It seems like the surface area reduces the auduble output.

I had been using a single 3" round vent for my 12 so far and when I lowered the tuning freq from 35 to 31 I lost 3db in sound, Im pretty sure the lengthening of the tube clipped the backwave and lowered my db output. I doubled the area by adding another pipe and recomputing the lengths/volume and it seems to have opened up the low end significantly.

From this:



To this:



I wasnt sure if the fact that the port was at a 0 degree phase and now is at a 90 degree phase would have anything to do with it either.

WinISD doesnt computer port efficiency beyond whether or not it will whistle. Anyone (toby) able to compute the loss of output due to insufficient port surface area?

 

i got 0ne of those subs in a box,with rectangle port,and it pounds,maybe you should try that

 

the shape of the port makes no difference, that I know. its surface area, air friction, and surface resistance that matters. I just want the formula to calculate energy loss at a certain pressure.

 

You still using that frankenstein box? I prefer slot ported as well.

 

yeah its on its last leg but im hoping to find the sweet spot formula before I build a new one.

 

You should slap a couple gauges on it, some christmas lights, and write "Time Machine" on the side.

 

SHHHH thats my secret plan!!!!!

 

then sell it on ebay

 

damnit u guys keep this on the hush! the feds are gonna be all over me

 

that made me laugh so hard a little pee came out!