My Very First Tempest Sonosub (1 Viewer)

[Peter_A_M]

Hello all,
I'd like to build a Tempest-based sonosub, and even though I've been reading through this site and others religiously these past 3 weeks, I have a few lingering doubts about whether building such a subwoofer is possible, as this is my first foray into the wonderful world of DIYing. Still, here goes:
I mainly listen to jazz and classical music (about 98% of the time) and watch DVDs the rest of the time (about 2% of the time). Based on these percentages, I believe the low Q sealed Tempest design as set out in Adire's Sealed Tempest Applications paper would best serve my needs. I also figured out I'd need a 24" diameter, 31" long sonotube to achieve the recommended 230 L net volume, but based on the 35" x 24" x 24" box dimensions (330 L, 11.67 cu. ft.) Adire recommends, I'd need a 45" length sonotube, stuffed with 64 ounces. of polyfill, I suppose.
A few questions:
1) Would 45" be the best length for the sonotube?
2) Do I need any other speaker materials besides the Hypex HS200 plate amplifier and the Tempest (like cables, etc.) to get this sub working?
3) Am I completely off the wall here, or do I have some clue about what I'm doing?
Any responses (especially to the third question) would be most appreciated.

 

[John Parris]

Question 1: Not sure about sonotube demensions, but I think there's a serious typo in your post: Should be 230L rather than 330L. BIG difference there.
Question 2: All you should need is the tube itself, 3/4" (somewhere around that) MDF for the endcaps and bracing, all the proper glue and tools, the driver, the amp, and cabling. Shouldnt need anything "special" otherwise.
Question 3: Good of you to do your homework... I think the Low Q sealed alignment from Adire will provide you with a really outstanding sub for music (particularly jazz). Should be the most cost-effective solution for you.
Here's a question for YOU: Can I come over and listen to some Victor Wooten or Stanley Clarke when you finish?

 

[Peter_A_M]

1) Adire recommends a net 230 L cabinet. If that were the gross volume, I'd just use the 31" sonotube. However, the volume of the recommended cabinet in the Sealed Tempest guide is close to to 330 L (330,000 cc), if I've done my math right, and thus I'd have to use a 45" long sonotube. It leads me to believe that that 100 L difference is made up in the polyfill stuffing and the displacement of the endcaps and bracing, but then again, I'm still new at this. :b
2) Does the cabling come with either the amp or the driver? If so, I'll order the parts second-day air right now and save myself the unneeded anxiety.
3) Yeah, I took a look at the "Future and current DIYers" thread, had a few laughs, but I know how annoying it is to be asked questions that would take only a few minutes of searching to answer.
I don't have much Victor Wooten or Stanley Clarke, but if you want to listen to some Coltrane, Wes Montgomery, Beethoven, or Bach's organ works, I'd be more than happy to have you over.

 

[warrick]

Peter,
The measurement from the Sealed Tempest Applications are external dimensions and take into account the bracing inside the cabinet thus a net volume of 230 litres
You will need a sonotube 36" depending on the exact volume of the Tempest and the thickness of the end caps.
You can use Brian Hepler's Nifty Program (ZIP file) That Calculates Everything Needed To Build A SonoSub
I did use this to calculate the exact length of my tube
Warrick

 

[Eduardo]

Peter, I am still working on my sonotube, 3 months and counting. Not becuase of difficutly but time. Anyways a few other items that you might want to consider; terminals for sub and/or amp, spikes for bottom of the base, hardware to attach the legs.

Here's a question for YOU: Can I come over and listen to some Victor Wooten or Stanley Clarke when you finish?

John - Someone turned me on to Victor Wooten a few weeks ago. He is amazing. I listened to Bella Fleck but never knew he was so talented. I highly recommend his album 'Show of Hands'

 

[Peter_A_M]

warrick,

That program was very nifty. Many thanks for the link.

