changing the tuning of a ported box?

polo2k · Post by **polo2k** » Sun May 11, 2003 11:39 pm

at the moment i am running 2 10" sony x-plod subs in a ported bod (center baffle so it acts like 2 boxes) and im noticing more and more that the box is tuned to about 260Hz so i was wandering if i bridged the amp and then ran the subs as a 2 ohm load could i pad one half of the box to give it a greater range of tune? if so what should i use (im thinking mdf well sealed to the base and then screwed

KarlM · Post by **KarlM** » Mon May 12, 2003 8:56 pm

You won't really notice a difference in KHz, but you will get a 'punchy' sound, the bass wont be as deep.

To tune the sound of ported boxes you need to alter the actual port its self. The diameter of the hole and the lenth are both contributing factors. You really need a expert to give you a bit better advice as i dont know which way you need to alter the port size.

PS if you need one if got a SPL test cd, with lots of assorted bass noises, from 60KHz down to the infamous 33KHz! (the rumours are true about 33khz as well, i experimented on the missus!!!!

)

KarlM · Post by **KarlM** » Mon May 12, 2003 10:05 pm

Just re-read your post, if your wanting something that can play a variety of Hz this is really down to your subwoofer choice, because no matter what box or amp you have, the sub will only work between the parameters its been designed to. this is called the frequency response.

You want to be looking for a sub that is 'high excursion' preferably a dual voice coil one. a good guide to freq response is the size of the surround, big fat surrounds tend to have bigger excursion, and so can play wider variety of notes. where as subs with a lot of cone area shift more air, so tend to be louder (but only play the high bass notes), look at any SPL car and you can see they all use phat surrounds, this helps with the competitions cause it means the subs can play whatever test cd the judges have.

PS the advice i gave above is correct if your just wanting to change the pitch of your bass, but it will only play the same freqs. it wont drop any lower

PPS - please post if you want me to find the best subs, i've got a good idea but need to check exact figs.

KarlM · Post by **KarlM** » Mon May 12, 2003 10:19 pm

*just sunk in that this is the first post where 2K has actually ASKED a question rather than answer it (i think)*

polo2k · Post by **polo2k** » Mon May 12, 2003 11:45 pm

no i have asked a couple before lol
and im looking at my options for this year when i redo my boot but id like to stay with sony as i like the sound and i might enquire about sponcership soon too
ps your next post is 200
and i have a test cd ask any one that was on the stand

KarlM · Post by **KarlM** » Tue May 13, 2003 11:48 pm

cool, sony have just launch a new range of subs over here, so they may be looking for a demonstrator over there, they've just released a range of hexangonal subs, which are designed to shift more air (like the Kicker L7 squares).

you would supprised what you can get in return for sponsership, so far i've managed to blag the following :

-New bodykit inc both bumpers, side skirts and rear spoiler (not including paint though)
-Set of TSW pace 19'' alloys with tyres
-half price leather re-trim

So the moral of the story is - if you don't ask, you don't get!

polo2k · Post by **polo2k** » Wed May 14, 2003 12:13 am

and where would i send an e-mail to ask

KarlM · Post by **KarlM** » Wed May 14, 2003 12:24 am

I'll try and find out who is the importer for France, but it will have to wait til the morning!!! i don't think he'd understand if i rung him now!!!