I've been wanting to build another sub, and purchased this driver a while back, intending to build an infinite baffle design published in audioXpress. Then a construction project at my work had some leftover sonotube, and I'm contemplating something different. The only thing is, it's 36" diameter tube! There are two, each about 30" tall, for about 18 cu. ft., each! I did a little playing around with WinISD, and it seems that an enclosure that big just makes the slope off to the left more gradual.
Is there any point to trying something this big? What about a different driver, maybe something in the 15-18" range that isn't too terribly expensive, that I could play around with?
They were free, so I just wanted to experiment!
Is there any point to trying something this big? What about a different driver, maybe something in the 15-18" range that isn't too terribly expensive, that I could play around with?
They were free, so I just wanted to experiment!
Apart from the other good reasons subs might be too big, you may care to avoid half-wave resonances in the pipe. 30 inches top to bottom yields about a 60 inch wavelength, or about 220 Hz. 36 inch diameter implies a 72 inch wavelength, or about 185 Hz. You really want the crossover to leave minimal energy at those frequencies to avoid strange peaks in the low midrange.
The 18" woofer mentioned before would likely go lower than the 12" for the same power input. There's 12dB difference in efficiency. Compare them with the SPL chart on winISD, set the power input to the same. Methinks the 18" would be far better. There's also excursion-related distortion to worry about with relatively small drivers.
If your interest is music, there's barely any recording with stuff under 30 Hz. Of course, that may be of great interest to you or you thrive on repetition, can't say.
I like sealed boxes. They do a few things I like: provide enough cubes so as not to raise the driver resonance over your chosen set point (please ask the modelers with Windows machines, but I'd guess 5 cu feet is plenty for your driver), give a free boost at that resonant point (no sense making it too low, eh), and protect the driver from unrestrained excursions below that resonant point (go remind the bass-reflex or TH crowd of that virtue).
As far as I know (and I surely wish somebody would correct me, please) there's only one parameter worth thinking about for really low sealed boxes and that is simply the resonant point with Q being aurally insignificant.
Oh yeah, the other parameter might be "spouse approval quotient." But sealed boxes are good that way because there're no terrible constraints on shape. You could use a sewer pipe (as Briggs did).
Good luck.
I like sealed boxes. They do a few things I like: provide enough cubes so as not to raise the driver resonance over your chosen set point (please ask the modelers with Windows machines, but I'd guess 5 cu feet is plenty for your driver), give a free boost at that resonant point (no sense making it too low, eh), and protect the driver from unrestrained excursions below that resonant point (go remind the bass-reflex or TH crowd of that virtue).
As far as I know (and I surely wish somebody would correct me, please) there's only one parameter worth thinking about for really low sealed boxes and that is simply the resonant point with Q being aurally insignificant.
Oh yeah, the other parameter might be "spouse approval quotient." But sealed boxes are good that way because there're no terrible constraints on shape. You could use a sewer pipe (as Briggs did).
Good luck.
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Hi there Ed: Use search on this forum for: sono subs. Many sonosubs threads exist there. As I recall Steve Cassals (spelling?) from St. Louis, built a sonosub from 28-inch tube usng a 21-inch driver. The ported design had two tubes nested, upward firing driver and ports. Also, sono tubes can be modified to conical shape by cutting-out a triangular section and gluing the main tube back together with liquid nails type construction glue to make a folded design. Also there is El-Pipeo, by Nelson Pass and some clones of these on the sono sub threads. Hope you will post your design, construction details and listening evaluations. ...regards, Michael
Hi,
Has anyone suggested the Pyle Pro PDW21250 yet? They finally got a manual for it:
http://www.pyleaudio.com/manuals/PDW21250.pdf
Regards,
Has anyone suggested the Pyle Pro PDW21250 yet? They finally got a manual for it:
http://www.pyleaudio.com/manuals/PDW21250.pdf
Regards,
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