On the actual sonotube material, I'm having a hard time finding sonotube, but I can get a 24" diameter section of black corrugated plastic tubing cut to any length for free. Is it acceptable to use any tube material of similar dimensions, or is there something inherent in the sonotube material that makes it ideal for subwoofer applications?

 

[warrick]

Peter,
Have you been to the conrete distributors,
I found mine at a paper tube company, you know the ones that make postal tubes just bigger.
I have not heard of anyone making one from plastic but as long as it is thick enough not to be flexable it may work fine.

warrick

 

[Peter_A_M]

OK, after doing some searching, I found a picture of this plastic pipe on the Link Removed's webpage. Apparently this sort of pipe is used pretty often in agricultural drainage, and from my own experience with the pipe, it's most likely much sturdier than sonotube.
Unless this pipe will produce a lower quality sound than sonotube, I think I'm going to go ahead, order the materials, and begin construction. Thanks for all of your help.

 

[Ron D Core]

One thing you should think about it how the pressure in a sonosub is presented to the tube. It is much like magnetic flux along a linear axis. It pushes out in all directions perpendicular to the tube's surface and the force is evenly spread throughout the entire surface. So the tube will not flex at all. I even tested it by making a sonosub with cement walls and another as everyone else builds them and they sounded exactly the same (granted the non cement one jumped around alittle). I installed 500' of that 18" irrigation awhile back and I can tell you it will be a huge ordeal to work with.

 

[Peter_A_M]

Ron,

I've forgotten most scientific principles since high school physics, but I still understand for the most part what you mean. However, I can't imagine this polyethylene pipe would flex under any normal operating condition. Perhaps we aren't thinking of the same tubing? I just brought up a length of 8" polyethylene pipe that was laying around the yard, and no matter how hard I push or pull against the inner or outer walls, I can't bend the pipe at all - it's unbelievably stiff.

My primary concern with using polyethylene pipe rather than sonotube is that the natural resonance of polyethylene will have an adverse effect on the final sound quality. If this is in fact a problem, I suppose I'll just use a sonotube and reuse the same size endcaps, legs, etc.

 

[ChrisAttebery]

Peter,

One thing you MIGHT be overlooking is how you will attach the end caps to the tubing. I don't believe poly glues very well. I don't remember for sure though. Ask the place where you will be purchasing it.

My brother made a pair of subs out of 12" pvc irrigation pipe. They sounded pretty good.

It can't hurt to try it out.



Chris

 

[Patrick Sun]

Guessing aloud, perhaps the plastic pipe might make a hollow sounding sub.

 

[Peter_A_M]

Chris,

Thanks for the input! I'm sure I have some super-adhesive around the house that can glue anything to anything, but I never considered that point. I guess I'll find out in a few days whether it'll work or not.

Patrick,

That's what I fear most. To experiment, I spoke into the tube with both ends open and it indeed sounded hollow. I then placed one end of the tube on the ground, spoke into the open end, and, to my delight, it didn't sound hollow at all. My guess is with both ends covered with MDF, the tube will sound better still. If worse comes to worse, though, I'll use some material to acoustically treat the tube or just make an effort to buy sonotube. Either way, making my own speaker should satisfy my mild audio addiction for a little while (well, I hope, anyway).

 

[Ron D Core]

Yeah it wouldn't hurt to try it, but I don't think it would sound any different than the standard sono material. I still think it wouldn't be worth the hassle of ordering it and having to cut it right, cover it and build it. If your using a Tempest, then you will need no less than 18" of diameter. As you have found out, that stuff is not very flexible, if your tube isn't perfectly round, which they never are after being strapped tightly to the semi trailer, you will have an hard time getting the endcaps into the tube tightly. And it will take a backhoe to smash it down to get it round (I know this) But if you do decide to go that route, just remember that you will need to cut it exactly between the ridges since the ridges are hollow and glued to the smooth pipe in between them. Its fairly thick in those larger diameters, I always cut the stuff with a DeWalt gas powered partner saw (fun but sloppy).
On another note, I wouldn't worry about it sounding hollow, since youll want to line it with some fiberglass insulation anyway.