# Amp Install Ground Points / Mounting Locations



## alpha_omega (Nov 12, 2006)

So I am getting a new car. Was able to snag the radio, amp, and sub out of the old car. Im obviously going to redo the wiring in the car, so I wanted to ask... on a Mk4 GTI, what, if anywhere, is the best place to ground the amp? It'll be somewhere in the trunkspace, so anywhere around there is ideal. My last car I had, I just took a file/sand paper and ground down a spot under the rear trunk mat to bare metal, drilled a small hole, and screwed the negative lead to that. However, given the opportunity to start fresh and do it right from the beginning, I wanted to see if there were better places in the trunks of Mk4 GTIs to mount the negative terminal to.

Additionally, Does anyone have suggestions on ways to mount an amp to the back of the Mk4 seats? I want to say I should be able to mount it via screws, but I am not sure. Id like to avoid mounting the amp to the sub box as I've been told that changes the acoustical properties of the box (sealed 12x12x14 enclosure for 10 boston acoustics sub)

Any and all insight into both of the above listed issues would be MUCH appreciated!

Thanks!


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## mahoneybags21 (Oct 12, 2009)

All you need to know will be in this DIY for an amp/sub install

http://forums.vwvortex.com/showthre...et-Amp-Sub(s)-Install-Guide&highlight=monsoon


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## alpha_omega (Nov 12, 2006)

mahoneybags21 said:


> All you need to know will be in this DIY for an amp/sub install
> 
> http://forums.vwvortex.com/showthre...et-Amp-Sub(s)-Install-Guide&highlight=monsoon


I saw that, and while that would work, I was looking for something a little more hidden. Im trying to do a real clean install and minimize the amount of exposed wires. As such, are there any more hidden locations?

it also doesn't touch on my second question regarding how to mount the amp to the back of the seats or any ideal places to mount it.


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## NFrazier (Jul 22, 2006)

alpha_omega said:


> I saw that, and while that would work, I was looking for something a little more hidden. Im trying to do a real clean install and minimize the amount of exposed wires. As such, are there any more hidden locations?
> 
> it also doesn't touch on my second question regarding how to mount the amp to the back of the seats or any ideal places to mount it.


Anywhere around the spare tire well pretty much. It all depends on where you plan on mounting the amplifier. 

If you are talented and adventurous you can ground it to a 10mm bolt that is used to attach the cd change bracket to the body of the car.


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## B.A.S.S. (May 14, 2009)

Or to one of the brackets holding the back seat down or seatbelt mounting bracket. You'll just have to drill out the ring for the ground terminal


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## alpha_omega (Nov 12, 2006)

Thanks for the ideas. I think I may know of a way to ground it properly while hiding the cabling. I may try to get it behind the carpeting on the sides of the trunk and run it over to the the monsoon amp bracket or try to sneak it behind the tie-down thing specified in that DIY thread. I just want the wiring to stay as hidden as possible. Trying to go for a show-quality install and this would be my first rodeo with such a job. Usually I just do it to get it done, but I wanted to do it better. Plus, Ill be installing a custom hardwood floor into the trunk of the car, so I gotta do the wiring just right so it works with the hardwood floor.


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## 2.GOlf (Aug 3, 2010)

I know I'm a bit late with this post, but since you are emphasized wanting a clean install, I thought I would post pics of my setup. I have the factory single DIN monsoon system with the CD changer in the trunk above the factory amp. I was able to stack my Polk Audio PA330 sub amp on top of the monsoon amp and still be able to close the access door in the trunk. This makes for the cleanest install there could be imo. I ran my power wire and remote wire up the driver's side of the car and grounded the amp to the 10mm CD changer bolt as NFrazier described. I used a line convertor I had laying around for the amp signal. I hid the speaker wire under the trunk mat and routed it into my backseat to feed my 8" Polk sub. The sub enclosure is bungeed to the child seat anchors in my backseat so I can remove it if I need to. This conservative setup won't rattle windows from two blocks away, but I get a good, satisfying thump. Good luck with your install.


