Road noise coming through sub???

[Pullstarter]

Hey All,
Just had a 12" boxed sub installed in my MK6 GTI running it in the boot. When the stereo is turned off i'm getting booming coming thru the sub when I go over bumps. When the stereo is on the problem goes away. I was thinking this could be due to the cover over the spare being very thin and hard, maybe the road noise is being transmitted through the body of the boot floor to the sub? Going to try putting some 10mm foam under the carpet and see if that helps. Any suggestions welcome.

Cheers
Simon

[noone]

If it were a physical transmission it would happen when the system is on. I'd be checking the earthing of the amp and wiring from head unit. Is the amp off when the head unit is turned off?

[Pullstarter]

Yes amp turns off when head unit is turned off I checked that.

[MCiN7]

When the stereo is turned off i'm getting booming coming thru the sub when I go over bumps.

Can you explain the booming noise more?

[Idle]

Sharp movements causing the speaker to vibrate? A bit of foam under it might well help.

[Pullstarter]

It sounds like base beats from a song when i go over bumps or uneven ground, not loud but it's clearly audible. I'd be surprised if its an electrical issue as I've had many installs done by these guys before with no issues although It's possible I guess. Will try to put some foam in this arvo and see what happens.

[Pullstarter]

On closer inspection it appears that the amp is actually still getting power and "on" when the deck is turned off. I assume this is causing the problem? When the deck is turned off it seems the slightest vibration is going right through the sub. As soon as the head unit is turned back on the sound goes away. Mighty pissed that the install wasn't done properly I can assure you!

[MCiN7]

If the amp is still on when the unit is turned off, they tapped into the wrong accessories cable

For example in Golf 4's you have ~3 options
key turned to ignition position {12v cuts out after turning to -'auxiliary' position}
key turned to ignition but continues to send 12v until key is completely pulled out of the ignition
key turned on to ignition but continues to send 12v until key is completely pulled out of the ignition AND until door is opened

I'm sure there's more options in MK6's but you want them to tap into the accessories cable that switches on and off with the unit (at the back on the unit..) and run a cable to the amplifier.

[Pullstarter]

Apparently these head units don't have a remote on/off cable that's why they wired it the way they did. I'm simply going to put an in-line on/off switch in the cable they've hooked up to (which is easy to get at at least) and all should be okay.

If the amp is still on when the unit is turned off, they tapped into the wrong accessories cable

For example in Golf 4's you have ~3 options
key turned to ignition position {12v cuts out after turning to -'auxiliary' position}
key turned to ignition but continues to send 12v until key is completely pulled out of the ignition
key turned on to ignition but continues to send 12v until key is completely pulled out of the ignition AND until door is opened

I'm sure there's more options in MK6's but you want them to tap into the accessories cable that switches on and off with the unit (at the back on the unit..) and run a cable to the amplifier.

[MCiN7]

Good thread on Vortex that will help you (other people with the same issue)
VWVortex.com - Mk6 stereo wiring diagram

"Here's how the harness looked after cleaning up. The blue leads are going to be used for the turn on lead which you will have to grab at the cig lighter in the center console."

http://forums.vwvortex.com/showthread.php?5646053-MKVI-Audio-Upgrade-DIY

[Pullstarter]

Cheers for all the info guys. In-line on/off switch added and problem solved Thanks again