Vasubandu's Sub of Insanity

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Vasubandu
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Vasubandu's Sub of Insanity

#1 Post by Vasubandu »

I am relatively new to all of this, and am just starting on a subwoofer that may or may not make any sense.

In an nutshell it is a a round column or tube subwoofer. It will be 6 feet tall and 36 inches in diameter and have 2 opposing SI HS-24 Mk II drivers. I am told that I am doing this backwards by starting with the enclosure, but it seems to me that it should be possible to do everything in either order. The size is dictated by the drivers. It will be ported, and in a vented setting, they are rated for 16-20 cubic feet each. My column will have just over 40 cubic feet raw and a little under after the two .75 cubic foot drivers.

I was just directed to Bill's Tuba plans, and the THT low profile version looks a lot like my idea, only a bit smaller and square. So at the moment, I am trying to look at the plans I just ordered and see if they could be adapted to a round configuration. I want to go round because I cannot put it in a corner with my room, and something round looks smaller than something square. Not sure yet if the HS-24 will work with it and and whether it can use 2 drivers. This discovery has a lot of things in flex and I look forward to getting some advice about what to do.

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Tom Smit
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Re: Vasubandu's Sub of Insanity

#2 Post by Tom Smit »

What you could do is build the THT according to the plans, and then add the sections needed to make it appear as if it were a cylinder.
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Re: Vasubandu's Sub of Insanity

#3 Post by commander_dan »

Tom's idea is good although the cab will end up a lot bigger than it should.

The designs are much science and effort on Bills part. Messing with will certainly detract from their performance, do so at your own risk.

What are you using the sub for, assume home theatre?
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Bill Fitzmaurice
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Re: Vasubandu's Sub of Insanity

#4 Post by Bill Fitzmaurice »

It should take less than a minute of looking at the plans to see why making it round isn't possible.

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Re: Vasubandu's Sub of Insanity

#5 Post by 88h88 »

Vasubandu wrote: Thu Feb 15, 2018 5:52 pm ...and I look forward to getting some advice about what to do.
The thing to do would be to build a THT and watch movies in the dark. The speakers you're describing (or at least trying to I think) are Sonotube subwoofers?
4xOT12s, 2xT39s@22", TTLS@18", 2xT60@18"

Vasubandu
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Re: Vasubandu's Sub of Insanity

#6 Post by Vasubandu »

Thanks everyone. The thing is this is more an experiment than a subwoofer. I want to actually hear what different permutations sound like, and I want to be able to easily mix things up, I realize that a lot of this at east in theory can be answered with equations and software. I also have a nagging suspicion that driver size has increased over the years, but enclosure size has not. That has me wondering about the volume requirements for subwoofers, and I seem to see a lot of ported subs that cannot have the volume they should. So I want to see firsthand the effects of volume. I can diminish the volume the sub with calibrated bags of sound.All this may make sense to no one but me, but I expect to learn a lot.

I should say that enough people have told me that Bill is a genius for me to believe it. I he cares to share any thoughts along the way, I certainly would give the the greatest consideration. Maybe he would understand the experiment idea.

Bill I do see why it would not be possible to make your design in the round, but I am not sure that means it could not be adapted. That would certainly be a complicated endeavor. If I just wanted an excellent subwoofer I would follow it.

88h** it is not a sonotube. It is made of curved plywood 5/8 ihick thick. I never could make peace with the idea of a cardboard subwoofer no matter how sound it might be.

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Bill Fitzmaurice
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Re: Vasubandu's Sub of Insanity

#7 Post by Bill Fitzmaurice »

Vasubandu wrote: Fri Feb 16, 2018 9:49 pm I also have a nagging suspicion that driver size has increased over the years, but enclosure size has not. That has me wondering about the volume requirements for subwoofers, and I seem to see a lot of ported subs that cannot have the volume they should.
They don't. Google 'Hoffman's Iron Law'. Physics dictate that to go low with high sensitivity a cab must be large. WAF dictates "I don't want a big subwoofer thing in my living room!" Guess which wins in the marketplace?

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Re: Vasubandu's Sub of Insanity

#8 Post by Vasubandu »

Bill Fitzmaurice wrote: Sat Feb 17, 2018 8:28 am
Vasubandu wrote: Fri Feb 16, 2018 9:49 pm I also have a nagging suspicion that driver size has increased over the years, but enclosure size has not. That has me wondering about the volume requirements for subwoofers, and I seem to see a lot of ported subs that cannot have the volume they should.
They don't. Google 'Hoffman's Iron Law'. Physics dictate that to go low with high sensitivity a cab must be large. WAF dictates "I don't want a big subwoofer thing in my living room!" Guess which wins in the marketplace?
Thanks for the response and the verification. That was very helpful.

OK if they don't wouldn't there be advantages to actually making the enclosure an appropriate size? There is plenty of science that a round object is perceived as being smaller than a square object of the same volume.,which let me to thing that the WAF factor might be overcome with a round column subwoofer. That would require starting over in many respects unless something could be borrowed from the SVS round subs. I am not trying to reinvent the subwoofer, just having some fun with a question. Fortunately, I own the basement where the system is and after 30 years, my wife has learned to roll her eyes and live with my projects.

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Tom Smit
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Re: Vasubandu's Sub of Insanity

#9 Post by Tom Smit »

Vasubandu , rather than building a cylinder you could dress/decorate the sub to become part of the "artwork".
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Bill Fitzmaurice
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Re: Vasubandu's Sub of Insanity

#10 Post by Bill Fitzmaurice »

Vasubandu wrote: Sat Feb 17, 2018 1:35 pm wouldn't there be advantages to actually making the enclosure an appropriate size?
Speaker manufacturers are in the business of selling speakers. They sell what people want, what people want is speakers that are small. If, instead of accountants, engineers determined what was sold Bose would not exist.

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Re: Vasubandu's Sub of Insanity

#11 Post by Vasubandu »

Bill Fitzmaurice wrote: Sun Feb 18, 2018 9:17 am
Vasubandu wrote: Sat Feb 17, 2018 1:35 pm wouldn't there be advantages to actually making the enclosure an appropriate size?
Speaker manufacturers are in the business of selling speakers. They sell what people want, what people want is speakers that are small. If, instead of accountants, engineers determined what was sold Bose would not exist.
In that case, we need to make our own the way that they should be. I am assuming that you have cut no corners in your designs. It sure does not look like you have.

My the way, does the low profile need to be in a corner. If my wife complained, I could just say, "would you rather have a giant tube?"

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Bill Fitzmaurice
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Re: Vasubandu's Sub of Insanity

#12 Post by Bill Fitzmaurice »

It only needs to be close to a corner for full sensitivity, which 10 out of 9 users don't need anyway.

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DJPhatman
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Re: Vasubandu's Sub of Insanity

#13 Post by DJPhatman »

Want to win the WAF war? Build a THT LP, dress it up like a bench seat, have SWMBO sit on it. Kiss her with the most passion that you can humanly muster, while playing the cannon fire from the 1812 Overture! :twisted: :hyper: :twisted: :fruit: :twisted: :mrgreen:
I know money often seals the deal, but seriously, quality is an investment, not an expense... Grant Bunter
Accept the fact that airtight and well-braced are more important than pretty on the inside. Bill Fitzmaurice

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