Dating back to the '90s, I've always stuck with good old fashioned fiberglass insulation batts as I recall it has shown measurable, though not huge, advantages over other commonly used stuffing materials. And Ken Kantor, founder of NHT, did some extensive research, including testing various materials, that he shared with the DIY community back in the day. I believe Dickason's LDC also covers this phenomena pretty well. Fortunately, the internet never forgets: GlassWolf's Pages Tom Nousaine, RIP, published a decent experiment on this back in the '90s. That should be a 35.Everything old is new again. It looks like the B&C has a Resonant Frequency of 32 Hz. At 20 Hz, the wavelength is about 55 feet, and this is where a 14 foot tube will resonate. For sound going through air, that speed is approximately 1100 feet per second. The wavelength of a frequency is the speed the wave travels divided by the frequency. This effect is exploited in numerous musical instruments, particularly the pipe organ. In any tube shaped object, closed at one end, a resonance develops at the frequency where the wavelength is four times the length of the tube. So it seems like I'll be able to cut these things down after all, and not worry so much about the ceiling height.Ī transmission line is a different approach to achieving a similar effect. It looks like I should be able to make this work with a tube 9' long actually, stuffed with fiber fill or whatever. I'll also look into your amp suggestion, for sure! Do those have a built in corssover, or should I build one?
#UNIBOX SUBWOOFER DRIVER#
I'll likely look for a better driver at this point, with more displacement. Why the question about spacing with the ceiling? Are you planning to put the driver at the top or locate a port at the top? Or are you planning to leave the end open? If you leave it open, the sub now becomes a transmission line and you have to be very careful with dimensions due to resonances created by the tube. It's important to have lots of power reserve for peaks in your music/movies. More often than not, it's distortion that blows up speakers rather than too much power. Don't worry that the power output is higher than the driver. You can get a 3000W class-D amp for about $280.
#UNIBOX SUBWOOFER PRO#
If you're on a budget, lots of folks like to use Behrenger pro amps, such as the iNUKE series. I haven't simulated both to see which will play louder at low frequencies, but the Ultimax likely will. For example, the PDW21250 has a volume displacement of 1535 cm 3 (area*xmax) while the Dayton Ultimax 18 has a Vd=2681 cm 3. High SPL requires moving lots of air and a larger driver doesn't necessarily mean more air movement.
#UNIBOX SUBWOOFER DRIVERS#
Plug the numbers into a simulation program (I like Unibox but there are lots of choices out there) to see how various drivers perform. When choosing your sub driver, you should consider how low you want it to go (obviously as low as possible, but you should have a number in mind), how loudly you want it to play, and how much amplifier (power) you're willing to buy. If you've gotten this far, I appreciate you looking! Any advice you can give me would be awesome! Thanks! At that point I don't think she will be able to stop this project from happening. I'm hoping to get the sonotube upstairs before my wife gets home from a vacation. How much room do I need between the sonotube and the ceiling?Īny ideas on what kind of an amp I'll need to power the 21" driver? You can see the shape of the cut needed in this diagram at the end of the album. Definitely I'd love some suggestions for something better though.Īny ideas if cutting off the top corner of my sono tube is going to be bad? I think I'm going to need to do this to have some room between the tube and the ceiling. I know Pyle is pretty shitty, but the price is right, and it has okay reviews. I need to cut off a "corner" to fit the thing into my living room, once it has a speaker under it.Īny driver recommendations? I'm considering starting with a Pyle PDW21250. My sonotube is already sitting in my basement, propped up on stands to keep it round.
Use a 21" Driver and a 24" Diameter x 12' tall sonotube. Hi! I made a similar advice seeking post to r/hometheater, but this will focus strictly on the subwoofer.īuild a really big subwoofer.
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