| RobK |
Recently I finished upgrading the speakers, sub, and amp in my '03 Touring. The amp is a Rockford Fosgate which I installed under the driver's seat, the front speakers are Infinity Kappa Perfect's (components), the rear speakers are Infinity 6002i, and the sub is the Polk GNX104. The rear speakers are run off the stock amp. I ran new speaker wire everywhere because I wanted to minimize cutting into the factory harness and besides, I thought it would be easier to mount the crossovers (which are fairly large) inside the cabin rather than in the door.
Anyway, so far I am unimpressed with the sound of the system. One thing I hated about the crappy Bose system was that there was no "depth" to the music, and the mid's sounded hollow. Same thing with the new system. Maybe the speakers just need to break in...I'll give it a few weeks and we'll see!
Here's the problem. After installing all of this stuff, I get an annoying buzz at low RPM's and a high pitched whine at high RPM's. Sounds like a dentists drill when you're driving :(
I have done all the normal troubleshooting - such as being sure the power cable from the battery is separate from the RCA's (they are - the power cable was run on the left side of the X, through the bottom of the door sill and under the seat, whereas the RCA's and speaker wire are run in the center console next to the seat). I also tried relocating the ground for the amp and that made no difference. The contact point for the ground has been heavily sanded to remove primer and paint, so that can't be the problem.
It sounds to me like it's some sort of ground loop problem but for the life of me I cannot figure out what to do next!!
One thing I did that reduced the noise by about 75% was to ground the negative side of the female RCA's that I patched into the front Bost amp. If I remove that ground, the noise is much louder. Also, the noise has infiltrated itself into the rear speakers, which is strange because those are still run off the stock amp and wiring, not the new amp.
Does anyone have some ideas on what to try next? I'm at my wits end on this one!!
Thanks!
-Rob- |
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| RobK |
Thanks for the tip - but, I followed the advice of a site that said to put a muting plug into one of the rca inputs of the amp. If the noise goes away, the problem is not caused by the amp, or its wiring - the noise is coming from somewhere else.
I put the muting plug in, and the noise disappeared. I *think* this means that the wiring to/from the amp is ok, and the noise is probably coming from one or more of the rca inputs. If I'm right, I would think that a filter on the alternator would not solve this problem.
What do you think?
Thanks!
-Rob- |
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| DaleB |
quote:
Originally posted by RobK
Thanks for the tip - but, I followed the advice of a site that said to put a muting plug into one of the rca inputs of the amp. If the noise goes away, the problem is not caused by the amp, or its wiring - the noise is coming from somewhere else.
I put the muting plug in, and the noise disappeared. I *think* this means that the wiring to/from the amp is ok, and the noise is probably coming from one or more of the rca inputs. If I'm right, I would think that a filter on the alternator would not solve this problem.
What do you think?
Thanks!
-Rob-
Assuming you have a cap readily available it would be quicker to see if it fixes it before troubleshooting the interconnects. You could have bad ground on an interconnect, which would introduce noise, just like at home you would get 60 Hz hum.
Try the cap first, it's easier. |
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| whynotmdx |
You just put the capacitor/filter on the power line to the amp. Generally a good idea anyway.
However if you think the noise is on the RCA you can use a ground loop isolator there as well. Some people think it has a detrimental effect on the sound quality though so it is generally not the first choice. |
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| RobK |
Sounds easy enough. I'll try it. The only other thing I can think to try is to pull the head unit out and try grounding it at the same place the amp is grounded. I hate to pull all that stuff out of the dash though, but the whine is REALLY annoying!
-Rob- |
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| RobK |
| FYI: I found the common ground for the head unit without pulling the dash apart. I tried grounding the head unit to the amp ground thinking that would fix the whine, but it made absolutely zero difference. |
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| pacpal1 |
RobK:
1) Where have you grounded your amp(s)...try the post to one of the rear (third row) seats...this worked great for me...I have two amps mounted in the rear storage compartment grounded to a single third row seat post and an aftermarket head unit grounded to the factory ground wire once used by my Bose head unit. I am experiencing absolutely no engine noise under all conditions (i.e., headlights on, etc.)
2) What kind of amp are you using...what kind of buttons does it have...I have an a/d/s/ amp that has a "balanced/RCA" button...the setting of this button may affect signal quality.
