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2 pi questions: [message #45514] Tue, 05 October 2004 01:24 Go to next message
tube_ee is currently offline  tube_ee
Messages: 5
Registered: May 2009
Esquire
How much wood is needed to build the 2 Pi and 2 Pi Tower speakers? What wood is recommended? I have 2 5x5 sheets of 1/2" baltic birch plywood that I bought for another project that could be pressed into service here, if it'll work.

Is there anyone in San Diego running Pi speakers and 2A3 amps that I could hear? 2 Pi's and Paramours would be ideal, but anything that would give me an idea about Wayne's "house sound" and low-power triodes would be welcome.

FWIW, I'm currently using the Paramours with 89-dB sensitive PSB Century 600s. While this combo isn't particularly dynamic (the PSBs aren't, regardless of amp), and it won't play super loud, it does enough right that my 40 watt Jolida integrated has sat unused for almost a year.

If I have to sacrifice what I like about my system, just to get some things that I'm not as concerned about, I'm not as interested. If I can keep the good stuff and help out the weaknesses, that's a good upgrade.

Thanks,
--Shannon

2 pi answers: [message #45516 is a reply to message #45514] Tue, 05 October 2004 08:02 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18733
Registered: January 2001
Illuminati (33rd Degree)

I think a lot of your questions can be answered best by letting you see the plans. If you'll send me your E-Mail address, I'll send them. They work great on low-power tube amps. I have 2A3 based Paramour amps myself, and the speakers sound very nice with them.


Re: 2 pi answers: [message #45518 is a reply to message #45516] Tue, 05 October 2004 11:39 Go to previous messageGo to next message
tube_ee is currently offline  tube_ee
Messages: 5
Registered: May 2009
Esquire
Thanks for the quick answers, Wayne. It sounds like the 2 pis are a good option for what I want to do, especially since I don't have the room or the bread for cornerhorns.

Could you send me the plans for the regular and tower versions?

Thanks,
--Shannon
tube_ee@yahoo.com

You've got mail! [message #45519 is a reply to message #45518] Tue, 05 October 2004 13:05 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18733
Registered: January 2001
Illuminati (33rd Degree)


I've got mail! [message #45520 is a reply to message #45519] Tue, 05 October 2004 14:53 Go to previous messageGo to next message
tube_ee is currently offline  tube_ee
Messages: 5
Registered: May 2009
Esquire
Thanks, Wayne.

You rock.

A few minutes with some graph paper and a ruler shows that I can cut the panels from the 2 5x5 pieces of 1/2" Baltic Birch plywood I have on hand. What effect will the 1/8" thinner wood have on the tuning? Will using this wood change the sound of the speakers, and if so, how?

I expect that the plywood will be more resonant than MDF, but what that means for sound I'm not so sure of.

Also, my cutting plan leaves me a 28"x14" piece of wood that could be used for internal bracing. What kinds of bracing have people used?

--Shannon

Miscellaneous information [message #45523 is a reply to message #45520] Tue, 05 October 2004 15:52 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18733
Registered: January 2001
Illuminati (33rd Degree)

If you are building tower two π speakers with 1/2" wood panels, cut the port hole 4.375" (4 3/8") diameter. There was an earlier discussion a while back about port sizes for the tower two π using alternate wood thickness, but we didn't discuss 1/2".

If you are building Studio two π speakers, just make sure that your port length is 1.875" (1 7/8") from entrace to exit. The front of the speaker face to the edge of the port inside should be 1.875". So if the baffle thickness is 0.5", then the duct material should extend 1.375" (1 3/8") into the cabinet interior.

Be sure to brace the cabinet very well, so that it is solid when you rap on it with your knuckles. You want it to sound like a rock, not a drum or a keg. You're probably alright on Studio two π speakers but the towers will definitely need braces. There are lots of good suggestions here in this forum, so you might do a search for "brace."


Bracing [message #45524 is a reply to message #45523] Wed, 06 October 2004 00:07 Go to previous message
tube_ee is currently offline  tube_ee
Messages: 5
Registered: May 2009
Esquire
I've got enough room in my cutting plan for one more piece the size of the top and bottom panels, so there's one "window" brace. If I go with the one brace every 18" that you've recommended elsewhere, I get one brace, about halfway between the woofer and the bottom of the speaker.

If I use one 15"x13" brace with 4"x3" cutouts, and run 1/2" x 1/2" vertical strips up each corner, with 2 horizontal strips per panel, I get a volume about 5 ft^3 less than what I calculate for an unbraced cabinet built with 5/8" stock. What effect will this difference have on the woofer alignment? Would this be sufficient bracing to compensate for the thinner walls?

For additional vibration-killing, what about gluing some asphalt roofing tiles to the insides of the panels? It shouldn't affect the volume much. Or you could use a marble plinth and thinner marble top, "sandwiching" the speaker between them, or...

The mind runs amok.

Tanks for all the help,
--Shannon



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