Design up for discussion.

**Mongrel714** · **06-25-07, 08:23 PM**

Hello all!
I took a trip up to Savanah GA. this weekend to meet with some family, as usual, in the back of my mind, that endless loop of, Subs, watts, speakers, SPL, MDF, DB, What do I buy next?....Will this work??..played un interupted, and everything I looked at made me wonder, how can I use that in a design? Well, one pedestrian suspension bridge over hwy 95 caught my eye, so While my family slumbered in the hotel room, I cranked up Corel Draw and came up with this design, Now this is open for discussion and suggestions, it may not work at all, but it looks pretty cool so lets here your ideas about this sub design, Maybe we can come up with the H.T.S. X-treme Sono SUb!!

**Otto** · **06-25-07, 08:50 PM**

Well, Mongrel, I must say that while I honestly don't know how well your designs will work for speakers, I really appreciate your ability to link one design to another -- the way that you incorporate ideas from all around is pretty cool. You just might be one of those guys that comes up with something new and different, and people will say "why didn't I think of that!?!?!"

Good luck!

**bonehead848** · **06-25-07, 08:57 PM**

that is pretty freaking awesome imo, the only problem I could see is trying to incorporate that into a ht. Seems like it might stick out just a bit

**Sonnie** · **06-25-07, 09:09 PM**

This could be cool indeed. I'm assuming you hang it from the ceiling. You would definitely have to get location down prior to mounting.

**Mongrel714** · **06-25-07, 09:57 PM**

Yeah Sonnie, you could hang this from pretty much anywhere you could get a solid attachment, and Bonehead, it def would stick out, which maybe would be a good thing, IF the wife would aprove!! Man Otto, it would be cool to design that next big thing. I'm not sure the side ports would be quiet enough but I have another idea I'll try to draw up tonight.

**Mongrel714** · **06-25-07, 11:18 PM**

Heres my idea for a "Radial" (??) port design, This prob has been done before, kinda like a jet engine.
Hmmmm, looking at this, the "Cone" should extend into the main interior enclosure.

**Chrisbee** · **06-26-07, 02:59 AM**

Clever chap! My worry about suspending a sub would be the reaction forces from the driver. You might get very poor transient response if the sub recoils like a real big gun on Master and Commander cannon shots!

I like the radial port (a lot) though it might be difficult to obtain the required area for tuning unless it becomes very narrow indeed. The tuning of the area to match the length have become variables of enclosure size and difference between the inside and outside diameters of the nested tubes. The software to easily design one is hopefully already going round and round in somebody's head. Pi x R1^2 - Pi - R2^2 x L .

The shell which forms the port's outer edge could help to isolate coloration from the tubular enclosure inside. Steve Callas should be designing LLTs around this idea to avoid those huge ports. We've lost enough small children and Newfoundland pups to his oversized port dimensions already.

I think you need a nice curve at the outer edges of a much larger and longer cone. Where the port begins and the enclosure ends could be a difficulty. Somebody should build a prototype immediately to prove the concept!

This concentric port idea should have been worthy of a patent or at least a registered design if it is really new.

**Mongrel714** · **06-26-07, 04:04 AM**

Chrissbee, Yes, I worried about the "push-pull" effect on the enclosure, But I beleive with the proper cable attachment and anchoring of the framework it would be solid, would the speaker recoiling cancel out some of the sound waves??

I will have a revision on the radial port in the morning!

**Chrisbee** · **06-26-07, 04:15 AM**

Quote:

Mongrel714 wrote:

Chrissbee, Yes, I worried about the "push-pull" effect on the enclosure, But I beleive with the proper cable attachment and anchoring of the framework it would be solid, would the speaker recoiling cancel out some of the sound waves??

They could well indeed cancel out! As anyone who has built a line array IB sub in a flexible wall can confirm.

Quote:

I will have a revision on the radial port in the morning!

