Subwoofer enclosure building for 12" driver

[95SS]

Originally posted by: Viperoni
Very very long port, and it's quite narrow. I woudln't be surprised if there was some port noise.

For the 1.5cf tuned to 26hz, under 250 watts would be ok with a 3inch port, otherwise above 300 I'd recommend a 4incher.
You probably wouldn't hurt frequency response by bumping the tuning frequency up to 30hz, and that'd reduce subwoofer excursion (IE: smaller chance of bottoming out) in the region where most bass happens as well.

You won't really need a 1inch baffle, but if you want to, you can always do small braces on either side of the sub... maybe ones that are 2-4 inches deep coming out from the front baffle.

95SS, are you *SURE* he'd be running out of excursion in that box @ only 200watts?
Remember that WinISD gives you a peak to peak excursion spec, while ED lists their Xmax spec (correctly) as a one-way spec... total Xmax would be double their listed one.

Crap, that's right, I was wondering why it seemed so low. Been a while since I designed an enclosure.
<<<- Stupid 😀

 

[Howard]

Whew. Will I need a highpass filter then? 🙂

Viperoni, would it be better to go with a 1.5cf or 2cf enclosure? I'd prefer a flatter response.

 

[Howard]

If I go with the 2cf enclosure, it'll be 9.75"x15.5"x22.75"... That'll mean the driver goes on the largest face, with the 4"x16" round port parallel to the longest side. I'll most likely glue 2 3/4" panels together for the driver baffle, and use single 3/4" MDF for the rest of the walls.

It's ok if the driver is mounted off center, right?

 

[Viperoni]

np SS 🙂

Howard, you always need a lowpass filter on a sub 😉

Assuming WinISD's parameters for your sub are correct, I'd recommend the 2cf box tuned to 30hz with a 4inch port 16 inches long. It'll give you flatter overall response, and a bit more depth than the 1.5cf @ 26hz box. If you want a box, I've got my old one I need to get rid of: http://www.sounddomain.com/memberpage/313073/8
It's 2cf @ 30hz, all 3/4inch MDF. PM me 🙂

 

[Howard]

It's ok if the driver is mounted off center, right?

lol... I was thinking high pass. Do I need a high pass (say under 20Hz or something) filter?

 

[Viperoni]

Overexcursion will only become a problem below 25hz with 300watts, fortunately a tiny fraction of pop music goes that low.
Most jazz and classical doesn't even go that low at loud levels.

What I'm trying to say is: don't worry about it 🙂

 

[Howard]

Alright, I think I'm good to go. If all goes well, nourdmrolNMT1 will also sell me his Avionixx 400.2 amp. 🙂

 

[Viperoni]

Originally posted by: Howard
If I go with the 2cf enclosure, it'll be 9.75"x15.5"x22.75"... That'll mean the driver goes on the largest face, with the 4"x16" round port parallel to the longest side. I'll most likely glue 2 3/4" panels together for the driver baffle, and use single 3/4" MDF for the rest of the walls.

It's ok if the driver is mounted off center, right?

You also have to take into the account the port into your volume, as well as the volume of the MDF walls.
Also, will you be able to fit a 15.5" tall box in your trunk properly?

 

[Howard]

Originally posted by: Viperoni

Originally posted by: Howard
If I go with the 2cf enclosure, it'll be 9.75"x15.5"x22.75"... That'll mean the driver goes on the largest face, with the 4"x16" round port parallel to the longest side. I'll most likely glue 2 3/4" panels together for the driver baffle, and use single 3/4" MDF for the rest of the walls.

It's ok if the driver is mounted off center, right?

You also have to take into the account the port into your volume, as well as the volume of the MDF walls.
Also, will you be able to fit a 15.5" tall box in your trunk properly?

Ah, yes, I'd forgotten about the port volume. Guess I'd better do some more calculating.

Yes, I've got enough room in there.

 

[Howard]

New internal dimensions are 10"x15.75"x23". Port dimensions stay the same, I think.

 

[Viperoni]

Looks good, but dont forget the driver will also displace 0.05-0.1cf.
Hey, it all matters in the end! 😛

 

[Howard]

Originally posted by: Viperoni
Looks good, but dont forget the driver will also displace 0.05-0.1cf.
Hey, it all matters in the end! 😛

Grrr!

I'll just intentionally "miss" when cutting. 😀

 

[Viperoni]

LOL 😛