Variation on a 2pi theme [message #38737] |
Sat, 19 October 2002 12:20 ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
DRC
Messages: 169 Registered: May 2009
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Master |
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I'm nearly commited to making 40" tall Studio 2pi Towers using the 12" driver, and the 2002 compression driver mounted in a woodhorn 12" tractrix sitting on top. Should I move the woofer closer to the top edge of the cabinet, since there will be no tweeter on board? What change(s) do I need to make to the port given the change in woofer and cabinet volume? If I go 3/4 instead of 5/8, do I need to further adjust the port size, or just reduce the thickness at the port to 5/8? Keep your ears and your mind open.
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Actually, it's a three π [message #38739 is a reply to message #38737] |
Sat, 19 October 2002 17:22 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
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Wayne Parham
Messages: 18748 Registered: January 2001
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Illuminati (33rd Degree) |
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What you are describing is essentially a three π speaker. For example, a Thermionic Series three π uses an Alpha 12 and a PSD2002 in a 6 cubic foot box, tuned to 25Hz. A Theater Series three π is similar, but uses a Delta 12LF and a PSD2002. With each different model woofer, the box is tuned differently, appropriate for the motor's characteristics. If you use the Alpha 12, the box will need to be at least 5 cubic feet. So the cabinet size of the tower two would work pretty well, but the cabinet should be tuned a little lower. PiAlign recommends 5 cubic feet, which should be considered a minimum volume for that particular woofer. Other motors will have their own unique requirements for motor chamber, so it is best to match the woofer with an appropriate box. But it's pretty easy to do, and I think you'll be very pleased with your results. The system you've described sounds nice, and if you need any of the parts, we have all of them in stock. We have everything available from the midwoofers and compression tweeters to the horn flares and crossovers. You might find it easiest to purchase a three π kit in the "π Speaker Kits" section rather than to order parts individually.
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Re: Actually, it's a three π [message #38747 is a reply to message #38739] |
Sun, 20 October 2002 10:27 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
DRC
Messages: 169 Registered: May 2009
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Master |
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Wow! You really believe in full responses, Wayne! cool. ;-) Nearly as soon as I posted, I realized a 2pi didn't make a lot of sense for where I was going. I'm in what gets referred to around here as the"tube-friendly" camp, although I think a lot of us are actually in the SET-friendly camp, which is even more demanding and less forgiving than some of the PP tube amps. So power handling is not a consideration, but keeping the amp happy is. The less compensating I have to do in the xover, the better I like it, so flatter uncompensated response looks like a good thing. I'm going to use Martinelli horns w/PSD2002's. I'm thinking that I should be able to cross them over somewhat lower than the smaller flare on the face of the spkr cab allows. Does this make sense? Keep your ears and your mind open.
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Re: Dave, You always have to have the biggest Pi's on the block! [message #38753 is a reply to message #38751] |
Sun, 20 October 2002 18:22 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
DRC
Messages: 169 Registered: May 2009
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Master |
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Yer killin' me! I'm really just chasing the smoothest upper midrange, but the size is rather scary. May have to "back off to the Theatre 4's." ; -) Thanks for not saying, "What in heaven's name do you need more speakers for?!?"Actually the meeting's the 3rd. I goofed on the first announcement. I try to keep 'em on a Sunday. 10's! Yeah, now yer talkin'! Keep your ears and your mind open.
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Re: Now it's a four Pi [message #38754 is a reply to message #38748] |
Sun, 20 October 2002 18:31 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
DRC
Messages: 169 Registered: May 2009
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Master |
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Wayne, please send me the plans for the Theater 4's. I've heard Garland's, and they sound great. And no matter what he says, the 10's are out of the question. (At least as long as I live on the 3rd floor!) ;-) Thanks for all the info. Can't wait to build these babies! Keep your ears and your mind open.
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