Port Length, Help!

[Eskii]

You would have really high port velocity if you port that box either way. The smaller the port the lower the tune. The longer the port the lower the tune. I assume that the 1.85 cubes includes the port? So any port takes up air space along with the sub too. So to get that low tune you need either small port that is short (really high port velocity) or a large port (10-16 square inches per cubic foot of box) with a long length to get the lower tune. That is fine but you only have that 1.85 cubes to work with and the port would start to gobble up your space. So... you get back to the high port velocity again.

I have been putting numbers in Bass Box Pro and I just can't make it work with that tune. 3 10s with their displacment, plus a port that is only 12sq inches that is 18 inches long gives a remaining internal space of around 1.4 cubes (less than the recommended) and tunes to about 32-33 hz. That gives a really high vent velocity and poor low end output.

I just don't see it happening. But you could proove me wrong- that space is just killing you.

note that the 1.85 cu.ft is including the drivers displacement

[lance_aka_64]

You would have really high port velocity if you port that box either way. The smaller the port the lower the tune. The longer the port the lower the tune. I assume that the 1.85 cubes includes the port? So any port takes up air space along with the sub too. So to get that low tune you need either small port that is short (really high port velocity) or a large port (10-16 square inches per cubic foot of box) with a long length to get the lower tune. That is fine but you only have that 1.85 cubes to work with and the port would start to gobble up your space. So... you get back to the high port velocity again.

I have been putting numbers in Bass Box Pro and I just can't make it work with that tune. 3 10s with their displacment, plus a port that is only 12sq inches that is 18 inches long gives a remaining internal space of around 1.4 cubes (less than the recommended) and tunes to about 32-33 hz. That gives a really high vent velocity and poor low end output.

I just don't see it happening. But you could proove me wrong- that space is just killing you.

WOOT!!! about time you started to post here.

[Colin - STAPUFT]

WOOT!!! about time you started to post here.

what's up son!!!!!

[Boon]

That's not enough port area for that much cone. You tune the port to the box but you have to allow for cone area when figuring out port area Just means you need longer ports.

What's the dimensions? Could you fit 4 4" aeroports either firing up or firing across the box? The flares will reduce port noise, otherwise you're gonna need a shitload of port to stop it chuffing. Ideally you would need about 15 sq.in for EACH sub, as mentioned... I figure this box is going across behind the seats, could you have external slot ports that extend out under each seat or something?

[Eskii]

That's not enough port area for that much cone. You tune the port to the box but you have to allow for cone area when figuring out port area Just means you need longer ports.

What's the dimensions? Could you fit 4 4" aeroports either firing up or firing across the box? The flares will reduce port noise, otherwise you're gonna need a shitload of port to stop it chuffing. Ideally you would need about 15 sq.in for EACH sub, as mentioned... I figure this box is going across behind the seats, could you have external slot ports that extend out under each seat or something?

Could be an option, hmmm. I'll get back to the drawing board!!!

yeh thanks, i thought i needed more port area

[Eskii]

That's not enough port area for that much cone. You tune the port to the box but you have to allow for cone area when figuring out port area Just means you need longer ports.

What's the dimensions? Could you fit 4 4" aeroports either firing up or firing across the box? The flares will reduce port noise, otherwise you're gonna need a shitload of port to stop it chuffing. Ideally you would need about 15 sq.in for EACH sub, as mentioned... I figure this box is going across behind the seats, could you have external slot ports that extend out under each seat or something?

Could be an option, hmmm. I'll get back to the drawing board!!!

yeh thanks, i thought i needed more port area