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52 Search Results Found |
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Forum: Pi Speakers «»
Posted on: Sat, 27 July 2002 00:57 «»
By: Wayne Parham
Re: altec gear in a pi box??
Check out the "Pi Alignment Theory" document. This shows what I do to align a cabinet - To pick a size and to tune it to specific frequency. It's based largely on the application of a Helmholtz resonator to provide specific frequency-sensitive loading fo...
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Forum: Pi Speakers «»
Posted on: Sun, 16 June 2002 17:14 «»
By: Jerry Parker
frequency vs. phase
Hi Wayne. Another question for ya. I was playing around with a signal generator on my computer, along with computer software called winisd, which you input theile small parameters and can find the response curves of different types of enclosures. Anyway...
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Forum: Pi Speakers «»
Posted on: Mon, 08 April 2002 20:26 «»
By: Wayne Parham
Mathematical models
Have you used Spice? That will allow you to model the electrical circuit perfectly, and the acoustic filter functions are simple enough that they can be modeled on it if you choose to do so. Coming at it from the other direction, you can use Thiele/Sma...
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Forum: Pi Speakers «»
Posted on: Tue, 01 January 2002 11:54 «»
By: Wayne Parham
Re: Enter PiAlign numbers in BoxPlot?
Click on "Box Parameters" and adjust the "Alpha" value to set cabinet volume until the bottom right corner shows "0.8 cubic feet." Adjust the "H" value until the Helmholtz resonant frequency shows 55Hz, which is also displayed in the bottom right corner. ...
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Forum: Pi Speakers «»
Posted on: Mon, 31 December 2001 14:39 «»
By: Wayne Parham
Determining mechanical reactance values for Spice models
You can find equivalent circuit values by backsolving the formulas Fr = 1/2π√LC and Q = √LC/R using the impedance graph and/or Thiele/Small parameters. For example, if you know that impedance at resonance is 50 ohms and the resonant frequen...
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Forum: Pi Speakers «»
Posted on: Sat, 29 September 2001 16:50 «»
By: Wayne Parham
Pi Alignments compared with B4, C4 and QB3, revisited
The Pi Alignment Theory describes a method for determining motor cabinet volume and tuning for any woofer. The cabinets it suggests are very similar to Davies' 1981 implementation of Thiele/Small analysis, so this is like asking whether there are some dri...
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Forum: Pi Speakers «»
Posted on: Fri, 28 September 2001 06:27 «»
By: Wayne Parham
PiAlign'ed at 2 cu ft tuned to 20Hz
You have a motor with these specs:Vas=5.33 cu ftFts=21HzQts=0.39So PiAlign equivalents are:Vad=5.33Frd=21HzQd=2.56PiAlign recommends a 2 cubic foot cabinet tuned to 20Hz using either a cylindrical 5" long, 1 5/8" diameter port or a rectangular 1" x 2" x 5"...
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Forum: Pi Speakers «»
Posted on: Wed, 29 August 2001 15:20 «»
By: Wayne Parham
Re: Newbie Question
Pi Alignments are for any type of speaker. They are not for a specific brand or type or characteristic. In fact, the formula describes an alignment that is very, very similar to Davies' 1982 optimal implementation of Thiele/Small analysis.As for usage, i...
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Forum: Pi Speakers «»
Posted on: Thu, 12 July 2001 18:04 «»
By: Wayne Parham
Extended bass response from small cabinets
Everybody wants deep bass from a cabinet no bigger than a lunchbox. Can we build a small box that makes deep bass? Well, yes. But can it also be efficient? The answer is no. Hoffman's Iron Law states you can have low cutoff, high efficiency or small s...
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Forum: Pi Speakers «»
Posted on: Mon, 25 June 2001 17:41 «»
By: Wayne Parham
Re: need help designing sub woofer cabinets
Thiele/Small (T/S) specs are electro-mechanical parameters. They're published for most modern woofers, so check with the manufacturer.By the way, I have a few very capable subwoofer designs. Check the PiSpeakers.com website and see if there's one there t...
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