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Posted: Tue Jun 12, 2007 2:44 pm
by Member02
Explain Better Please

Posted: Tue Jun 12, 2007 4:01 pm
by fbi90909
just make really really really big pipe bombs. :D

Posted: Tue Jun 12, 2007 4:13 pm
by Member02
haha...

on a side note, it is 1.78cu ft sealed right now (horribly sealed, just flat on floor and sub up top forced into place)

and it's rediculously loud with my 100 watt Audio Art amp powered by my 25 amp power supply...

Seems to peak around 50hz to my ears... moves an easy half inch, I figure I'll get the bigger tube over here see if sealed and taller makes it lower.

Posted: Tue Jun 12, 2007 6:24 pm
by todd.brust
CBFryman wrote:Quarter wave FTMFW. Get two 90* elbows. 14' total for 20Hz.


how'd you figure that? i have never really understood the whole quarter wave thing

Posted: Tue Jun 12, 2007 6:28 pm
by CBFryman
Speed of sound is 340m/s

340m/s / 20 cycles/s = 17meters/cycle (seconds cancel)

17m*100m/cm = 1700cm

1700cm/ 2.54 * 12 = aprox 14 feet.

Posted: Tue Jun 12, 2007 7:51 pm
by todd.brust
where did you figure that 14 ft is only quarter wavelength? or is that the full wavelength?

Posted: Tue Jun 12, 2007 8:07 pm
by CBFryman
todd.brust wrote:where did you figure that 14 ft is only quarter wavelength? or is that the full wavelength?

The above is for the full wave length. I messed up. Decide that by 4 and you get 14. This puts the front and back waves in phase close to 20Hz.:)

Posted: Tue Jun 12, 2007 8:11 pm
by Member02
ok, the only problem I see is finding the fittings for this pipe... I searched all over google, no fittings for 12.5" pvc pipes...

help me look around yall


by the way, by your math, the quarter wave is ~7ft

Posted: Tue Jun 12, 2007 8:29 pm
by Member02
17m is 20hz, to feet *3.28= 55.7ft

divide by 4=13.94ft

you got the number right, but the math you typed didn't match the number, hehe... but I would've checked anyhow.

Posted: Wed Jun 13, 2007 12:20 am
by todd.brust
sweeet

i want one