What's your opinion on this ?

[fishchris1]

So I just built an enclosure for a Sundown Audio 8" sub. Like a lot of you (I'm assuming) I was totally anal about getting my cubes spot on ! I was shooting for .75 cu ft. Of course I subtracted for speaker and port displacement, but even a few cubes for silicone, and a little spacer block for the port... Etc.

But here's my question, even for guys that try to figures there cubes and port length to the 4th decimal point like I do, how often do you think our boxes come out to exactly what we are shooting for ? Both cubic footage wise, and tuning wise ? 

And do you / how would you check these things after the fact ? Easy enough to shrink your cubes afterwards, and sometimes to shorten port lengths....

[Triticum Agricolam]

Ending up with the net volume you desire isn't too tough, you just have to assume the manufacturer has given you accurate information in regard to the displacement of the sub.  The good news is that if your net volume is off a little bit its not going to make much difference.  

Getting the tuning you want is much more of a crap shoot.  Tuning frequency calculations are much more of an approximation.  Plus there are outside factors that will affect tuning (temperature, barometric pressure, etc).  You can test to see what your tuning frequency ACTUALLY is once you get the box playing by playing sine wave tones at moderate volume while watching/feeling for cone movement.  The frequency where cone movement is the least is your tuning frequency.