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Re: The Most Powerful Subwoofer in the World [message #47996 is a reply to message #47993]

Sat, 15 October 2005 07:48

Wayne Parham
Messages: 18786
Registered: January 2001

Illuminati (33rd Degree)

The reason for the response ripple is the front chamber is larger than 20 liters. Front chamber volume is actually about 30 liters on this model. I'm happy with the response that provides, but it could be made smoother if the front chamber were reduced to 20 liters. I think you recall discussions about this between you and I in the past.

I use fill to reduce the front chamber volume, and without fill, it's 40 liters. When the front chamber is 40 liters, response is similar to the LABhorn. It's fine that way, but by reducing the front chamber, the ripple is reduced. The magnet sets the limit of depth for the chamber, but volume reduction can be done by displacing some space in the front chamber using filler material or panels. It's pretty easy to get front chamber volume down to 30 liters, but going smaller than that requires more attention and difficult fill shapes.

See the comparison of response curves with various front chamber sizes:

12π basshorn subwoofer with 20 liters of front chamber volume12π basshorn subwoofer with 30 liters of front chamber volume12π basshorn subwoofer with 40 liters of front chamber volume

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Re: The Most Powerful Subwoofer in the World [message #47997 is a reply to message #47996]

Sat, 15 October 2005 07:58

Walt
Messages: 16
Registered: May 2009

Chancellor

Yes, I remember the discussions. I think we can be very happy with this result. Your original idea was to use a front chamber of 50 litres which would have caused a reasonably big dip. I think now the 12pi response is very nice.

Still I would like to know if the dip around 40Hz is just as big as with 1W as with 1600W. If that is the case there is no limitation due to x-max in this 12pi design.

Best regards,

Walt

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Re: The Most Powerful Subwoofer in the World [message #47998 is a reply to message #47997]

Sat, 15 October 2005 08:18

Wayne Parham
Messages: 18786
Registered: January 2001

Illuminati (33rd Degree)

The dip is present at the same amplitude at all power levels. I am compiling all the information now to be placed on the website. Excursion isn't an issue - I even ran several sweeps starting at 10Hz at outrageous power levels and there was no mechanical interference at any power level. The limiting factor is thermal, not mechanical. The system runs into compression before suspension travel is exceeded. And failure is always due to thermal stress, which is why the heat exchanger is so important to this design.

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Re: The Most Powerful Subwoofer in the World [message #48001 is a reply to message #47994]

Sat, 15 October 2005 09:26

Leland Crooks
Messages: 212
Registered: May 2009

Master

I'll be there. You got my audio jones riled up worse than it was. I have a plan

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Re: good one [message #48007 is a reply to message #47986]

Sat, 15 October 2005 14:24

Bill Martinelli
Messages: 677
Registered: May 2009

Illuminati (1st Degree)

nice job, glad it worked out well for you

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Re: The Most Powerful Subwoofer in the World [message #48013 is a reply to message #47986]

Sun, 16 October 2005 08:12

Shane
Messages: 1117
Registered: May 2009

Illuminati (3rd Degree)

Wayne, thanks for designing a pro-sub that those of us who can't necessarily get the marketed stuff can build and use. There were a lot of times when I was gigging in the "bar band" that our homebuilt subs just took a header because of design flaws and thermal breakdown. A couple of the 12 Pi's with a couple of 1000W amps sounds like it would work very well! When you're up and ready to put out the design, whether kit or assembled, I'll be sure and let all the struggling musicians I know find out about them.

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Re: The Most Powerful Subwoofer in the World [message #48014 is a reply to message #48013]

Sun, 16 October 2005 08:18

Wayne Parham
Messages: 18786
Registered: January 2001

Illuminati (33rd Degree)

The design is completed so let everyone know. If they want the biggest and best, this is the one to have. But it is very large, not really something I think most bar bands would be interested in. It's more for outdoor concerts and festivals, stuff like that.

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Re: The Most Powerful Subwoofer in the World [message #48019 is a reply to message #48014]

Sun, 16 October 2005 13:55

Shane
Messages: 1117
Registered: May 2009

Illuminati (3rd Degree)

You would be surprised. We used to run two cabs that were about the size of the 12 Pi that had two 18" Widows in each cab. One cab was on the bass and one on the kick drum then EQ'd to just produce those nice low notes. It's not always about volume, but about the ability to produce the low end thump that makes the people in the front row want to pee. LOL!! We also played outdoors a lot in the summer time. If the soundman's doing his job it doesn't have to be ear splitting loud to get the job done.

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Its a releif, [message #48025 is a reply to message #48019]

Sun, 16 October 2005 20:26

Mike.e
Messages: 471
Registered: May 2009

Illuminati (1st Degree)

Its a relief to hear a nice overall bass response rather than exagerrated midbass with nothing below 60hz!

- I went to a dnb gig once,that used an obscure KVAUDIO system with multiple direct radiator 18"s in a 7ft x 40ft x 20ft room,and the SPL at ~45hz was insane-it was actually uncomfortable, and as loud as inside a car!

Mike.e

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Re: The Most Powerful Subwoofer in the World [message #48026 is a reply to message #47998]

Mon, 17 October 2005 12:24

Walt
Messages: 16
Registered: May 2009

Chancellor

I followed the 12pi horn from the beginning. I also did so with the LAB-horn. I never quite understood why there wasn't paid more attention to the 'dip' a single LAB-horn shows. To me it seemed a little more back chamber volume would offer a flatter response Although the 12pi frontchamber is still a little large the reponse for a single 12pi seems very usable.

I think A/B testing with music has to be done to determine whether the push/pull arrangement pays off. But in theory it is a good thing so why not use it? Same with the heat exchanger but I have to agree with Tom that sine waves and music are a world apart. Also in a shootout on the Speakerplans forum the LAB-horn did very well on sines but there where cabinets that sounded more musical.

As to the statement of 'most powerfull subwoofer in the world' that depends strongly on the frequency range. Here in holland 4x Punisher were way louder then 2x LAB-horn. Perhaps not the real sub range but things like shaking eyeballs and causing breathing problems they did very well. As for power on these things, I know a guy who puts a single channel of a RAM BUX 5.0 on a 4-ohm Punisher, not bad for only a single 12" driver