss if I turn on my lights (light switch set to auto or parking light) and reduces when lights are turned off. This is not noticeable but you can find if you listening for it. Are they related?

Any help will be greatly appreciated.

happy new year
Afsar

inktoxicated

i have the same electrical whine noise when i rev the engine. its actually coming directly from the passanger side rear tweeter. when we disconnect that tweeter it is gone. we changed the crossovers rerouted the wires did all sorts of stuff but its still there. even with the music completely off ull still get the whine. its not loud enuff for me to go nuts over it. i think its a possible connection from the stock wiring to the after market wiring that goes to my jl clean sweep. Im not digging thru all them wires tho to find outif thats the cause. i thought about getting a noise blocker for 5 bux from sonic. see if u can tell if its coming from one speaker. theyll tell u to try regrounding the amp to a diffirent spot. i tired all that and it didnt remedy the issue.

AI001

Mine is not alternator whine its intermittent flutter kinda noise only on idle revs. If engine is off all is silent (very very slight hiss, which I am not worried about).

bruce_miranda

This is a classic case of interference being picked up by voltage lines placed too close to audio lines. What may have happened is while you were running the new cable you've moved the old cable ever so slightly but enough to pick up. This is going to be a real bugger to fix.
I have a similar issue with my rear camera which is picking up some interference on the video.

AI001

This is bad news mate. Very very hard to find and find. I don't want to take back seat off again. Does noise isolator work?

stylin8o8

idk if this helps but i had a 2004 mustang gt with the mach1000 audio sound system and when i put in my aftermarket amp and 2 10" subs i had engine whine. it was because i did not unplug my stock subwoofer. when i unplugged it, no iengine whine or anything. good luck man

AI001

I would prefer rewiring my amp, I did use famous transparent speaker cable which is pointless and unnecessarily makes its handling difficult. I will rip them out and put other speaker cable.

BMW stereo system (best suited for after market amp upgrade) uses 4 heavily equalized output in stereo mode in CCC/CIC and if its HiFi (one step before TopHiFi/Logic7) then its 4 full range signal with CIC (I have retrofitted CIC). If you look at pinout at the quadlock connector those 4 channels are like 4x2=8 wires coming out it each carrying one channel (one wire for signal and another for ground). Given ground is generally common can I short all those 4 grounds and bring just one cable all the way to the back. Handling less cables are always easy. Handling four pair becomes really difficult and chances are high one of them will be close to power wire across their run and cause some kind of disturbance in the sound.

Other option for me is to use Alpine PXE-H660 which is value for money audio processor. If output is in full range mode Alpine won't use rear channels but just uses front channel to make rear channels.

If I go down the rewiring route then I will perhaps put cabling for centre channel and rear doors channel as well, I won't put anything there but just bare wiring to help me in future if I ever spend enough to get MS-8.

decision time...

bruce_miranda

I have a spare 2010 OEM Hi-Fi amp and a Logic 7 amp too for sale, if you want more choice.

syrousd

One of the most common types of car stereo noise comes from grounding issues. Improper grounding can introduce whine from your vehicle's alternator. Skip using existing body bolts or mounting places as they may be isolated or have coatings that can affect the connection. It is best to use solid chassis points and new installation hardware to ground your stereo or amplifier. There are other potential causes for alternator whine relating to grounding problems. These may include a grounding strap from the battery to the chassis as well as a solid mounting point on the engine.

Most car electrical components introduce small amounts of noise, especially accessories and power cables requiring high current draw. Running speaker cables and signal cables too close to these cables can pick up on noise that would otherwise not be heard. Purchase high-quality shielded twisted pair cables over traditional coaxial signal cables as a major key in suppressing this noise in your stereo system. It is also important that you ensure that you route your signal and speaker cables at least 18 inches apart from power cables when you install them in your vehicle to suppress noise.

Believe it or not all this makes a big difference in sound quality and performance, there are some aftermarket "filters" you can buy but I wouldn't waste my money on that, do it right the first time and you be noise free!!!!