We'll look forward to more of your clever ideas.

**Mongrel714** · **06-26-07, 05:01 AM**

Rev 1
6 AM, have to get back to sleep! after all, I am on vacation!! lol, thanks for the kind words Chrissbee!

**Chrisbee** · **06-26-07, 05:17 AM**

It's a subwoofer not a cannon!

**Chrisbee** · **06-26-07, 05:33 AM**

Inverted would be more stable. The heavy driver wold then be at the bottom like the SVS cylinders. Short feet would secure the correct height from the floor.

**Bob_99** · **06-26-07, 09:00 AM**

For whatever it's worth, wouldn't it be better to extend the inner tube all the way to the bottom to anchor it and put openings on the side of the inner tube at the bottom?

Bob

**Mongrel714** · **06-26-07, 10:27 AM**

I'll draw up some fabrication plans today and maybe we can get some ideas on measurements for this puppy, Hmm Chrisbee, a Sonic Cannon? Why, with a Sonic Cannon we could take over the worl...O.k. I know, we have to use our powers for good...

The interior side fireing port openings may be something to think about and easier to construct, I'll have to let the experts here rule on that one, lets here it guys!

**FireWalker877** · **06-26-07, 11:40 AM**

Mongrel, that is a pretty cool idea! If you had an external diameter on the inside of 18" and an internal diameter of 19 on the outside, you would have almost the same cross-sectional area as a 6' inch port. However, there might be a problem. If you look at a 6" diameter pipe, the wall length is slightly larger than 18". Here we would have 116 total inches of wall in contact with the air. By no means am I an expert of the subject, but it might be that this huge increase in wall area would be detrimental. It would seem to increase drag, which would cause turbulence. Also, since the inside and outside walls would have different areas, you might experience even greater turbulence due to the air on the inside wall moving more quickly on the outside wall. (This could produce an eddying effect due to the inner wall being at a lower pressure.) I'm certainly not trying to on the design. I only stumbled on these things because your idea struck my interest. Perhaps someone with a little stronger background in aerodynamics can put my concerns to rest. I hope so! Otto is right, you may well come up with the next big thing!

**Mongrel714** · **06-26-07, 12:03 PM**

Yes there are definately some issues to figure out here, I would like to construct a scaled down version of this to start with, it would have to be substantial enough to get some good readings, I think the interior walls should be smooth, maybe not glass smooth but free of the seams the sonotube has. any ideas are welcome guys!

**Chrisbee** · **06-26-07, 01:10 PM**

Quote:

Mongrel714 wrote:

Yes there are definately some issues to figure out here, I would like to construct a scaled down version of this to start with, it would have to be substantial enough to get some good readings, I think the interior walls should be smooth, maybe not glass smooth but free of the seams the sonotube has. any ideas are welcome guys!

I'm not sure that with normal port velocity the port surface structure is particularly critical.

I don't like perforations in the outer wall of the enclosure. That would really produce some turbulence!

**Mongrel714** · **06-26-07, 02:41 PM**

Quote:

Chrisbee wrote:

I'm not sure that with normal port velocity the port surface structure is particularly critical.

I don't like perforations in the outer wall of the enclosure. That would really produce some turbulence!

When you say perforations, are you refering to the attacment to the interior tube? which would be 4-wooden (??) strips holding the tubes in position, which would be more like directional vanes running the entire length of the port.

**Chrisbee** · **06-26-07, 02:51 PM**

Bob_99 suggested what sounded like perforations. It was those I was referring to.

Your latest drawing shows flow from the driver to the great outdoors.

There is no net flow. More like a reciprocating air mass.

**Bob_99** · **06-26-07, 03:01 PM**

My apologies for not being clearer but definitely not perferations. More like have 'legs' extended to the bottom so the inner tube is secure.

Bob

**Chrisbee** · **06-26-07, 03:05 PM**

Aha! My apologies for misunderstanding your suggestion.

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