3) Where are all of your components located....at one point in my system design I had an equalizer mounted in the cubby hole beneath the "Not an Ashtray" (i.e., on top of the transmission housing). I found that the transmission housing may be an area of very high electronic interference due to the positioning of an electic fan/motor assembly mounted in front of the shift mechanism...I'd advise you to stay away from this area. |
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| RobK |
quote:
Originally posted by pacpal1
1) Where have you grounded your amp(s)...try the post to one of the rear (third row) seats...this worked great for me...I have two amps mounted in the rear storage compartment grounded to a single third row seat post and an aftermarket head unit grounded to the factory ground wire once used by my Bose head unit. I am experiencing absolutely no engine noise under all conditions (i.e., headlights on, etc.)
The amp is placed under the driver's seat, and is grounded on the front right bolt for the seat. I picked this place because another member (koolkat I believe) said he had great luck with it and it required the least runs of wire.
2) What kind of amp are you using...what kind of buttons does it have...I have an a/d/s/ amp that has a "balanced/RCA" button...the setting of this button may affect signal quality.
It's a Rockford Fosgate Power 551X. There's no button on it like you describe unfortunately!
3) Where are all of your components located....at one point in my system design I had an equalizer mounted in the cubby hole beneath the "Not an Ashtray" (i.e., on top of the transmission housing). I found that the transmission housing may be an area of very high electronic interference due to the positioning of an electic fan/motor assembly mounted in front of the shift mechanism...I'd advise you to stay away from this area. [/B]
The components are located in the cubby hole in front of the transmission area around the airbag module. I thought this might be a noisy place also, so I tried moving everything away temporarily to see if it would help, and it did not.
Thanks for the tips - I will continue to pull my hair out on this until there's none left :)
I think my next thing to try is to splice a couple of new rca plugs into the factory wiring harness. Perhaps the ones I am using are junk and introduce a lot of noise...
-Rob- |
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| zubinh |
| Radio Shack has a ground Loop noise filter. |
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| RobK |
quote:
Originally posted by zubinh
Radio Shack has a ground Loop noise filter.
I was there today and saw one - however, I've heard they are the absolute last resort because they tend to filter out the "good" frequencies of the music too. But, it looks like I may have to take this route since I can't figure out what is causing the noise...
Thanks
-Rob- |
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| ron@se |
| 1st question....what did you use to get the sound from the factory headunit to the aftermarket amp. If you used an LOC, what brand, and what kind of RCA's are you using??? |
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| RobK |
quote:
Originally posted by ron@se
1st question....what did you use to get the sound from the factory headunit to the aftermarket amp. If you used an LOC, what brand, and what kind of RCA's are you using???
Here's what I did...
I went to Radio Shack and bought 4 shielded male RCA wires. I then cut the 8 related low-level signal wires coming from the HU. I spliced in the RCA wires according to the wiring diagram using butt splices. None of the wires were terminated, just spliced into so all the signals still go to the stock amp. Reason being, the front 2 speakers and the new sub are run off the aftermarket amp, but the rear 2 speakers are run off the stock amp.
The RCA's are Rockford Fosgate shielded (they are ridiculously long - 15 feet because I could not find 6 foot!), something like $20 a piece from Best Buy. They look pretty heavy duty. I tried a cheap set of RCA's in order to make sure there wasn't a problem with the RF RCA's or how I routed them - and that did not help one bit.
One thing I have not messed with is the remote turn on wire - is there any possibility of this introducing noise into the system somehow? I also spliced into the factory harness to get access to this signal. I used the wire that came with the amp install kit.
Thanks, and I hope you have some ideas or I will soon be bald :)
-Rob- |
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| pacpal1 |
Have you tried grounding your amp to the third seat post?...this worked for me when I had amps connected to the factory head unit. You still haven't stated where you're grounding your amp.
BTW, if I were you, I'd buy another amp before I'd use a filter...many members of this site have mounted amps (either in conjunction with retaining the Bose or non-Bose factory head unit, or in conjuction with the installation of an aftermarket head unit) without experiencing ANY alternator noise.
In addition, I'd avoid mounting any electronics near the transmission housing...I know you've moved your equipment out of that location on a test basis, but, as I stated earlier...I have experienced severe alternator whine when my system was in a state of configuration where an equalizer was mounted in that vicinity. |
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| RobK |
BTW, this might provide a clue as to what is causing my noise problem. I get the whine from the rear speakers too, which is very strange because the rear speakers are still run off the stock amp. Somehow my addition of the amp and splicing into the harness at the stock amp produced noise in the rear too.
I spliced into the rear signal wires in order to get the signal for my Polk sub. I don't know how or why, but noise must be coming in from here. Also, as I said earlier, I ran new wire to the speakers that are powered by the new amp.
