Engine noise problem

[Dafaseles]

Maybe someone can shed light upon this for me.
Recently removing a system in a truck. I removed the subwoofers, RCA's, and amplifiers. Door speakers and the wiring where still in. When we took a drive to the hardware store, the engine noise was still present through the speakers. Noise changes pitch with RPMs. Since removing all the speaker wire and speakers, obviously it's now gone.
How could the engine noise still be present with the speakers not hooked up to anything? Is this going to be a problem when we install the new system? Even if we're using all new grounding points for the amplifiers? Any idea how this could happen and in the future be prevented?

Click to read more...

 

[audiobaun 5,000+ posts]

Did you change the HU also? If so, ..What brand is it?? Pioneer?If so, what model? Could be the HU

 

[RobGMN 5,000+ posts]

Maybe someone can shed light upon this for me.
Recently removing a system in a truck. I removed the subwoofers, RCA's, and amplifiers. Door speakers and the wiring where still in. When we took a drive to the hardware store, the engine noise was still present through the speakers. Noise changes pitch with RPMs. Since removing all the speaker wire and speakers, obviously it's now gone.
How could the engine noise still be present with the speakers not hooked up to anything? Is this going to be a problem when we install the new system? Even if we're using all new grounding points for the amplifiers? Any idea how this could happen and in the future be prevented?

Inductive pickup, kind of like how phones can be charged without physical contact of the wires, or a neon light can be energized by a tesla coil.

Trace the wiring paths you used before. You may have had the speaker wire running alongside other wires and they were picking up "noise", which can actually move speaker cones even if the wires are ONLY connected to the speaker and not an amp or HU.
When possible, cross all wires at 90 degree to each other and avoid running wires parallel and close to each other.

 

[audiobaun 5,000+ posts]

Big 3 would help quite a bit.. Two solid ground points for the motor and at the frame of the truck should knock out any issues along with increasing and maintaining voltage from the alt to battery

 

[Dafaseles]

Did you change the HU also? If so, ..What brand is it?? Pioneer?If so, what model? Could be the HU

The head unit was an older, higher end model pioneer double din. Thing was so old though, we couldn't tell you the model. Maybe 6-7-8 years old. That's been changed since. Just seemed weird because nothing was connected to the head unit.
Big 3 was done with 1/0 OFC JL cable. That's been ripped out also. Upgrading all the wiring as well.

 

[Dafaseles]

Inductive pickup, kind of like how phones can be charged without physical contact of the wires, or a neon light can be energized by a tesla coil.

Trace the wiring paths you used before. You may have had the speaker wire running alongside other wires and they were picking up "noise", which can actually move speaker cones even if the wires are ONLY connected to the speaker and not an amp or HU.
When possible, cross all wires at 90 degree to each other and avoid running wires parallel and close to each other.

So, I get all that. And absolutely makes perfect sense. The only thing is everything else other than the speaker wire was removed. No cables, no RCA's, no ends of speaker wire touching bare metal. I guess there is that chance that maybe the speaker wire at some point was damaged and bare, but when we removed all of it from the truck, I didn't come across any damaged speaker wire, though I wasn't tentatively looking for it either.
Everything has since come out of the vehicle, it will get new speakers and speaker wire, new subs, new RCA's, new grounding points with new cable, new head unit, new alternator, everything. So hopefully that problem doesn't persist with the new install. I just found it rather strange getting engine noise when nothing is hooked up to anything, and the usual suspects for causing such noise had been removed.

 

[audiobaun 5,000+ posts]

The head unit was an older, higher end model pioneer double din. That's been changed since. Just seemed weird because nothing was connected to the head unit.
Big 3 was done with 1/0 OFC JL cable. That's been ripped out also. Upgrading all the wiring as well.

Ive ran JL, Kicker , KNU Concepts and other Power wiring, and Made my Own Big 3 kits. After about two years those brands began to Oxidize and needed to be cut back to refresh the copper with new lugs.Ive since replaced with Sky High 1-0 Awg OFC and havent had any issues for the last two years thus far. Ripped out that Cadence CCA like 10+ years ago after finding out its garbage and reading about wiring, and I havent changed my Sig in years

 

[audiobaun 5,000+ posts]

So, I get all that. And absolutely makes perfect sense. The only thing is everything else other than the speaker wire was removed. No cables, no RCA's, no ends of speaker wire touching bare metal. I guess there is that chance that maybe the speaker wire at some point was damaged and bare, but when we removed all of it from the truck, I didn't come across any damaged speaker wire, though I wasn't tentatively looking for it either.
Everything has since come out of the vehicle, it will get new speakers and speaker wire, new subs, new RCA's, new grounding points with new cable, new head unit, new alternator, everything. So hopefully that problem doesn't persist with the new install. I just found it rather strange getting engine noise when nothing is hooked up to anything, and the usual suspects for causing such noise had been removed.

