Looking To Build SPL Subwoofer

[Mista_Bishi]

Hey everyone,

i just picked my jaw up off the floor after hearing about a SINGLE 6 inch custom home made woofer pulled 151.2 Db on the new TermLab setup and all i can say is INSANE!!!!

So atm i know NOTHING i have been linked to this site looking for how to build a sub. I have 2x 8 inch woofers that i can spare to pull apart and experiment with the specs for the sub is......

SPECIFICATIONS
Nominal impedance: 4 ohms
Power rating: 100WRMS
Sensitivity at 1W @ 1m: 88.35spl
Voice coil resistance (Re): 3.5
Resonant frequency (Fs): 35.71
Mechanical Q factor (Qms): 2.408
Electrical Q factor (Qms): 0.457
Total Q factor (Qts): 0.384
Equivalent volume (Vas): 42.87
Voice Coil Diameter: 35mm
X max: 5mm
Magnet Diameter: 120mm
Magnet Height: 40mm

I thought hey for $49 (Aus Dollar) you can go wrong here is also a picture of it as well.



So if someone could tell me where to start that information would be greatly appreciated, sorry if im asking to much of you guys but i figure a couple of hundred brains are definatly better than mine.

Thank You Very Much
Marc

[fr0st]

That looks alot like a venom.....
There not regarded for thier high sound quality but its a start.
Google for WinISD, it lets you put in all the parameters of your sub(s) to deternines a suitable box. It lets you play with the sizing & tuning aswell so it suits your tastes.

I have 2x 8 inch woofers that i can spare to pull apart and experiment with...

If you actually want to rip apart and rebuild the sub (I think thats what you may have been getting at) then theres onlt two things you can really do. Replace the magnets with neodynium and rewind the voice coil with less turns (If you increase the magnetic field, the impedence goes up so you need to have less turns to get the same impedence)).
Dismantlng the speaker is harder. you'll need some craft knife skills to get the spider out without damaging it.

Good luck

EDIT: Your name seems familar... are you CAA?

[Mista_Bishi]

HAHA Yeah man im from CAA, been there a while now.

But nah i know how to build a loud box man thats the easy part these days, but im looking to do something different what i had planned was maybe put another double stack of magnets making a quad stack of magnets so i can make or buy a larger former, then replace the spider and the rubber surround so that i can get HUGE cone movement. Tuneman from CAA made this custom speaker and used a spider for a surround its nutz!!


And that 6 inch hit 151 DB!!!!!!

But anyway yes it is a venom and yes i wanna chop it up

Also as for sound quality they are alright i had a pair in the front doors of my mirage



As you can see that was like about an hour of the final coat of fiberglass dryin i didnt even sand it just installed for a cruise :P

Later
Marc

[Karel30]

I found a nice site:
www.ehqc.com
maybe they can help you.
good luck.

[offroadbum]

i`m not sure what your so happy about.
this install shop i know has a cheap 6" hooked to a cheap 50w amp.that they put into a road cone that hits 150.
my self i think that it`s ez to get from 145 to 155.after that is where the work comes in.

[Mista_Bishi]

Originally posted by offroadbum
i`m not sure what your so happy about.
this install shop i know has a cheap 6" hooked to a cheap 50w amp.that they put into a road cone that hits 150.
my self i think that it`s ez to get from 145 to 155.after that is where the work comes in.

Mate if its so easy why dont u show me some pictures of these 6 inch speakers that go so well along with a pic of the termLAB readout i find it very hard to swallow. Plus if u guys do it so well why dont u offer me some advice like i orginally asked for.

***LATEST NEWS!***

Ok im 99% sure im going to buy the magnet and coil from a DD (Digital Designs) 9515 and match them up to the basket and the woofer. Im also thinking of making my own cone but a flat one like the Earthquake "Magma" range of subs, seeing as tho it needsto be light yet strong i am thinking of making it like this. 2 Layers carbon fibre, 1 layer of .6mm Aluminium sheet, and final layer of carbon fibre. I thinkthat should be strong enough but ill soon find out i guess. Plus the coil configuration im going touse is the Dual 1 ohm coils. Looks like things are starting to move along

Later
Marc

[fr0st]

A DD9515 magnet won't be of huge use to you unless you mod the whole magnet assembly. If you look at your venom, it should have the bottom plate and the pole piece made out of one bit of steel. Around that are the magnets, and then a steel disc on top of that that creates the voicecoil gap. The thickness of that top plate and pole piece/bottom plate will limit the maximum magnetic field you can create in the gap.
I would definatly use neodynium as the magnet aswell. neodynium packs more magnetism into a smaller space so you don't have to extend the pole piece to occomadate the 9515 magnet (which would be farking huge).
In order to stop the top and bottom plate saturating you'll need to add an extra layer to it and maybe the polepiece aswell, but adding to the pole piece will mainly increase linearity.
I thought you can't use custom speakers and amp in comps?
That's what i was told about my amps a while ago

Let me know how you go, I'll have over 3kw on tap in a few weeks to do some experiementing

[Mista_Bishi]

Hey fr0st,

Mate see i think this will work and ill say it again incase i worded it wrong.

1) Carefully remove standard cone from jaycar sub

2) Remove the coil and former from the jaycar cone

3) Remove magnet from jaycar basket

4) Replace magnet with DD 9515 magnet

5) Replace coil and former with 9515 coil and former

6) re-assemble

Now the 9515 is dvc as well, but anyway after ive done all that i'll knock up a box and ill feed it 2500 rms and seehow she holds up after a big BUUURRRRRRRP

But im not using it for competition im just doing this for a giggle and to see what the difference is between a stock speaker and my hotted up one.

By the way where bouts u from fr0st??

Later
Marc

[fr0st]

Do you have the full 9515 motor? (magnet, pole piece, back plate and top plate?)
Also, have you checked the former size and each speaker. I'd imagine that the DD sub would have about a 3 inch VC, the venom at max would be a 2.5".
Another thing you havn't considered is that the impedence isn't solely dependent on the number of windings of the coil. Compared to the 9515, the venom will only be able to handle a certain amount of flux in the gap without reenforcement of the top and bottom plates, which will be less than the 9515. If you use the same coil and former, the impedence will be less than one ohm. Say if you increased the magnetic field by having say two 9515 magnets, the impedence would increase since theres more magnetic flux in the gap.

All that would disapear if you used the entire 9515 motor assembly. But why waste a 9515

I'm from perth btw
I work for a Jaycar reseller so i might get a 12" and try this
a bike innner tube cut in half may be a good surround

[Rosu99]

Hello! I´m new in this forum
I really got interested in this 6inch woofer
since I have competed in dbdrag..

I got alot of questions to your 151 db statement..

was it measured on the dash in a car or closer to the speakerbox?

what frequency were used when measuring 151db?
above or below 80Hz?

what kind of magnets are used ,and how is the polepiece made
when 3! double stacked magnets are used?

are there more than one voicecoil in parallell ?

thanks