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Variation on a Theater 4pi [message #38758] Mon, 21 October 2002 13:36 Go to next message
DRC is currently offline  DRC
Messages: 169
Registered: May 2009
Master
Okay, I've settled on the Theater 4pi because I want to use the Delta 15, and I like the efficiency. Since I'm going to use the Martinelli horns, I'd like to stretch the height (to get the horn to optimal height for seated listening), and decrease the width to keep the volume constant and get closer to the horn width. I figure 40Hx21.5Wx18D will do the trick.

That raises the question of where to place the woofer, and maybe the port. Since the horn will be sitting on top of the cab, I'm thinkin' it should come up quite a ways, but how far? Am I trying to maintain a certain distance from the woofer to horn, or some slighly but not terribly assymetrical arrangement on the cabinet face to distribute (not reinforce) resonances, or . . .?

There will be 3.5" to either side of the woofer, as opposed to 4.5" stock.
So do I want the woofer edge to be 3.5", 4.5", 6" . . . .? away from the top of the 40" cabinet?

Do I need to move the port, or should I leave it where it is?

I assume starting with the stock 1k6@10db xover makes the most sense, since it's the same compression driver, even though it's a different horn flare.

Does any of this make sense? ;-)
Keep your ears and your mind open.

My 2 pesos [message #38759 is a reply to message #38758] Mon, 21 October 2002 16:01 Go to previous messageGo to next message
BillEpstein is currently offline  BillEpstein
Messages: 886
Registered: May 2009
Illuminati (2nd Degree)
Since I won't be replicating the Cyclops Gran Prix car with my 2 Pi's, I'm hoping someone will take up the challenge of putting Bill's Horn on a stand instead of just laying it on top like a Lox.
Hey Bill, how about a hardwood cantilever with brass hardware thingy to support the horn over the woofer cabinet. Adjustable in 5 planes and all that. How much could it cost?
Mr. Cope sounds like the John Beresford Tipton of audio.
Re: Variation on a Theater 4pi [message #38762 is a reply to message #38758] Mon, 21 October 2002 16:33 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18789
Registered: January 2001
Illuminati (33rd Degree)
Lots of people build four π Speakers just like you're describing, with Martinelli horns mounted on top. It's a popular combination. What I'd suggest you do is to move the midwoofer up towards the top of the cabinet and mount the tweeter horn on top, flush with the face. In this manner, you can keep the spacing between them the same, and the cabinet looks very good that way as well.
Till - I don't get it [message #38763 is a reply to message #38759] Mon, 21 October 2002 17:08 Go to previous messageGo to next message
DRCope is currently offline  DRCope
Messages: 160
Registered: May 2009
Location: Brooklyn, CT
Master
Okay, I looked up JBT, but I don't get it.

Whaddya mean?

Confused in CT
Keep your ears and your mind open.

Re: My 2 pesos [message #38767 is a reply to message #38759] Mon, 21 October 2002 19:11 Go to previous messageGo to next message
bmar is currently offline  bmar
Messages: 346
Registered: May 2009
Grand Master
Sounds cool. I have a few anti loxing ideas kicking around but i'm up to my eyeballs in sawdust right now. all current winter projects have been rescheduled to summer projects, but some day i'll work up a thingy or two for ya. what if we "float" the horn on top of the cabinet with some opposing pole neodinium magnets? na, it'l mess with my karma
Re: Till - I don't get it [message #38773 is a reply to message #38763] Tue, 22 October 2002 01:42 Go to previous messageGo to next message
BillEpstein is currently offline  BillEpstein
Messages: 886
Registered: May 2009
Illuminati (2nd Degree)
Back when men were Broderick Crawford and TV was black and white.....
One of my favorites, next to "Man and the Challenge"NT [message #38775 is a reply to message #38773] Tue, 22 October 2002 05:04 Go to previous messageGo to next message
Garland is currently offline  Garland
Messages: 269
Registered: May 2009
Grand Master
nt
HMMMMMM [message #38776 is a reply to message #38758] Tue, 22 October 2002 05:42 Go to previous messageGo to next message
JLapaire is currently offline  JLapaire
Messages: 156
Registered: May 2009
Master
Sounds VERRRY familiar, Dave, now where have we seen tall Theater 4s lately?
And why was Till thinking you were a millionaire? Did he get a look at all that beautiful AudioNote gear in your listening room?
Will they be done by the 3rd?

Regards,

John

Re: HMMMMMM [message #38778 is a reply to message #38776] Tue, 22 October 2002 07:22 Go to previous message
DRC is currently offline  DRC
Messages: 169
Registered: May 2009
Master
Gee . . . I can't remember - oh yeah! Hendrix live at the Fillmore East playing right in my freakin' sound room - that's where! So this is all your fault, John! (Mike P. was fairly impressed as well, clearly.) I just got a wild notion to try a really efficient, (partially) horn-based system.

I have no idea what Till means. I found explanations on the Web before I made my "duh . . .huh?" post, and I still don't get it.

Mine will be a bit different from yours and Garlands since I'll be using the Martinelli/Woodhorn flare on top of the cab. I've signed up for siblings (sourced from same piece) of the bird's eye maple ones on the woodhorn site. Works of art, I tell ya!

Bill M. is workin' hard to get a pair of horns ready so we can hear 'em at the meeting. I'm delaying my horns so we can all get a listen on 11/3. I'd love to run 'em through your Twos, and Doug Piccard will be hauling some big-a** EV bass bins up from PA as well. Should be really cool. My cabs won't be remotely done by then. For one thing, I have no idea what I'm doing in the cabinet-building realm. ;-)
Keep your ears and your mind open.

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