Question for Stereo Guru's

[adventureduo]

How can i have engine noise coming from 1 speaker out of 5?

When we bought our SMB the loading door on the side speaker wasn't hooked up. The PO had cut the wires (maybe too loud in camp or maybe for this apparent engine noise) and i connected them back up. Now i get a engine noise from this speaker upon first starting the rig up really bad.. and it somewhat goes away after the rig is on the road for a while.

What causes this? bad ground on the speaker? bad speaker itself? I really want that speaker to function while in camp. All the rest of the speakers (2 upfront on the doors and 2 outback on rear ambulance doors) work just fine with no engine noise.

Your input is greatly appreciated..

 

[adventureduo]

Just one other thing. The speaker appears to be stock and the wiring is stock also. I have not modified anything. Previous owner just cut the wire and all i did was reconnect it.

 

[mountainpete]

If the noise stops when the engine is off, it's not the speaker itself. Odds are the speaker wiring is too close to a large power wire that is leaking RF.

Pete

 

[adventureduo]

Yeah it's fine with the truck off. Interesting, if thats the case.. then i'll leave it disconnected like the PO did cause there's no way im re-routing all the cabling through the walls of the van.

Maybe i'll just put a inline switch so i can run the speaker in camp without the truck running. hmm. Didn't think of that one. That way i can flip the switch off when i drive and dont have to hear a hum.

 

[tdesanto]

Odds are the speaker wiring is too close to a large power wire that is leaking RF.

Pete

This would be my guess too.

 

[spencyg]

I'd re-route the wires going to the speaker. If this isn't possible, than I'd replace the existing wire run with shielded wire (typically used in noisy automation equipment, etc). This should kill most of your noise issues. #1 choice would be re-routing.

Spence

 

[mountainpete]

There is one other long shot you can try. Get some ferrite and wrap it around the power wire that is close to the speaker wire. Place it between the power source and where the speaker and power wire come close. That *may* help.

Instead of going out and buying ferrite though, try and recycle some. Like all of us, you probably have some old power cords lying around the house and garage. Find one that has one of those plastic things clipped around the end - TVs and older computer equipment usually had them. Inside that clip is ferrite. Place it around the power wire and see if it helps.

Might not work, but if you have some ferrite it's worth a try.

Pete

 

[slomatt]

Where is the 5th speaker mounted in the truck? I'm late to the party in replying, but as others have said it could be cross-talk from a power wire. If you can find anywhere that the speaker wire runs parallel to a power wire you should re-route it to cross at as close to a 90 degree angle as possible. Also, if excess wire is bundled into a loop somewhere that can form a rudimentary antenna and pick up noise.

- Matt