-Rob- |
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| pacpal1 |
| Oh...BTW...the remote turn on wire is not the problem...it simply sends a signal to turn the connected component on or off. |
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| RobK |
quote:
Originally posted by pacpal1
Have you tried grounding your amp to the third seat post?...this worked for me when I had amps connected to the factory head unit. You still haven't stated where you're grounding your amp.
BTW, if I were you, I'd buy another amp before I'd use a filter...many members of this site have mounted amps (either in conjunction with retaining the Bose or non-Bose factory head unit, or in conjuction with the installation of an aftermarket head unit) without experiencing ANY alternator noise.
In addition, I'd avoid mounting any electronics near the transmission housing...I know you've moved your equipment out of that location on a test basis, but, as I stated earlier...I have experienced severe alternator whine when my system was in a state of configuration where an equalizer was mounted in that vicinity.
Oops, I messed up my original reply to you - I did say where I grounded the amp but my answer showed up in the quote section :( Sorry!
Anyway, the amp is located under the driver's seat, and I grounded it at the front right bolt holding the drivers seat down. Someone else (koolkat I think) said he had good luck with grounding here. I scraped the paint off, and sanded everything to bare metal. I tried moving the ground to another seat bolt in desperation and it made zero difference.
Thanks for the tips.
-Rob- |
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| pacpal1 |
| Could the ground of your aftermarket amp be affected by the ground of the Bose amp? I just noticed that you state you've retained the Bose amp to run the rear speakers...this is something I never did and I haven't noticed anyone else say they've retained the Bose amp. Try disconnecting the Bose amp altogether. Unfortunately...all you can do is continue the process of trial and error until you isolate the problem. You should take comfort in the fact that MANY installations have been completed without any noise whatsoever...so you have done something wrong/incorrect/out of the ordinary. |
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| RobK |
quote:
Originally posted by pacpal1
Could the ground of your aftermarket amp be affected by the ground of the Bose amp? I just noticed that you state you've retained the Bose amp to run the rear speakers...this is something I never did and I haven't noticed anyone else say they've retained the Bose amp. Try disconnecting the Bose amp altogether. Unfortunately...all you can do is continue the process of trial and error until you isolate the problem. You should take comfort in the fact that MANY installations have been completed without any noise whatsoever...so you have done something wrong/incorrect/out of the ordinary.
I performed the same installation as Koolkat1973, as described in this thread:
http://www.acuramdx.org/forums/show...&threadid=11790
The only difference that I can see is the fact that I ran new speaker wire to every speaker driven off the new amp. I don't see how this could cause any noise in the system.
I had the same thought as you - perhaps there is some kind of problem introduced by using an aftermarket amp with the front 2 speakers, and the stock with the rear. BUT, if this were true, then unplugging the stock amp would cure my noise problem, would it not? It doesn't.
I do take *some* comfort in the fact that many have good, clean installs :) And you're absolutely right, I've done something wrong or strange that is causing this problem. So far my process of elimination has not revealed anything! The saga continues..... |
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| pacpal1 |
| Where are you getting power for you aftermarket amp? Directly from the battery? |
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| RobK |
quote:
Originally posted by pacpal1
Where are you getting power for you aftermarket amp? Directly from the battery?
Yep. Ran the wire directly from battery, through rubber grommet in firewall left of the steering column, down along the driver door sash, and under the driver seat near the fuel door latch.
-Rob- |
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| ron@se |
| I'm pretty sure your RCA's are the problem here.....I have done enough MDX installations to know what does and doesn't work. Cutting the ends off the RCA's is the first culprit.....even though you don't need them, I would still have run an AudioLink LOC from the preouts behind the factory radio....reason I do this is it eliminates A LOT of noise. The only other thing I would have done different other than that is used higher quality wires, specifically Phoenix Gold Reference series....we use those w/the AudioLink combo ALL THE TIME now and get ZERO noise. Again, the AudioLink IS NOT necessary to attain the signal you need, we simply use it for noise reduction WITHOUT signal loss....using a ground loop isolator will GREATLY diminish your signal, specifically the low end. |
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| wlmdx |
Robk,
I have the same problem as yours. I have Alpine F340 underneath the driver's seat and an Alpine EQ installed beneath the "none an astray" . Bose head unit. I get the buzz when the radio is on even with the volume turned to zero. I can still hear the buzz with the engine turned off and high pitch whine at any RPM. The buzz seems much louder with the EQ connected. What is your cure?? |
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| pacpal1 |
wlmdx:
FYI...my stereo system has undergone many iterations. In one of it's earliest, while I was attempting to retain the Bose head unit, I had mounted an Alpine ERE G180 graphic equalizer in the pocket beneath the "not an ashtray". I beleive this mounting position was the cause of a significant amount of electronic interference...If you'd ever disassembled the transmission housing, you'd agree...there's an electric motor driven fan mounted just ahead of the shift lever. I'm not saying this is definitely the cause of your engine noise, but it was for me...as soon as I moved the equalizer to another position, the noise disappeared.
