Need your help/opinion

[Ex-Rolla]

Hello everyone!

I have a bit of a problem and it's driving me nuts trying to figure it out. I had my system installed at a shop a while back... cheap price + me being lazy = get someone else to do it. Long story short, i was never really happy with the install (you get what you pay for) because of the constant buzzing of engine noise...

Anyway, today i ripped everything out and decided to do it myself. Really crappy install by the shop, speaker wire and amp/trigger all run together, which is what normally generates the engine noise. I have some experience with this stuff, because i have installed a system in my previous 2 cars along with a couple of friends cars. Anyway, i purchased a really nice 4 channel LOC, 12 gauge speaker wire and a couple of well insulated RCA cables all from Elemental Design. I installed everytihng today, re-grounded the amps properly, ensuring no Power/speaker/RCA wires come into contact with each other. Start the car up and the engine noise is even worse :flaming.

So here is my question... Where did you guys place your LOC. I have mine located right beneath the deck where you would normall have the tape player connected. I can't think of anything else that can cause the problem besides the placement of the LOC and i'm not prepared to take the panels apart and start rewiriing everything.

Any input/suggestions you guys may have would be appreciated!!! thanks!:)

[MPS]

ground ur RCA to ur head unit see if that helps

if not ur amp may be bad or you still have a bad ground some where in ur car

[TheProfessor]

I put my LOC in the pocket above the head unit (where the Nav unit would go). I wanted to keep it somewhere close to the deck and the space was perfect.

[Ex-Rolla]

I repositioned the LOC to where you have it Prof, and no change. I guess it is a bad connection/ground. I don't think it's the amp because the problem is heard from my subs along with my mids/hi's. I have a seperate sub amp which has been working perfectly from when i purchased it 3 years ago.

The only wire i was unable to re-run was the trigger wire. It coulb be the one that is causing a problem. I think the original installer tapped into another accessory wire from somewhere under the dash, and not the one that should be used from behind the head unit.

In terms of Grounding the amps, i have both amps going into a distr. block with 8awg, then from there, using 4awg, to the post where the rear seat bolts to the car. That should be ok for a gfround point correct? I shaved the area of paint to ensure a proper contact.

any other suggestions are welcome. :)

[TheProfessor]

Everything sounds like it's done properly.

[Ex-Rolla]

Alrighty...

Tried a couple of different things today... I ran RCA's an old set of RCA's i had lying around from the LOC directly to the amp, without running them through the panels on the right side. I also tapped into the yellow wire with grey dots used for the acc. turn on, replacing the one that is currently run, straight to one of my amps... Still the same problem, which tells me it's not the RCA's or the trigger wire.

Soooooo, not much else i can think of. I'm going to re-ground everything again to a location in the trunk, away from the cabin. I'm thinking that my ground is too close to the actual amps, which could be contributing to the noise.

Also, my amps were originally screwed directly to the back of the seat, so i was thinking this was causing a ground loop. I placed 3/4 inch MDF underneath each amp, ensuring the screws used to secure the amp do not touch and metal, but that didn't seem to work either.

More ideas are always welcome...


LOCKDOWN - If you don't mind sharing... where do you guys normally run the power/trigger and speaker/RCA's in the mazda 3?

[TheProfessor]

If it makes a difference, I ran power and remote turn on wiring down the driver side of the car while speaker and RCA wiring went down the passenger side. The amp is mounted to a 3/4" MDF board and that is in turn mounted under the rear decklid (sedan). The ground wire is run from there to the passenger side of the trunk.

I followed this same process for each of our two MZ3's and neither have any noise issues.

[Ex-Rolla]

If it makes a difference, I ran power and remote turn on wiring down the driver side of the car while speaker and RCA wiring went down the passenger side. The amp is mounted to a 3/4" MDF board and that is in turn mounted under the rear decklid (sedan). The ground wire is run from there to the passenger side of the trunk.

I followed this same process for each of our two MZ3's and neither have any noise issues.


Thanks for the info... i know it's something i am overlooking. I'm probably going to mount the amps somewhere in the trunk, then ground them in another location.

thanks again Prof

[TheProfessor]

No need to thank me, I don't think I really helped. Let us know how it turns out.

[skunk2]

you can also try to run 1 amp at a time to try and isolate what maybe causing the noise.

[Ex-Rolla]

Instead of starting a new thread, i'll ask it here...

has anyone though of using RG6 or RG59 with and RCA adapter to run RCA's in the car? i know they're not as flexible and normal RCA's, but they are also much better insulated and if combined with really good connectors, the sheilding on them is much better than those "stinger" type cables.

I have access to a lot of coax, so as a time/money saver, this could be a good option... just want to hear what everyone thinks.

below is a link of the connector i'm referring to.
http://www.national-tech.com/specs/30r4-0100rd.htm

[skunk2]

if i remember correctly RG59 is not stranded....chances are they will break easier in mobile audio applications. i think this is why they are not as flexible as well. quality microphone cables make a better choice if you need custom length RCAs.

[Ex-Rolla]

if i remember correctly RG59 is not stranded....chances are they will break easier in mobile audio applications. i think this is why they are not as flexible as well. quality microphone cables make a better choice if you need custom length RCAs.


Thanks for the input skunk2

I'm going to pass by the source and see how much the connectors are... i have all the crimping tools and I spools of the cable lying around collecting dust, so i may just give it a try and see how it turns out. Many new homes that are prewired for component/audio cables are using RG6 nowadays, so it may be worthwhile to try it out. Especially considering i'm still getting the engine noise :(

btw... RG59 is stranded (more flexible, less insulated), RG6 is solid (not as flexible, usually double sheilded)...

[skunk2]

ahh so it is the rg6 that's solid...good luck!

[queens49]

Thanks for the input skunk2

I'm going to pass by the source and see how much the connectors are... i have all the crimping tools and I spools of the cable lying around collecting dust, so i may just give it a try and see how it turns out. Many new homes that are prewired for component/audio cables are using RG6 nowadays, so it may be worthwhile to try it out. Especially considering i'm still getting the engine noise :(

btw... RG59 is stranded (more flexible, less insulated), RG6 is solid (not as flexible, usually double sheilded)...

You sure about RG59 being stranded? RG59 and RG6 are both solid conductors, they are just used for different applications. RG59 is more flexible than RG6 because the conductor and insulation are thinner.

[Ex-Rolla]

You sure about RG59 being stranded? RG59 and RG6 are both solid conductors, they are just used for different applications. RG59 is more flexible than RG6 because the conductor and insulation are thinner.

you're right in most cases they are both solid... RG6 having a thicker gauge copper... I have seen RG59 using stranded wire for specialty installs where flexibility is extremely important. not common, but can be bought. (i work for a cable company so i have physically seen them).