alright gents, here's a real tickler. a guy i work with has been working on a 2001 BMW 3 Series. He bypassed the factory amplifier and ran aftermarket components and a two channel boston amplifier running off the stock head unit. the ONLY speaker in the ENTIRE car that has alternator whine is the right front tweeter. it is an aftermarket Boston tweeter running through the provided crossover for the components. we have tried absolutely everything imaginable to get rid of the noise, and it either stays the same or gets worse. it's not a ground problem, or RCA. the thing is, the woofer running through the same crossover doesn't have any noise whatsoever, while the tweeter is pretty bad.
any suggestions?? we've tried grounding rca's, noise filters, everything imaginable. we are clueless.
-UK
Replies (6)
Victor on 06/30/2007 03:22:28
Components in a Xover have an affinity to pick up unwanted disturbances from the surrounding electro magnetic feild. even if the feild is a weak one you may sometimes see such an issue.
Did you try re-locating the Xover and the tweeter.....??
try to extend the wire and pull the Xover and the tweeter totally out of the car and see if the whine is still there...
check the integrity of the wire used to connect the Xover to the amp and the tweeter to the Xover... some minor cuts while installing or poorly insulated wires can also pick up noise...
Victor...
Also did you try switching the left and the right tweeters to see if the issue is with a particular tweeter or with the install...?
I am assuming that
http://www.termpro.com/articles/noise.html
these have definitely been taken care of.....
swez on 06/30/2007 08:13:44
Maddening process huh? The guy who wrote that article on noise at termpro is onto a lot of the common causes and less common ones too. But what he says about back tracking is dead on. (eg. finding the point where the noise starts by the process noted)
I agree w/ Victor about checking this part of the system and isolating them from factors not known at the moment. At this point, I would start at the amp outputs for this channel and see if the noise is present there. Here, a full range test speaker may be most helpful.
1. Connect a known good test speaker (Full range) to the amp channel that is feeding the right/front Comp speaker. If you hear noise, the problem is either in the amp or upstream signal paths are picking up noise.
2. If there is no noise in the test speaker, upstream wiring and amp are probably OK. The problem is between the amp and speakers. Once this has been isolated by the test speaker, one needs to look closer at the wiring from amp to crossover, crossover to speakers, (Woofer and tweeter) and the crossover itself.
Once he has isolated the general source of noise intrusion, then we look up or downstream to figure out what part of the install is picking up noise and track it back to front of a given signal path.
Tech Tip: Speakers generally only reproduce signals they are given. If the signals they get have noise riding on it, they reprodce the noise and signal. If the noise is induced by something along the speaker lines only, we take one approach.
If the signal is noisy at the amp stage or upstream of the amp, we look for the obvious first. (RCA line locations, RCA line integrity, amp output isolation from chassis ground or noise from the HU source.
Each step can be checked by several methods. The easiest place to start, is swapping L/R RCA inputs at the amp. If the noise shifts for the right to left speaker, we can assume the amp to crossovers to speakers are OK. The problem is either amp related or upstream signals that feed the amp.
If the noise remains on the R/F speaker only, upstream signals and amp are OK. We then concentrate on the right speaker wiring and crossover integrity.
Got all that?
Swez
cplkittle on 07/1/2007 08:07:43
If the battery is still in the trunk like the 90's models, you have a 1/0 gauge battery wire running up the right side of the car from the battery to the alternator and fusebox. I would assume that this might be part of the problem.
Where is the crossover?
The reason the tweeter gets the sound and the midbass dosen't is that the tweeter's filter range does not include the frequency of the interference. It is filtered out through the crossover for the midbass.
In this case, one would assume the interference is being picked up prior to the crossover.
my troubleshooting techniques would include:
-swapping crossovers to make sure the prob wasn't a bad crossover
-run the wires up the middle of the car and then to the door to rule out the battery wire interference.
-switching the left and right RCA inputs, switching left and right outputs.
Victor on 07/2/2007 11:41:57
Any luck yet ...??
