Question for Aussies - LSK S150 sub or build other?

[rabbitz]

Try designing a vented XLS box and you will find the vent is too long for the box.

I only did a 10" XLS but overcame a long vent by snagging a B&W Flowport from a dead sub. Ended up with a port only 65mm dia x 254 long which fires down. Should chuff like crazy but super quiet. Great design.

 

[paulspencer]

Very interesting technology behind the B&W flowports - I read comments in one of their papers. The concept is similar to a golfball. Was it a downfiring vent? I find it can be more difficult if downfiring as the transition from perpundicular to moving along the surface of the floor can be sudden.

 

[rabbitz]

Yeah, the original B&W sub it came out of was downfiring so I just maintained the same height by using the cones that supported the sub. Have not had any problems with the downfiring port......... very smoooooooooth (if you can call a sub smooth).

 

[paulspencer]

When the vent is downfiring, if the clearance has a certain relationship with the vent diameter then it can lower tuning by 2 - 4 Hz which can help you get a shorter vent, but if it's too close then you can lose output as well and have turbulence problems. It can be a fine balance. In your case the diameter is small and the downfiring won't probably affect the tuning much if at all.

 

[rabbitz]

Stuck with the B&W dimensions as they've done all the hard work. I've done some other subs with downfiring ports and found that a height of about 70% of the port diameter sounds the best in my room. Probably a formula out there somewhere but just did some simple tests.