NEED HELP again!

[Ian D]

making a sub box. using two 12" subs, should have 1 cu/ft each, only got 0.8, i think this will be ok, but going to lose bass from it. should i port the box, or will that make things even worse? AND this is the one i really need the help on, does the sub box have to have a devider between them? the box is 1.6cu/ft does it have to have a devider to make each sub have its own 0.8 cu/ft?

[A. Waterfield]

it depends how much power you are running i proportion to the sub power.

how much is your amp pushing (power RMS)
and what are your subs rated at (power RMS) each

if you are over powering them then the 0.8 each is ok. If your underpowering them then it will sound s**** cos it has to move the vacum behind the sub. porting may be an option however it needs a lot of calculation



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[Marcos]

Depends on how you want it to sound as well. Porting it will make the subs sound more 'boomy' as the area behind the subs is no longer pressurised and hence, the cones can move easier. If you want your bass to sound tighter then you may not want to.

See what they sound like without porting, then, if you want more 'boom' you can allways drill a hole and slide a tube in.

One final tip, if you decide to port it, cut the hole and slide in quite a long length of tube. Start her up then gradually slide the tube out. This will alter the Boom/tightness ratio (does that make sense?!) This way you can 'tune' the port to how you want it to sound. Then once you're happy, just set it in place with some epoxy or whatever you're planning on using.

Hope that helps.

[Asht_200]

Part fill the box with wadding, it increases the effective volume.

[Daniel san]

0.8 will give you a hard bass, and be more punchy than 1.0cuft. 1.0 will be more musical.

If you port the box, it won't "drop" as low. The frequency response will drop off extremely quickly below the ports "tuned" frequency. It will also have a big spike in the response at the point the port is tuned to and will be louder there by around 3-6db. Wadding is a good idea, so is a nice big slab of Dynamat behind the woofer, on the rear wall of the box.

Also, did you make it out of boggo MDF, or proper Birch Plywood?

[Daniel san]

Oh, if you can, use a divider, it works much better when they aren't sharing air.

[Ian D]

I use 18mm MDF ply is to expensive, well good stuff. I know it is better, but I've always been told it doesn't help much!
I use fibre glass for wadding, and silicon all the joints then fibre glass it all for strength.

[fastfu]

1 CU/FT IS FOR 10" SUBS.

[Stevecarter200]

Originally posted by fastfu:
1 CU/FT IS FOR 10" SUBS.

That depends entirely on the sub.

And whether the box is ported or not.

The rule of thumb used to be 1 cuft for a 10", 1.5 cuft for a 12" and 2 cuft for a 15". This doesnt apply anymore as modern subs are now designed to work in smaller enclosures.