Am I Wasting My Time.

[DaveO74]

I am currently undertaking a big overhaul of my 33 GTST and part of that has been adding a new interior. While I had everything out I decided I may as well do all the soundproofing I have read so much about and well......went a little crazy and have pretty much covered every space I can think of within the cabin including the roof lining and behing the back seat.

The only thing is I have mostly used 10mm closed cell sound proofing foam (Except for the front doors which has both foad and proper dynamat)and this has been glued onto the car using contact adhesive so it will NOT come off IMO.

Some pics so you can see what I am talking about

Now I am at the stage of cleaning up the boot and decised to line it in the foam as well because believe it or not it actuall does kill off a LOT of road noise.

My mrs reminded my that I have two 12" subs in a box in our spare room which although almost brand new have been sitting around for about 7 years. They are nothing special but I thought they would add an extra bit of bass/low down sound if I was to throw them in the boot (With extra amp of course)

As I am really not that well educated with car stereo stuff could the knowledgeable people around here please advise me as to wether I am wasting my time because of all the extra soond proofing between the boot and the cabin (back seat area)puuting the subs in the boot. Will I actually be able to hear them or have I sound proofed myself into a corner so to speak.

Thanks

D

[GTRPowa]

I'd be inclined to sound proof the whole boot (if weight isn't a question) and leave between the boot and cabin. In some areas of high panel resonance I'd heard of people slicking weights to the resonating area with a strong 3M tape to change the resonant frequency to something that isn't as affected by road noise. Dunno if it works but, haven't seen any true test results.

[DaveO74]

Thanks mate but that's the problem, the area between the cabin and the boot is already soundproofed and the foam has been stuck on to the bit behind the back seat with contact adhesive.....bloody strong stuff that will never let go.

Im just unsure wether I have blocked out too much of noise that will come from the boot to make the subs usefull

[Chris Rogers]

I can tell you that you have done a good job of it. that siad IF you can get the foam off - do so. if not - pull the rear speakers out. that will help things to a point.

[GTRPowa]

A heat gun will remove anything

Then eucalyptus will remove the sticky crap.

However there is no harm in trying it out how you have it. - I've always wondered if you'd get superior bass (SPL wise) if you had the box mounted deep in the boot, subs facing backwards in a ported box with ports tuned to come through the parcel shelf. Doo it

Only way you'd truly know (again SPL wise) would have been doing a road test with sound proofing everywhere cept between cab and boot, with a dB meter. Then testing again WITH proofing between can and boot. I like how thorough you've been, the mid and top end should sound great. Get road tyres that focus on low noise as well?

Edited March 12, 2011 by GTRPowa

[DaveO74]

I can tell you that you have done a good job of it. that siad IF you can get the foam off - do so. if not - pull the rear speakers out. that will help things to a point.

Thanks for the kind words I was wondering wether I overdid it as I was kind of winging it!!

Correct me if I'm wrong cause I am in no way well educated with car sound but wouldn't removing the rears kind of make things sound uneven?

Maybe I'll just chuck the box in and see how it goes, no biggy as I have it here anyway and it does have two of the port thingys built in. I might be able to rig something up to get the ports comming out at the parcel tray what do you think?

GTRPowa, forgot to mention earlier when you mentioned soundproofing the boot as well, I will definately be doing it. That's the good thing about the foam, it ways bugger all. I bought around 7metres of the 10mm and 5.5m of the 5mm and all up it widths less than 5kg. For example the two front doors in the proper stuff is heavier that the entire car lined in foam including a second layer inside the front doors.

[GTR-N1]

That's the good thing about the foam, it ways bugger all. I bought around 7metres of the 10mm and 5.5m of the 5mm and all up it widths less than 5kg.

...and can't hear screams coming from the boot (whilst disposing of wife who should have reminded you earlier about spare 12" subs)???

[DaveO74]

...and can't hear screams coming from the boot (whilst disposing of wife who should have reminded you earlier about spare 12" subs)???

Hahaha, exactly Terry.

I forgot all about the subs it's been so long. I've done such a good job of keeping the car noise out of the cabin that I dunno wether I want to go backwards for the sake of a bit of bass that will ultimately produce rattles and vibrations????

Maybe I should just pit some good 6x9's in the back for the extra bass

[boiracer]

I did exactly what your doing now to my Beetle yrs ago. it made a huge difference in sound and heat inside the car (external oil coolers and thermos under the back parcel shelf and solid mounted engine and gearbox). it made it almost bearable in daily use.

go the subs, and leave some nice 6's in the back. 6x9's are over rated. and aparently a bit of a squeeze in a liner without making a whole new shelf or spacers etc.(don't cut the parcel shelf itself)

Edited March 13, 2011 by boiracer

[Carbon 34]

a sound proof car is fine, bass is non directional below certain freq. you will still feel it shake the car, you can vent it it behind the rear guards between the boot and rear seat sides, if your creative. or remove the rear speakers and replace the grills again. then you will hear it fine. my car is even more soundproof then that ,

I moved my rear speakers mids and tweeters over and ported (tuned properly)the bass thru the factory holes right from the sub box. so if your creative you can do it with ease. notice the rear deck is now fiberglass molding of a factory one then modified . but no metal was cut in the car for any of the system. so not defectable !!!

6x9s suck, and cutting the holes is a structual defect !!!

[MOBASS]

Dave074

What you have done is looking good.

It is not overkill; I have done way more deadening on our 33 than you did.

I would highly recommend removing the oval shape panel behind the back seat, there is a huge difference to the amount of sound that you can get out of the boot :-)

I have seen a few people mount 6x9’s in the back but remember do not cut the rear panel. Also if you are going to mount the subs in the boot give the 6x9’s a miss. A set of 6 inch will be more than enough for rear fill.

90% of the time I do not have rear speakers in at all, now that I have to get the baby seat in the back they are pretty much only in at shows.

Anyway keep up the good work

Simon