I am now using an aftermarket head unit (Alpine 9813) as well as the ERE G180...they're both mounted in the space once occupied by the Bose head unit...apparently far enough away to not be affected by the electronics mounted near the transmisstion lever. |
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| wlmdx |
| I seems to experiencing 2 different noises. The buzz(sounds like air leak) when the radio is on and volume turned to zero. The whine in any rpm with radio is off. I hear both when I drive>:confused: |
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| RobK |
quote:
Originally posted by wlmdx
Robk,
I have the same problem as yours. I have Alpine F340 underneath the driver's seat and an Alpine EQ installed beneath the "none an astray" . Bose head unit. I get the buzz when the radio is on even with the volume turned to zero. I can still hear the buzz with the engine turned off and high pitch whine at any RPM. The buzz seems much louder with the EQ connected. What is your cure??
I was certain my noise was caused by a ground loop because of the whine that matched the engine RPM. With the engine off, there was zero noise. I tried moving grounds, moving wires, etc., and after wasting at least 2 days trying to figure it out, I went to Radio Shack and spent $15 on a ground loop isolator. Problem solved.
A lot of people said I should not use such a device, because it would filter out "good" frequencies, but I noticed no difference in the quality of the sound whether the isolator was hooked up or not. So I'm happy with my solution!
One thing to try is a muting plug, which is just an rca end with its positive and negative wires hooked together. This will tell you if the problem is upstream or downstream from wherever you plugged in the muting plug. In my case, I plugged it into the amp's inputs, and the buzz/whine went away, so that told me it was not the amp or anything behind the amp (ie., speaker wires, speakers). It might help to save you a few hours tracking down your problem.
Good luck!!
-Rob- |
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| HotlantaMDX |
Robk,
This is what I have done in the past and works...
* uses quality RCA cables (it does make a difference)
* run amp power cable on one side of vehicle and all signal and RCA cables on the opposite side
* make sure the grounding cable for the amp is as short as posible
* make sure the grounding cable for the amp is the same size or larger than the amp power cable
* check the resistance between all your grounding points, make sure there is not a big difference between them
* re-enforce the main battery ground with a larger gauge grounding cable
that's all I can think of rightnow, but try these and let me know if it works. Good luck. |
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| RobK |
quote:
Originally posted by HotlantaMDX
Robk,
This is what I have done in the past and works...
* uses quality RCA cables (it does make a difference)
* run amp power cable on one side of vehicle and all signal and RCA cables on the opposite side
* make sure the grounding cable for the amp is as short as posible
* make sure the grounding cable for the amp is the same size or larger than the amp power cable
* check the resistance between all your grounding points, make sure there is not a big difference between them
* re-enforce the main battery ground with a larger gauge grounding cable
that's all I can think of rightnow, but try these and let me know if it works. Good luck.
HotlantaMDX,
Thanks for the info! I did try each one of these things (several times!) before resorting to the ground loop isolator. Nothing worked. I even tried grounding the head unit to the same place the amp is ground to - it made absolutely no difference. I just couldn't figure it out. I bought the highest quality wires and cables I could find. I kept the power wire away from the RCA's and speaker wire. Nothing worked. It sounded like a dentist's drill in my new $40,000 vehicle!
Of course, there *is* a ground problem somewhere that I created, otherwise the problem would not exist. But I just got sick looking for it after two days (probably 12 hours worth) of trying everything!
I do think, however, that the problem was aggravated by the fact that I ran new speaker wire to all the speakers. There was one other person on this forum that did the exact same type of installation as me EXCEPT he didn't run new speaker wire. He used the speaker wire from the factory harness, and he experienced zero noise. If I took the negative side of the speaker wire and ground it to the chassis, the noise was greatly reduced but still noticeable. So I believe the new wire does somehow play a part... |
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| wlmdx |
| The whine disappeared after I ran the power cable on one side of the vehicle and the RCA and speaker cables on the opposite side. However, I am still expriencing the buzz(sounds like air leaking). I get the signal from the OEM Bose amp. Has anyone try to get the signal directly from the Bose head unit?? It seems that the Bose amp is not sending clear signal out of it. Has anyone try this site www.linkmeup.com? They sell products such as connectors...etc that you can upgrade the Bose system without changing the head unit. How to avoid the "boom" from the sub when turning off the car? I tried to low the volume before turning off the car, didn't help. |
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