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## NFrazier (Jul 22, 2006)

2.GOlf said:


> I know I'm a bit late with this post, but since you are emphasized wanting a clean install, I thought I would post pics of my setup. I have the factory single DIN monsoon system with the CD changer in the trunk above the factory amp. I was able to stack my Polk Audio PA330 sub amp on top of the monsoon amp and still be able to close the access door in the trunk. This makes for the cleanest install there could be imo. I ran my power wire and remote wire up the driver's side of the car and grounded the amp to the 10mm CD changer bolt as NFrazier described. I used a line convertor I had laying around for the amp signal. I hid the speaker wire under the trunk mat and routed it into my backseat to feed my 8" Polk sub. The sub enclosure is bungeed to the child seat anchors in my backseat so I can remove it if I need to. This conservative setup won't rattle windows from two blocks away, but I get a good, satisfying thump. Good luck with your install.


 :banghead::what:


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## Pat @ Pitt Soundworks (Nov 14, 2008)

You do not want your sub in a box sitting on the back seat. If you get in to an accident, you can count on that thing killing you.


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## phd-12v (Jun 13, 2001)

OMG wire nuts.....................if there is anything i hate more than t-taps, is friggin wire nuts.:banghead::banghead::banghead::facepalm::facepalm:


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## 2.GOlf (Aug 3, 2010)

Wow, tough crowd tonight. Relax on the wire nuts. I haven't gotten around to soldering my connections yet. Its a work in progress that I literally just got working last week. I'll be honest, I had not considered the safety sacrifices of a backseat enclosure. However, I would consider it highly unlikely that a even a 50g impact would break the high strength rubber bungee I used. Not to mention the elasticity of the bungee would spread the force of impact over a distance, just like the crumple zones engineered into our cars. I posted these pics primarily to show that with a little creativity, there is room enough for another amp in the factory trunk location.


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## NFrazier (Jul 22, 2006)

2.GOlf said:


> Wow, tough crowd tonight. Relax on the wire nuts. I haven't gotten around to soldering my connections yet. Its a work in progress that I literally just got working last week. I'll be honest, I had not considered the safety sacrifices of a backseat enclosure. However, I would consider it highly unlikely that a even a 50g impact would break the high strength rubber bungee I used. Not to mention the elasticity of the bungee would spread the force of impact over a distance, just like the crumple zones engineered into our cars. I posted these pics primarily to show that with a little creativity, there is room enough for another amp in the factory trunk location.


 The issue is in car accidents, things don't go left to right, up and down. I've seen people get into an accident at 5mph and have airbags deploy and things in cupholders go flying every which way. 

Go watch a crash test. **** goes where it wants to, especially given the weight of a subwoofer and mdf enclosure.


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## alpha_omega (Nov 12, 2006)

lets keep this on topic, k guys?  

but it I will see if I have enough room to mount the amp in there. I dont need the CD changer at all, but my concern is more centered around ventilation and keeping the amp cool. with a 1000watt amp, things can get kinda toasty. 

Are there any issues with mounting the amp to the back of the sub box, but using some poly stand-offs that will space the amp off the sub box for ventilation and put it somewhere convenient?


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## Pat @ Pitt Soundworks (Nov 14, 2008)

The amp is going to vibrate more from you driving the car than it is from the sub box. You don't need to "Stand off" an amp from it's mounting surface. The mosfets inside the amp are bolted to a part of the cover called the heat sink. Which part should be apparent (giant fins). If it doesn't have fins, then the entire cover of the amp is the heat sink.


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## alpha_omega (Nov 12, 2006)

the cover is definitely on giant heatsync. It has fins on either side to help disspate the heat. 

I think Im going to try for the cd changer area first. Since I won't need the changer, I can take that out and put the amp there, assuming it fits. We'll see. Just hope there's enough ventilation in that area to keep the amp cool.


