Apartment dweller thinking of Sonotube usage (new member)

[windcrest77]

Hello,

I just joined but have been reading speaker builder magazine since inception and making speakers since 1973 when I could not afford speakers in high school, just for hobby (on and off).

Well now I live in an apartment and really have no access to a table saw, and a set up to make cabinets, etc. But I could do simple gluing taping and small wood part fabrication and fastening. I was thinking if it might be possible to make subs with Sonotube (the concrete form tube) and adopt Bill's designs to that. Something like this:

http://www.svsound.com/view-all?page=sh ... duct_id=17

Has anyone done a sub with sonotube for DJ purposes? I would think if you could pull it off the weight factor would be very favorable since Sonotube is just thick coated cardboard. And by placing the speaker at the bottom it would have a nice low center of gravity from falling over etc. Ports and possible horn would be at the top. Maybe even 2 or 3 Sonotubes can be strapped together and connected with a box to make a longer throat, etc. Given a good design even an apartment dweller should be able to cobble up a prototype with duct tape and Sonotubes from Home Depot, no? Could the Tuba's sonic design somehow be replicated with Sonotube? Ultimately I would like to use a Neodymium magnet speaker with a composite basket and class D amp and Sonotube for an ultra-lightweight sub package. Thoughts appreciated.

Thanks
Rick

[windcrest77]

Additionally I would see a design where 2 slightly offsized Sonotubes telescope into each other (like a whip antenna does) to tune the box or simply provide a way to make the whole unit smaller for transport purposes. When you get to the gig you slide the tube up and double the internal volume of the enclosure, when you load it in the car you collapse it.

[Gregory East]

Nice idea. Not going to work.

Horn pressures are very high. Folded horns is folded and tubes don't fold. Duct tape isn't PL. Forget it.

[BassMe]

Only thing I can think of is using straight horns. But I don't think their will be much technical support available here. Not what we do.

We have had members construct subs using a circular saw and their dining table. It's doable as long as you think it out. Hell I built a projector with a jigsaw and some milk crates in my lounge/patio.

[Gregory East]

I recall a circular saw being employed in a bathroom.

[windcrest77]

Nice idea. Not going to work.

Horn pressures are very high. Folded horns is folded and tubes don't fold. Duct tape isn't PL. Forget it.

Thanks, I was thinking the folded horn would be created with concentric cylinders nested. For example the outer cylinder would have a diameter of say 24 inches, then another inside that at 16 inch diameter, then another inside that at 8 inch diameter, etc. If the whole unit were 4 feet high that would be a horn almost 12 feet long that flares from 8 to 24 inches. The only place for leakage would be capping the ends on the tubes with wood circles. Those would have a groove for the tube ends and would impregnate the tube end in a deep groove filled with PL, no chance for a leak. The idea would not be to fold the horn, but instead get each concentric cylinder to fire into the next by nesting them and making each inner cylinder slightly shorter, with its outer cylinder capped at one end, then firing into the next cylinder at the other end, etc like a bucket brigade. The speaker would sit at an end of the inner most tube (bottom), the outermost tube would be the final horn exit, the middle cylinder(s) just ping-pong firing into each other to make the horn very long. With 4 tubes you could make a 16 foot horn fit in 4 feet of height and be light as cardboard. Cylinder shapes are also naturally very strong to pressures and immune to standing waves, (thats why pressurized gas is never held in anything square).

I'm just brainstorming, I appreciate the scrutiny.

I suppose I should draw a cross-section picture of the "folded cylinder horn" and post it, its hard to explain how to make the nested cylinders fire into each other.

[BrentEvans]

If the whole unit were 4 feet high that would be a horn almost 12 feet long that flares from 8 to 24 inches.

Problem is, it really wouldn't be a horn, it would be a series of cylinders. One of the most important qualities of a horn is the flare rate. The design you propose would have a highly inconsistent flare rate, if you could even call it that.

[subharmonic]

The only way I see this design folding would be like a W bin configuration, but there are so many issues to overcome. Not to mention the basics of a horn design from scratch, that in itself is a major hurdle. You have bracing, driver mounting, access hole(s), air tightness, driver selection, and architecture/construction technique. Even with a shop full of tools this seemes like a beast of a project. Not trying to be a negative nelly, just saying what comes to my mind.

[Bill Fitzmaurice]

When I lived in New York City I built a pair of Klipsch style corner horns in my apartment, using only handheld power tools. There isn't a cab in our lineup that can't be built the same way.

[Tom Smit]

Hi, and welcome to the site!

Part of the horn design as was recently told, is the flare rate. Look at this pic to get an idea of what I mean.