UKinstaller on 07/8/2007 11:37:56
sorry for the delayed response, i took off to Orange Beach alabama for a week of fun in the sun.
anyway i talked to the guy that was working on the car, and it ended up being a faulty crossover pack. we snagged some out of another set, problem solved.
thanks for the input guys.
-UK
swez on 07/8/2007 22:56:07
Interesting.... that was the logical place to look first.
Swez
any suggestions?? we've tried grounding rca's, noise filters, everything imaginable. we are clueless.
-UK
Replies (6)
Victor on 06/30/2007 03:22:28
Components in a Xover have an affinity to pick up unwanted disturbances from the surrounding electro magnetic feild. even if the feild is a weak one you may sometimes see such an issue.
Did you try re-locating the Xover and the tweeter.....??
try to extend the wire and pull the Xover and the tweeter totally out of the car and see if the whine is still there...
check the integrity of the wire used to connect the Xover to the amp and the tweeter to the Xover... some minor cuts while installing or poorly insulated wires can also pick up noise...
Victor...
Also did you try switching the left and the right tweeters to see if the issue is with a particular tweeter or with the install...?
I am assuming that
http://www.termpro.com/articles/noise.html
these have definitely been taken care of.....
swez on 06/30/2007 08:13:44
Maddening process huh? The guy who wrote that article on noise at termpro is onto a lot of the common causes and less common ones too. But what he says about back tracking is dead on. (eg. finding the point where the noise starts by the process noted)
I agree w/ Victor about checking this part of the system and isolating them from factors not known at the moment. At this point, I would start at the amp outputs for this channel and see if the noise is present there. Here, a full range test speaker may be most helpful.
1. Connect a known good test speaker (Full range) to the amp channel that is feeding the right/front Comp speaker. If you hear noise, the problem is either in the amp or upstream signal paths are picking up noise.
2. If there is no noise in the test speaker, upstream wiring and amp are probably OK. The problem is between the amp and speakers. Once this has been isolated by the test speaker, one needs to look closer at the wiring from amp to crossover, crossover to speakers, (Woofer and tweeter) and the crossover itself.
Once he has isolated the general source of noise intrusion, then we look up or downstream to figure out what part of the install is picking up noise and track it back to front of a given signal path.
Tech Tip: Speakers generally only reproduce signals they are given. If the signals they get have noise riding on it, they reprodce the noise and signal. If the noise is induced by something along the speaker lines only, we take one approach.
If the signal is noisy at the amp stage or upstream of the amp, we look for the obvious first. (RCA line locations, RCA line integrity, amp output isolation from chassis ground or noise from the HU source.
Each step can be checked by several methods. The easiest place to start, is swapping L/R RCA inputs at the amp. If the noise shifts for the right to left speaker, we can assume the amp to crossovers to speakers are OK. The problem is either amp related or upstream signals that feed the amp.
If the noise remains on the R/F speaker only, upstream signals and amp are OK. We then concentrate on the right speaker wiring and crossover integrity.
Got all that?
Swez
cplkittle on 07/1/2007 08:07:43
If the battery is still in the trunk like the 90's models, you have a 1/0 gauge battery wire running up the right side of the car from the battery to the alternator and fusebox. I would assume that this might be part of the problem.
Where is the crossover?
The reason the tweeter gets the sound and the midbass dosen't is that the tweeter's filter range does not include the frequency of the interference. It is filtered out through the crossover for the midbass.
In this case, one would assume the interference is being picked up prior to the crossover.
my troubleshooting techniques would include:
-swapping crossovers to make sure the prob wasn't a bad crossover
-run the wires up the middle of the car and then to the door to rule out the battery wire interference.
-switching the left and right RCA inputs, switching left and right outputs.
Victor on 07/2/2007 11:41:57
Any luck yet ...??
UKinstaller on 07/8/2007 11:37:56
sorry for the delayed response, i took off to Orange Beach alabama for a week of fun in the sun.
anyway i talked to the guy that was working on the car, and it ended up being a faulty crossover pack. we snagged some out of another set, problem solved.
thanks for the input guys.
-UK
swez on 07/8/2007 22:56:07
Interesting.... that was the logical place to look first.
Swez
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