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## 2.GOlf (Aug 3, 2010)

I have not yet tackled that ventilation problem. For now I just leave the access door unlatched and hanging open in my trunk, but my plan is to cut a shapely hole into it and fit some fine stainless steel grading over the hole. That way air should flow freely in and out. I haven't been too hot to do this (pun intended) since we are in the dead of a wisconsin winter right now and overheating my little 330 watt sub amp is the least of my worries.


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## iamshayan (Mar 27, 2009)

wow worst install ever... 
thats a good example of how NOT to install your amp and sub, never use wire nuts.
maybe its a clean install if your names red green
:banghead:


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## akrazyassho (Jul 18, 2010)

If your gonna do it do it right, here is my setup:

Its two polk audio amps (one for the speakers and one for the subs/sub) screwed into the back of the seat. Wires are run under the rear seat carpet, which arent flat so they give you room to run wires w/o poke.























































This is the sub setup, its a work in progress, 1 12" Alpine type R, firing downward (reverse mount) into a box thats about .58 cubic feet. The enclosure does need to be made bigger for this setup, I will makes it the proper size once we get a nice warm weekend. The right side is a storage area for anything, the whole setup is a false floor, w/ three pieces that can be removed to get to the spare and wheel tools.


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## alpha_omega (Nov 12, 2006)

while that looks awesome... it's not what im looking for. I need this setup to be versatile since I do use my GTI to haul larger items, like sets of wheels, larger car parts, etc. 

Does anyone know of any potential issues with just mounting the amp directly to the sub box? I really would like to be able to just pull the connections off the amp and remove the sub/amp so I can fit larger items in my GTI if need be.


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## John Reid (Jun 30, 2010)

No issues what so ever.

It won't change the acoustic properties of the box... all it'll do is make the box heavier.

If you stuck the amp INSIDE the box, yeah, THEN it would change the acoustic properties...


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## alpha_omega (Nov 12, 2006)

John Reid said:


> No issues what so ever.
> 
> It won't change the acoustic properties of the box... all it'll do is make the box heavier.
> 
> If you stuck the amp INSIDE the box, yeah, THEN it would change the acoustic properties...


hahahahah yeah. I dont think i'd even be able to get the amp inside the box anyways 

i was just thinking along the lines of the amp being mounted to the box affecting the acoustic properties since its a sealed enclosure... but i havent been able to find anything to support/deny it aside from what people have directly told me.

thanks for the info tho. Im just gonna go ahead and mount it to the box like I wanted to.


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## akrazyassho (Jul 18, 2010)

Mounting the amp to the box works but only if your not going to be moving the box. If you had to remove/move the box it would be a hassle to connect and disconnect the amp, also this makes it a lot easier to have your whole system stolen.

Looking at this thread some of theses people mounted their amp in the rear compartment. For your case I would say this is a better spot.

http://forums.vwvortex.com/showthread.php?5140647-Subwoofer-Amp-installed!&p=69999135#post69999135


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## alpha_omega (Nov 12, 2006)

akrazyassho said:


> Looking at this thread some of theses people mounted their amp in the rear compartment. For your case I would say this is a better spot.
> 
> http://forums.vwvortex.com/showthread.php?5140647-Subwoofer-Amp-installed!&p=69999135#post69999135


 I did that in my old car and while it worked great, i ran into issues where the screws i was trying to use wouldn't take into the back of the seat. plus, it doesn't allow me the full storage capabilities of the gti because i can't put things on top of the amp. 

by putting it "all in one" it makes it easier for me to pull out my system if i need to haul larger items. will it happen frequently? probably not, but im all for a solution that gets me the results i want while not limiting the usefulness of my car. Honestly, unscrewing 3 terminals on the amp to pull the unit out ins't much of an issue. remember, all I have is a 10" sub mounted into a standard 12x12x12 sealed enclosure so there's nothing custom to get in the way. 

and as far as "getting it stolen", i see no difference between mounting the amp to the back of the seat and mounting it to the sub box... sure, its easier with the latter of the two setups, but if they have already broken into your car, they'll very likely find a way to take your stuff regardless of where it's mounted.


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