Components installed: But

[Ben B]

I've installed my components, wired it all up to my amp, and wow! What a difference! Really good vivid sound!

So then I reassemble the entire car!, go to drive it back in the garage, and...

weeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

most annoying noise in the world that changes pitch with the engine revs!!!

What's causing this? I can't listen to the stereo with the engine on!!

Something easy to fix? or is it down to the wire placement? Didn't have this trouble when the amp was only running the sub!

(Amp is 4 ch- 1 & 2 are the fronts, 3 & 4 are bridged for the sub. Crossovers mounted in fusebox and above glovebox. Cables inside the plastic footplate bits)

 

[DanZ]

I had this, its a dodgy earth. Ground feedback loop, caused by a bad contact somewhere. Mine just went away by itself though! I think the contact 'bedded' itself in. Hope this helps.

 

[Tom]

First thing to do is make sure the amps earth is REALLY good.

 

[Ben B]

OK I'll check this tomorrow. Cheers.

Just strange it didn't do it when it was only amping the sub!

Thanks

 

[Tom]

Are you using the crossover in the amp for the aub?

 

[LightWarrior]

where is good to earth a sub? with a .5m cable its really hard to find somewhere!

Buzz
the poster formerly known as LightWarrior

 

[Tom]

Sub amp I hope

Just find a solid sounding bit of metal and make sure you sand it down to shiney metal and use a bigass bolt and a washer to get lots of pressure on the terminal. Don't be tempted to try and stick bare wires under a washer as it won't hold very well.

My system is actually earthed to one of the rear seat hinges.

 

[Ben B]

Yeah, The amp's crossover sorts out the sub. Just a matter of setting it all right now! Too many knobs and settings! Levels, High-pass filter, low-pass filter etc! Any tips on how to best set up the amp?!
Think I'll set the front comp's crossovers to -6dB on the tweeters. It's reallt reble-heavy at the mo

 

[Ben B]

I've just moved my earth point to one of the rear seat hinges, where it bolts down to the floor of the car. I sanded the metal down first, used a fresh clean washer to sandwich it in with, and even checked the gound connection on the amp itself.

No difference. What else could it be?

Is this down to the alternator or something?

 

[ashley h]

alternater noise.

hi, the reason it is doing this is beacuse the power leads connecting to the battery pick up noise from the alternater, this is why it changes pitch with revs etc.., to stop it: Run the phono leads from the head unit down a different side of the car than the power cabling, if this doesnt work buy a ground loop isolator(5quid from maplin) and plug it in just before the amp, this should sort it, if it doesnt, i think you'll need to get a different amp.

 

[Anonymous]

Re: alternater noise.

Putting the phono leads down the other side to the power is a myth

I would go straight for a ground loop isolator.

Ive seen them in halfords, no doubt more expensive, but the time you pay for postage (if you do not have a local maplins), it may be about the same price...

Daz

 

[Tom]

Re: alternater noise.

Ben, what head unit have you got?

 

[Ben B]

Re: alternater noise.

Sorry Daz, Hate to say it but you're wrong, that's actually cured it!! Thanks Ashley!

I had some excess power & RCA leads actually coiled around together under the back seat!! Stupid me! Undoing the coil instrantly improved the sound a bit, then running the cables down opposite sides of the car sorted out the rest! It now sounds crystal clear!

(It's a Blaupunkt MP52 HU, cheap Maystar QX amp & sub I'm affraid (nothing award winning, but it gives the sound the extra body I'm after, and now MB Quart components)

 

[Anonymous]

Re: alternater noise.

Try telling the people on the talk audio forum that...

You maybe right, but you may have a had a loose connection...

Glad you got it sorted anyway...thats the main thing

Daz

 

[Tom]

Re: alternater noise.

Loose connection or most likely just cheap cables.

 

[Ben B]

Re: alternater noise.

Actually Daz- you were right!

The really loud blindingly obvious squeel was sorted by running the cables down different sides, but I've just been for a drive, and noticed there is still a background squeel going on. So I drove straight to Halfords and bought an interferance suppressor!

 

[Anonymous]

Re: alternater noise.



Daz

 

[Ash]

Re: alternater noise.

for some reason the ground loop is all ways between the rca sub out and sub amp, not between the front and back rca's/amps.

i found improving the earth between the battery and bodywork(adding second cable) makes the sound clearer too on big juicy systems.

 

[Tom]

Re: alternater noise.

There are several upgrades to the electrical system you can do.

 

[DanZ]

Re: alternater noise.

Ash when you say "clearer", do you mean the mids and highs are further defined? or does it get louder? not sure what you mean...what benefit would adding a 0gauge earth from my -VE battery terminal to the chassis give?

Tom what kind of 'upgrades' can I do to further improve the sound of my setup apart from the obvious? (i.e. sound deadening, correct set-up of amps, positioning of everything).

Here's my setup:
Vibe CBR12 Active Sub (built in Vibe amp)
Vibe QB69s on stealth shelf
Focal K2 front components
Audiobahn A6004T amp runs QB69s and K2s
Voodoo 1.2 farad capacitor (square)
All connected via a Lanzar 0gauge wiring kit