GolfGTIforum.co.uk

General => Car audio => Topic started by: Gabber-Baby on 08 January 2008, 20:13

Title: Best place for small amount of Dynamat?
Post by: Gabber-Baby on 08 January 2008, 20:13
I haven't installed my sound system yet because I am still waiting on some fabric to be delivered.

I have :-

2x 12" Pioneer Subs, 400w RMS
JBL power amp with a power cap (approx 750w RMS depending on what omhage i use)
Sony Xplod Head Unit
2 x Sony Xplod 6x9's

(http://i239.photobucket.com/albums/ff10/gabber-baby/Image000.jpg)(http://i239.photobucket.com/albums/ff10/gabber-baby/Image014.jpg)

It's really only a basic budget setup but has still got quite a bit of power, the boyfriend got most of it for me and is also installing it soon. I have got 10 feet of Dynamat which i know is no where near enough for a proper boot build so i have to use it sparingly because it's so damn expensive. I just want to know if there are any typical places in a mk3 golf that are prone to rattling? I suppose it will be the same on any 10 year old car? Could be wrong. I was going to fit most of the dynamat in the boot itself, and behind the number plates so they don't vibrate.

Any better suggestions?
Title: Re: Best place for small amount of Dynamat?
Post by: Len on 08 January 2008, 20:19
Wouldnt waste it behind the number plate, get some good mastic for that.

Personally I would always start with the doors and the rear panel as yours is a 3 door.
Title: Re: Best place for small amount of Dynamat?
Post by: Heyho on 08 January 2008, 21:16
Usually it would be ideal in the front doors...but as you are concentrating your efforts in the boot, use it on the largest expanses of metal/panels in that area.

It's not really used to stop rattles, but to reduce and eliminate panel resonance by adding mass. 

Alternatively sell the powercap and 6x9s, deaden the front doors and put some nice components in there. :smiley:
Title: Re: Best place for small amount of Dynamat?
Post by: Uruk Hai on 08 January 2008, 21:40
If you dont want to blow shed loads on dynaprat then you could try this :-

 http://www.wickes.co.uk/invt/243009

does the same job IMO  :wink:
Title: Re: Best place for small amount of Dynamat?
Post by: Chris 'N' Jen on 09 January 2008, 11:08
You may want to consider sending the power cap back as they are just a gimmic. They discharge in less than a second, after that they are just extra load on the system untill they recharge.

 :smiley: :smiley:
Title: Re: Best place for small amount of Dynamat?
Post by: BaxGTI on 09 January 2008, 20:34
Well, capacitor charge/discharge time (in seconds) is 5CR (5 x capacitance x resistance). So, as we can see from the box that the cap is 1.6 farads, the load would need to be 0.125 Ohms for it to discharge in 1 second... So I highly doubt this is so.

My sub has an impedance of 4Ohms according to the documentation, meaning for me with that capacitor the discharge time would be 32 secs (negating any other impedances)...

Or am I way off mark here?
Title: Re: Best place for small amount of Dynamat?
Post by: Chris 'N' Jen on 09 January 2008, 20:48
do a search on www.talkaudio.co.uk on power caps. they can explain things better than i can.
Title: Re: Best place for small amount of Dynamat?
Post by: Heyho on 09 January 2008, 21:16
Or more specifically: http://www.talkaudio.co.uk/vbb/showthread.php?t=20973

As for the sound deadening/flashing tape debate - you get what you pay for.  As sound deadening is pretty much just adding mass to panels in order to lower the resonant frequency of that panel, the best way to gauge the value for money is to compare weight for weight.

Look on ebay for sound deadening, and you'll come across edead - bitumen/butyl based deadening mat which looks to be jolly good value when compared with Dynamat or similar branded mat, but look closely and you'll see that although it's half the price of the "proper" deadening, it's also half the thickness, therefore half the weight.

There's nothing wrong with using flashing tape, but you'll find that you need to apply more layers to obtain the same effect as maybe one layer of a branded audio specific product. 

Dynamat also seems to trade on it's name, but there are other products out there that seem to get good press, and are better value.

http://www.caraudiodirect.co.uk/second-skin-damplifier-bulk-p-5503.html
Title: Re: Best place for small amount of Dynamat?
Post by: Ashmond on 10 January 2008, 12:31
Wouldnt waste it behind the number plate, get some good mastic for that.

Where do you put the mastic? Because in my mk4 what rattles is the wiring for the lights and the plate
Title: Re: Best place for small amount of Dynamat?
Post by: Len on 10 January 2008, 12:37
No idea what you're on about mate! I only said the plate which has nowt to do with wiring! And for that plonk a load of gunk between the plastic number plate and the cars metalwork! Then srcew it up!
Not rocket science!
Title: Re: Best place for small amount of Dynamat?
Post by: Len on 10 January 2008, 13:26
If you dont want to blow shed loads on dynaprat then you could try this :-

 http://www.wickes.co.uk/invt/243009

does the same job IMO  :wink:


The Lexus guys like it! :grin:
http://www.lexusownersclub.co.uk/forum/index.php?showtopic=22197
Title: Re: Best place for small amount of Dynamat?
Post by: Len on 10 January 2008, 13:28
Or try this heavy duty version!

http://www.directa.co.uk/site/scripts/product_browse.php?product_id=1807
Title: Re: Best place for small amount of Dynamat?
Post by: vr4000d on 13 January 2008, 10:51
the worst rattles in my mk3 were
bootlid
front doors
roof
wipers

the rear quarter`s were ok.

will be worth trying to tighten your boot catch a little to stop if rattling but it means you will have to slam it a bit harder;)

other than that just put it in a few places and see where the next rattle comes from.

flashing tape works but is nowhere near as good as proper soundproofing but then normal dynamat isnt great ideally you should use dynamat extreme or something like second skin products.
Title: Re: Best place for small amount of Dynamat?
Post by: Guy on 14 January 2008, 22:52
i think sound proofing is one of those jobs that however good a job you do there will always be one more thing that rattles... or has some resonance...  :angry:

using dynamat (or similar) will not only increase sound pressure levels... it will also reduce road noise meaning that you can hear more music