Home » Sponsored » Pi Speakers » Wayne -- anyone? Dual ducted vents possible w/Pi Alignment?
Wayne -- anyone? Dual ducted vents possible w/Pi Alignment? [message #40995] Tue, 15 April 2003 12:51 Go to next message
Tinnitus is currently offline  Tinnitus
Messages: 5
Registered: May 2009
Esquire
If so, how does one calculate the lengths of the dual-ducts?

In standard Bass Reflex design one uses 1/2 Vb to calculate each duct.

I admit to being kicked-out of MENSA, so how do I proceed?

Note: I want to build "Konus Audio Essence" style enclosures (only ones with sufficient WAF) for my EV 12TRXB's (3.8 ft^3 as per PiAlign) and think dual down-firing ducts will provide optimimum 'balance' -- not to mention looking way-better than one little duct positioned assymetrically on the front. (Severe WAF deduction.) ; )


Hate to talk to myself -- but, use 1/2 Vas and run program twice [message #40996 is a reply to message #40995] Tue, 15 April 2003 13:08 Go to previous messageGo to next message
Tinnitus is currently offline  Tinnitus
Messages: 5
Registered: May 2009
Esquire
to determibe vents/ducts then add calculated 1/2 Vb's for total Vb?

Just musing -- and remembering how dumb I felt sitting on the lawn in front of the MENSA house... ; )

Mirror image speakers [message #40997 is a reply to message #40996] Tue, 15 April 2003 16:24 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18784
Registered: January 2001
Illuminati (33rd Degree)

You might want to grab a copy of BoxPlot, which will calculate dual ports.

once he has his Pi specs [message #41012 is a reply to message #40997] Wed, 16 April 2003 05:57 Go to previous messageGo to next message
Sam P. is currently offline  Sam P.
Messages: 307
Registered: May 2009
Grand Master
boxplot will do the trick. Sam
Re: once he has his Pi specs [message #41014 is a reply to message #41012] Wed, 16 April 2003 07:20 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18784
Registered: January 2001
Illuminati (33rd Degree)

Yep, that'll do it.

Dual Ducts for PiAligned 12TRXB Enclosures -- update... [message #41117 is a reply to message #40995] Wed, 23 April 2003 12:24 Go to previous messageGo to next message
Tinnitus is currently offline  Tinnitus
Messages: 5
Registered: May 2009
Esquire
Hello Wayne,

By using the Fb formula at JL Audio, and running it twice -- once for each 1/2 Vb, I came-up with 2 X 2.0 in. ID X 5.25 in. long ducts -- still tunes 3.8 Ft^3 to ~ 28 Hz, as called for in PiAlign for a single EV 12TRXB.

Q: Does doubling the Vent Area effect Damping Bandwidth? Real-World output?? Sound Quality???

Respectfully,

Stephen ; )


Vent area [message #41119 is a reply to message #41117] Wed, 23 April 2003 17:33 Go to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18784
Registered: January 2001
Illuminati (33rd Degree)

There are indeed a few things to consider here - One is the Helmholtz frequency and another is the Q of the resonator, which is determined by its ratio of reactance to resistance. There is also the issue of port airspeed, which matters if turbulance causes audible artifacts. So vent area is indeed one of the important factors to consider.

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