Tuba subwoofer design for 6" or 5.25" driver

[TheGreatGazzoooo]

A 6" can certainly hit 20Hz, but don't expect significant output. Because of the lack of surface area, it will have to have monster excursion to move enough air. The Tang Band 6" has quite a bit, and can do 40Hz, but is still quite volume limited.

Also, how do you plan to build a spiral like that? I would imagine you'd have to go with fiberglass.

I was going to use a long 9 foot strip of 1/8inch plywood and use a steaming technique to bend it, but for the quick test to understand whats happening with the sound I was going to use a 9 foot long rigid cardboard strip (that has the density of cardboard concrete tubes) and glue the spiral into different configurations ranging from horn length and mouth size while testing the audio each time before I change the horn length or mouth size. Then compare my results to understand how to optimize that type of design before I build a real wooden one. I would still like to play with the spiral idea for my own knowledge but I have a fairly busy schedule now and as I said in my last post this test mock up at 14x14x14 is just to big for my project. Bill is probably rolling his eyes since he has the expertise to understand what exactly is going on. But I like to experiment and crunch the data even if it is all for not I will learn the basics of what is happening with the sound.

[Radian]

With a spiral, flare-rate and horn length become simultaneous parameters.

[TheGreatGazzoooo]

So as a true horn not so great but check this configuration out that I just came across that does use a spiral, well many spirals, this was an award winning design for best sounding speaker. It's got me rethinking my 5.25 driver. hahaha!

I'm kidding, I will still be moving forward with the vented cabinet.

http://blogs.msdn.com/b/andrewdelin/arc ... 07944.aspx

[DJ Higgumz]

Have you thought of a bandpass design? They get loud but have a thin frequency band

[TheGreatGazzoooo]

Have you thought of a bandpass design? They get loud but have a thin frequency band

Yes I know bandpass very well. I worked in a car stereo design and wood shop business for 6 years that designed nearly all bandpass we used either single or dual bandpass designs. We designed and built nearly all of Clarion, Kenwood, Phoenix Gold, and Orion's sub cabinets in the mid to late 90's. Imagine 5 guys in a shop doing runs of 100 hand made bandpass cabinets! That's how it was done in the 90's! We also designed and built all of their in store display units.

Bandpass is on the large side for my project since bandpass requires nearly the same air volume in the both sides of the driver. Bandpass can sound good but it is very specific to certain driver specs and perfect cabinet design to make that happen. Most drivers that I have dealt with in bandpass seem to excel at certain frequencies but produce anything but a flat decent sounding response. However I remember a handful of designs we made with specific drivers that stood out as great sounding bandpass subs. Looking at what Bill has in the T18 and the Home Theater Tuba (36 inch wide version) The responses are so loud and fairly flat so I think it must sound great. This is the reason I came to this forum to try to build worlds smallest and loudest horn sub which we now know is not possible!

On a different note if I ever have the space for such large subs I will be buying some plans for the T18 or home theater tuba and trying it out! Currently I have a 14x14x14 vented sub that does my home theater fine. It isn't perfect though!

[SirNickity]

Bill is probably rolling his eyes since he has the expertise to understand what exactly is going on. But I like to experiment and crunch the data even if it is all for not I will learn the basics of what is happening with the sound.

You gotta learn somehow. I'm right there with you. Sometimes failure, even predicted failure, is still very educational. If you do build this, I would love to see how it turned out -- good or bad.

[Bill Fitzmaurice]

Sometimes failure, even predicted failure, is still very educational.

But when others have already trod the same path and you can learn from their experience there's no need to fail in order to learn. Reading is a lot less expensive too.

[SirNickity]

Understood and agreed, but .. if you like to build things, that's just a neat thing to build. Ultimately fruitless? Maybe so, but so what? If you know that going into it, you get some experience working with materials, and you can see first-hand why it's not the best design. I would be curious to hear what it sounded like, even if I knew ahead of time I wouldn't prefer it over a "good" design. (Not enough to build it myself, but I would absolutely take the time to check out a YouTube clip.)

You're a briliant guy, and very efficient. I'm not trying to argue your point (I can't -- it's valid), or change your mind about anything here. BUT, there is another equally valid opposing viewpoint. Some folks appreciate the journey as much or more than arriving at the destination. Your experience is hugely valuable, and you can see he took your advice, so don't feel like you're preaching to a brick wall. Curiosity can't always be squelched with logic, though.

[BrentEvans]

But when others have already trod the same path and you can learn from their experience there's no need to fail in order to learn. Reading is a lot less expensive too.

Not always... visually oriented and action oriented learners usually need to experience the failure to internalize it. Some people will learn more by doing than they ever will by reading.

That doesn't make it any less expensive.

[Gregory East]

Good point, some people learn by doing.

[biodad]

Myself, I am very open minded and enlightened because I believe literally everything I read and hear, except from experts like Mr Fitzmaurice.

However, in the process, I have toasted six 18's, three 15's and two lab gruppens. Who needs the truth and facts when a wallet full of scrilla gets you there, albeit slower. . .

[Gregory East]

Us book learners call that "the hard way"