Was the older Pioneer HU still installed?? If So.. Ill bet that the PICO fuse may be blown in it.Thats an annoying problem with Pioneer HUs. I dont Buy Pioneer HUs just because of that alone.. and I swapp amps all the time/ test them out in my truck or run one for a month and swapp to another. It can be repaired.You can get a computer shop to do it for like $20-50 bucks if you still want to keep it , or if you are handy with a solder gun and have a little patience, you can do it yourself. instructions on You Tube with Vid.But New HUs are fairly cheap for a decent 4-5volt unit for Kenwoods or JVC/same Co. Like $150-300 bucks depending on Model and features.. Sony 5 volt with like 3 yr warranty I believe. HUs are getting slim as the Computer chip shortage is slamming the industry at the moment raising prices.But Shop around.Sonic Electronix and Crutchfield generally will have a wiring harness and sometimes a dash kit included depending on the vehicle and HU chosen.

 

[audiobaun 5,000+ posts]

I just picked up an old BNIB Alpine CDA 9885 HU from a Local for like $200 bucks. Has all I need on it

 

[RobGMN 5,000+ posts]

So, I get all that. And absolutely makes perfect sense. The only thing is everything else other than the speaker wire was removed. No cables, no RCA's, no ends of speaker wire touching bare metal. I guess there is that chance that maybe the speaker wire at some point was damaged and bare, but when we removed all of it from the truck, I didn't come across any damaged speaker wire, though I wasn't tentatively looking for it either.
Everything has since come out of the vehicle, it will get new speakers and speaker wire, new subs, new RCA's, new grounding points with new cable, new head unit, new alternator, everything. So hopefully that problem doesn't persist with the new install. I just found it rather strange getting engine noise when nothing is hooked up to anything, and the usual suspects for causing such noise had been removed.

Induction doesn't require contact. Think of the wire as an "antenna" that is taking the nearby electron flow and turning into actual A/C on the wire, which is driving the speaker (speakers make sound with A/C current).
Given you experienced the problem without anything but the speaker wire connected, it might be a good idea to do the install by installing just those items first. If you hear noise, work on eliminating it before going any further.

 

[Dafaseles]

Ive ran JL, Kicker , KNU Concepts and other Power wiring, and Made my Own Big 3 kits. After about two years those brands began to Oxidize and needed to be cut back to refresh the copper with new lugs.Ive since replaced with Sky High 1-0 Awg OFC and havent had any issues for the last two years thus far. Ripped out that Cadence CCA like 10+ years ago after finding out its garbage and reading about wiring, and I havent changed my Sig in years

The old head unit was still installed at the time. But there weren't any RCA's connected or speaker wire. Not saying it couldn't happen, but how did that crappy signal get into the speakers?
Yeah, we're upgrading all the cable. Planning on overdoing everything since it'll be a kind of high wattage system. Figured it would be best just to go with everything new rather than reuse any of the old system. Good or not.
Just wish I knew for sure why I was getting that signal in order to make sure it doesn't happen again

 

[Dafaseles]

Induction doesn't require contact. Think of the wire as an "antenna" that is taking the nearby electron flow and turning into actual A/C on the wire, which is driving the speaker (speakers make sound with A/C current).
Given you experienced the problem without anything but the speaker wire connected, it might be a good idea to do the install by installing just those items first. If you hear noise, work on eliminating it before going any further.

That's a good idea. I didn't think about that.
So even though the speakers weren't hooked up to anything, that "noise" could still be coming from the head unit or crappy grounding, then picked up through the speakers? Just the electrical signal finding any path or possibly can to travel? Possibly through the door sheet metal or something along those lines?

 

[RobGMN 5,000+ posts]

That's a good idea. I didn't think about that.
So even though the speakers weren't hooked up to anything, that "noise" could still be coming from the head unit or crappy grounding, then picked up through the speakers? Just the electrical signal finding any path or possibly can to travel? Possibly through the door sheet metal or something along those lines?

No. it's coming from the wires themselves. Nearby electrical impulse is picked up by the speaker wire and becomes it's own electrical impulse, which then moves the speakers that are only connected to the speaker wires.
This is not the exact same phenomenon, but you'll get the gist of it: https://en.wikipedia.org/wiki/Inductive_charging

 

[YourNameHere 10+ year member]

No. it's coming from the wires themselves. Nearby electrical impulse is picked up by the speaker wire and becomes it's own electrical impulse, which then moves the speakers that are only connected to the speaker wires.
This is not the exact same phenomenon, but you'll get the gist of it: https://en.wikipedia.org/wiki/Inductive_charging

Thats all BS! its a ground issue, ground HU straight to battery and call it a day

 

[Dafaseles]

No. it's coming from the wires themselves. Nearby electrical impulse is picked up by the speaker wire and becomes it's own electrical impulse, which then moves the speakers that are only connected to the speaker wires.
This is not the exact same phenomenon, but you'll get the gist of it: https://en.wikipedia.org/wiki/Inductive_charging

So, just to make sure I have this correct for my own knowledge.
Basically, that noise is coming from somewhere, and like you said, the speaker wire is just picking it up like an antenna. It could still be a bad ground or from the head unit.