final sub questions

[darkthanatos]

Thanks to your advice ready to order parts for a budget sonotube sub just 3 more questions
List:
DAYTON SD315-88 12" SHIELDED DVC
DAYTON SA100 100W SUBWOOFER AMPLIFIER
Sonotube 18 X 24
4" PVC port, 9" long
F3=30
It looks like a 12" driver and a 4" port inside an 18" id tube is going to be very tight...

1. can I use 2- 2"x 4.5" ports instead? like this PORT TUBE 2" ADJUSTABLE Part Number 260-387

2. I will not do downfiring (thx for info on sag) so how important is port location? is port top mounting a must? or just equidistance?

3. the diameter/length of the enclosure can be changed if too tight, any last recommend? I simply picked 24" for space considerations, this can be changed

[tomdaugherty]

If you did your modeling with WinSID go back and change the ports to two 2" ports and see what happens to the length of the ports. Halving and doubling the ports will change the tuning. Tom Daugherty

[Chris Roemer]

> Thanks to your advice ready to order parts
> for a budget sonotube sub just 3 more
> questions
> List:
> DAYTON SD315-88 12" SHIELDED DVC
> DAYTON SA100 100W SUBWOOFER AMPLIFIER
> Sonotube 18 X 24
> 4" PVC port, 9" long
> F3=30
> It looks like a 12" driver and a
> 4" port inside an 18" id tube is
> going to be very tight...

> 1. can I use 2- 2"x 4.5" ports
> instead? like this PORT TUBE 2"
> ADJUSTABLE Part Number 260-387

> 2. I will not do downfiring (thx for info on
> sag) so how important is port location? is
> port top mounting a must? or just
> equidistance?

> 3. the diameter/length of the enclosure can
> be changed if too tight, any last recommend?
> I simply picked 24" for space
> considerations, this can be changed

You can go with TWO 3"d ports, about 10" long, OR
FOUR 2"d ports, about 9" long, OR
use a 20" id tube that's 20" long, and go back to the 4"x9" port.