Home » Sponsored » Pi Speakers » Wayne, can I get the plans for the pi 7 18"?
Wayne, can I get the plans for the pi 7 18"? [message #53227] Wed, 18 February 2009 14:07 Go to next message
xcortes is currently offline  xcortes
Messages: 51
Registered: May 2009
Baron
thanks,

xavier

Re: Wayne, can I get the plans for the pi 7 18"? [message #53228 is a reply to message #53227] Wed, 18 February 2009 15:15 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18783
Registered: January 2001
Illuminati (33rd Degree)

Sorry, that one isn't available anymore. I may be able to dig up the plans on an older hard drive, but it isn't really necessary. If you want to build a seven π for use with a JBL 2241, 2242 or 2245, scale the bass bin cabinet up to being two feet wide and tune it to 30Hz. Scale all the dimensions that way, so it will be four feet tall, etc. The midhorn, tweeter and crossover are all the same. A more complete description can be found in the post called "seven Pi-18 cabinet dimensions."
Thanks. Another question [message #53229 is a reply to message #53228] Wed, 18 February 2009 15:54 Go to previous messageGo to next message
xcortes is currently offline  xcortes
Messages: 51
Registered: May 2009
Baron
When I simulate your midrange horn with hornresp I get response to somewhere between 400 and 600 hz depending on the driver. Yet you cross it over at 1.6khz. What am I overlooking?

Thanks again!

Re: Thanks. Another question [message #53230 is a reply to message #53229] Wed, 18 February 2009 17:23 Go to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18783
Registered: January 2001
Illuminati (33rd Degree)

I saw falling response in the simulations too but I kind of expect that in midhorns and tweeters. David McBean has done a wonderful job with Hornresp, and I've grown to trust it implicitly for modeling basshorns. It's less reliable on midhorns and tweeters, only because it uses a pistonic model. You have to measure a speaker to see what its behavior is like above the pistonic range.

Above a few hundred Hertz, the cone is no longer pistonic and areas of the cone are decoupled from the rest. This creates what is effectively a lower-mass section that operates semi-independently from the main body of the cone. At high frequency, this behavior is what makes a big part of the total response. They key is to use drivers with good damping, so these higher frequency modes are smooth. Voice coil cover shape and composition plays a major role in the response up high. Below you'll see the response curve of the midhorn with a Delta 10 driver; Other drivers will measure differently.

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