20 replies to this topic

[Carlzilla]

right, i have a jbl gt5-12 subwoofer which performs better in a sealed enclosure. reccomended volume is 1cubic foot. the last enclosure i had was 1.25 cubic feet and sounded perfect.

With the boot lining kit i have, which was pre-made by optimise, i only now have 0.6 cubic ft of volume, and so, the sub doesnt sound as it should.

is there any fix for this without increasing the boxes size, or porting a small box, as i feel that may make the problem worse rather than better.

any help appreciated from the gurus

[Sam Walters]

I think due to the volume of the box being changed, its changed where its peaking therefore giving a slightly different sound....

But a solution to your problem!

http://en.wikipedia....i/Standing_wave

i don`t really fancy going into the science of it, because well im sleepy but still have work to do at the moment. (Taking a naughty brake!)

Fill the box with polyester pillow inners. rip it to shreds and wack it in there. Should help you out a little.

[Burnard]

Well given your criteria, If you cant extend the box, or port it, i think the only fix is to change the sub?

[Sam Walters]

Not exactly, my method will change the tuning of the sub in combination with its box., its not perfect, but its worth a shot surely?

[joakwin]

get the same sub in a 10 inch version and it should be good in that .6 cu ft^3 sealed

[pbrain]

as mentioned, try speaker wadding (my mate swears by it for PA cabs and he makes some incredible & very small sub-bass cabinets) also, another way you could increase your box volume is mount the sub facing into the box (with the magnet on show)

[roberts]

Hello,

Yeah it's a difficult one, as the boxes are designed for 10" subs with a capacity of 20 litres. Try the above but if not I'd recommend fitting a 10".


Thanks
Andy @ Optimise Automotive

[Crowson_punk]

definately wadding!!!!! does do wonders when it comes to box tuning

Jon.

[Carlzilla]

only one problem to changing to a 10" sub, i have a 12" hole to fill!!! (already had the 12" beforehand, and to me a 10" unless expensive, just doesnt cut the mustard)

So that is COMPLETELY out of the question

ill give that speaker wadding a go, thanks for the replies.

i did think about the magnet out approach, but because id previously had it setup like the photo below (until some thieving gits decided to rob my car, got everything back though) id have 0% room left to put anything, and the rear of a gt5-12 isnt really eye candy o.O

Also andy, i dont know if youd be able to do this easily, but id reccomend that in the box instructions that after installation, the joins on the inside of the enclosure be sealed with some kind of silicone sealant, it stops the farting noise the enclosure creates when air escapes when it shouldnt be doing so
If the enclosure fits into the boot prebuilt (like mine did) its definately worth doing before the rest goes in.

Edited by Carlzilla, 21 June 2010 - 03:47 PM.

[Carlzilla]

Found a solution to my problem

pictures up later when its fully finished

[Carlzilla]

Todays project has been finished

i padded out the box with foam i had lying around in the garage, and although it made a noticeable improvement, the sub was still lacking 'volume' when hooked up to my test rig in my bedroom

so i then went with the idea of using the redundant space above the wheel arch, that the sub original kit doesnt use. It just so happens that the enclosure was 0.6 cu ft, and the 'add-on' box carried 0.4 cu ft volume, the magic 1 cu ft enclosure volume for the sub, Bingo!
when the sealant dries ill let you all know how it sounds

Edited by Carlzilla, 21 June 2010 - 09:03 PM.

[roberts]

Also andy, i dont know if youd be able to do this easily, but id reccomend that in the box instructions that after installation, the joins on the inside of the enclosure be sealed with some kind of silicone sealant, it stops the farting noise the enclosure creates when air escapes when it shouldnt be doing so

It's something that has crossed our minds - but not something we will be offering with the product. We have thought about offering sealed enclosures at an addition cost (P&P will be the expensive cost).

Also, we are currently working on an 'Essential Guides' section for the website that will include detailed fitting instructions for all our products - this will include suggestions and ideas to get the best out of each product e.g. sealing sub boxes etc.

Todays project has been finished

i padded out the box with foam i had lying around in the garage, and although it made a noticeable improvement, the sub was still lacking 'volume' when hooked up to my test rig in my bedroom

so i then went with the idea of using the redundant space above the wheel arch, that the sub original kit doesnt use. It just so happens that the enclosure was 0.6 cu ft, and the 'add-on' box carried 0.4 cu ft volume, the magic 1 cu ft enclosure volume for the sub, Bingo!
when the sealant dries ill let you all know how it sounds

Looks like a good project - if you don't mind I'll pinch a few pictures for the gallery.


Thanks
Andy @ Optimise Automotive

[Carlzilla]

no problem andy, go for it, glad to be of some help and provide feedback

[POWER5LAVE]

nice job carl and id like to say my insides have never felt so shook up since i fitted the twins on the back seat lol. what watt amp was you using to power them if you dont mind me asking

[Carlzilla]

Only a 250w 2 channel , and they were stupidly loud then. The subs for the sum of £40 ea are very good

using the same amp now, but bridged for the single