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Romy the Cat wrote:

Guys, I am not looking or care about the design specifics but rather looking for some fresh idea and inspirations that would make me to think further. You see, if I shut down Macondo and measure just ULF channels then I have just little bump at minus 6-8dB around 23Hz-33Hz and it is it. For this I pay with two large woofer tower, amps, crossovers, cables etc…   too much mess and complexity for such a small benefit.  I know, I know. I understand that produce this “bump” at 25Hz with relatively low distortions there is no other ways then to go for large and expensive solutions. Still, I always feel that smart and elegant and better than expensive and I would like to find a smarter way to get my bump.

Among all interesting alternative ideas that I have there is one that makes me to think a bit out of shoe box. Of cause I could try that propeller woofer that has so much publicity a few years back. It is small and it reportedly gives low bass.

http://www.rotarywoofer.com/

it is $25K per woofer and I need two, it is absolutely not know to me sound and I have null ability to product how that thing might sound. So, unless the propeller woofer people have some kind of framework that would let people like me to do my home trail I think what they do will be more like internet freak show instead of being a practical and viable solution. I also concern that being located in the same focal location with the rest of speakers the rotary woofer might be too mechanically noisy. I do not mention that my Koshka would for sure object if in the middle of her room I install two cat-chopping machines…

Ok, returning back to my out of shoe box idea. What I would like to have idly would be a properly sounding Sunfire True Subwoofer Junior.

http://www.sunfire.com/productdetail.asp?id=10

This thing is a beauty itself. It is 11 by 11 inch small, it is has own amp inside and has own signal-sensing switch the turn itself on, it able to produce stunning acoustic pressure that can literally bring house down. This is a dream come thought for my placation. There is a small problem with this Sunfire prettiness, the same problem that is very common to anything that Bob Carver ever touched – this True Subwoofer sound like shit. I would not call that crap the this True Subwoofer out as bass but it rather it is some kind of generic pressurization of air and this pressurization has very little relevancy to what is being played.

It is not the point however. No one willing to employ the Bob Carver title fart machines but the idea to get all the bass that I need for my 25Hz bump from one small driver and one sq foot of spare I find is very elegant. The question is: how to do it? How to fuck up to rules of physics and to accomplish what I need to accomplish?

The high exertion of the small driver doe not bother be in my specific application. I need to care just one octave at my 25Hz bump, so all normal problem associated with high exertion are not applicable in there.  The problem with one sq foot ULF section, high power and high exertion is that when woofer is pushing or pulling there is not enough buffered space inside the enclosure, so the compressed air in the back of the sq foot ULF produce tremendous amount of distortions. Ok, but how about if we somehow change the rule of the game and insert inside of this small ULF section some kind of equivalent of Black Hole. Now as the woofer compress the air inside of enclosure the Black Hole would instantly and infinitely to consume that pressure, converting my one sq foot ULF section into infinite baffle. The problem with Black Hole is that when a driver goes out then in order to be infinite baffle the Black Hole shall give instant birth to infinite matter, to become sort of equivalent  of Supernova.

Two much fantasy? Not necessarily.  Let to think in very practical trims. I need some kind of solution that would consume and produce air in my hypothetic one sq foot ULF section. I can’t consume or produce matter but for sure I can transfer it. A friend of mine what I was dumpling all of it to him suggested me convert pressure to temperature. He suggested that if the speaker inside would be partially filled with some kind of liquid or gas that can change temperature from pressure than I might accomplish what I am looking for. I do not think that liquid would do it as it has not fast enough transfer function between pressure and temperature. Pretend that a sealed speaker is filled with gas that that has very fast transfer function and the signal besides driving the woofer power also a circuit that dispatch electrons or ions into the gas (remember a vacuum tube?). The gas has ability to change density, or temperature, or anything after being exposed to ionization. So, what we do is to figure out the delay time the driver need to get momentum and shoot electrons/ions into the gas behind the woofer, assuring that the woofer in falling into collapsed space behind it. As woofer need to go back we reverse polarity on our speaker cathode and suddenly the space behind the woofer behind begin to build pressure (along with drop of temperature for instance). I think we are very far here from Black Holes and Supernovas and with popper engineering support something like this might be experimented with…

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