Please help me finalize my tempest sonosub (1 Viewer)

[DaveNaumann]

I have started to construct my tempest sonosub. However, I have a few questions about the design I must answer before I can finish it. I am using a 20" sonotube and will be powering it with a pe 250 watt plate amp. After reading through adire's recommended box designs I feel that the vented adire alignment suits my listening tastes the best. I basically would like to mimic that enclosure using a sonotube. I figured on keeping the 214L volume and 15.4 Hz tuning point. I was wanting to use a single 6" port instead of the 2 3" flared ports. However, when I use lspcad it shows that if I use a single 6" port it must be ~35" long. Is 35" too long for a 6" dia. port? Or should I just raise the tuning point to shorten the port? Also, when stuffing the sub, is it better to use batting around the tube or to just throw loose polyfill in the enclosure? If anyone has any other tempest enclosure recipes feel free to share. Thanks in advance for the help!

Dave

 

[Chris Tsutsui]

64oz of polyfill is a LOT so you'll be fluffing it and filling up the enclosure.

35" is pretty long for a port, will it fit without a bend?. I went with the two flared 3" diameter ports mostly because it was one of the diameters in which I could easily find the flared ends.

 

[Chris Carswell]

How tall is your tube, ~42" if my math is correct.
35" is about right (WinISD gave me 36") for the port so you can use it in your tube. Keep it away from directly behind center of the sub (the vent in the magnet, pole piece).
Using 6" tube, a 30" port is tuned to 17Hz, 20" port is tuned to 20Hz. I wouldn't go any higher than 20Hz.

If you need to check any 3" or 4" port calculations LMK.