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275 Search Results Found |
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Forum: Pi Speakers «»
Posted on: Fri, 25 April 2008 12:21 «»
By: Wayne Parham
Port position
A Helmholtz resonator is not sensitive to port position, so in general, you can put the port wherever you want. However, in practice, there are two considerations:1. You do not want the port to rest in a standing wave node. If it does, then the loudspe...
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Forum: Pi Speakers «»
Posted on: Fri, 25 April 2008 11:36 «»
By: Wayne Parham
Helmholtz formula
Check out the Helmholtz formula below. You can tune to the same frequency using different port sizes. As port area is increased, port length also has to be increased to tune to the same frequency. When in doubt, measure impedance and look for the mini...
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Forum: Pi Speakers «»
Posted on: Sat, 15 March 2008 12:09 «»
By: Wayne Parham
Re: what can i do with a pair JBL 2206H woofer
The 2206 works well in boxes from 1ft3 to 3ft3, tuned from 50Hz to 60Hz. As you move towards the large end of this scale, you should also move towards a lower Helmholtz frequency. The 1ft3 box tuned to 60Hz has f3 of 70Hz. The 3ft3 box tuned to 50Hz is...
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Forum: Speaker «»
Posted on: Fri, 22 February 2008 11:53 «»
By: Wayne Parham
Re: Experiment, Insights pls?
My experience is either you have Helmholtz resonation or you have standing wave resonation, or sometimes a combination of the two. Quarter-wave pipes act like Helmholtz resonators in that they provide narrow bandwidth resonant phenomenon. They are diffe...
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Forum: Pi Speakers «»
Posted on: Fri, 25 January 2008 09:34 «»
By: Wayne Parham
Differences between subs
There are some basic differences between the two subs. The three π sub is a direct radiating reflex cabinet with Helmholtz frequency of 20Hz. The 12π hornsub is a push-pull folded horn with 1/4λ path length frequency of 30Hz.The LAB12 woofer is a good d...
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Forum: Pi Speakers «»
Posted on: Wed, 16 January 2008 21:11 «»
By: Wayne Parham
Re: Quarter wave ported box?
Yes it does matter where the port is placed, particularly in the situation you describe. You can definitely have both Helmholtz resonation and quarter-wave standing wave resonation, simultaneously.Martin King has a spreadsheet that is designed to model t...
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Forum: Pi Speakers «»
Posted on: Mon, 14 January 2008 13:31 «»
By: Wayne Parham
Re: Impedance rise in horns
I agree about checking into bandpass boxes. They might be smaller and could provide the SPL needed. On the other hand, if he doesn't need a large duct area then 5.5 feet could be folded into a pretty compact box. Could be six one way and half a dozen t...
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Forum: General «»
Posted on: Mon, 08 October 2007 01:07 «»
By: Wayne Parham
Re: Help with my car audio
Well, in layman's terms, the formula that predicts the frequency a box is tuned for assumes a straight port, not one that is bent or flared or made into a "T" shape. Those kinds of changes are straightforward, and a finite element analysis could surely b...
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Forum: Pi Speakers «»
Posted on: Mon, 24 September 2007 08:19 «»
By: Wayne Parham
Re: plan request & pi alignment Q
The internal dimensions of the cabinet have very little to do with response in most models, as they are bass reflex speakers. The tuning mechanism is Helmholtz resonation. An exception is the tower two π speaker, which is tall enough to develop stand...
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Forum: Pi Speakers «»
Posted on: Sat, 15 September 2007 02:59 «»
By: dB
Re: eminence speaker
Hi,I am not sure about accuracy, but here it is a site that looked pretty to me (in English and Metric units).
Helmholtz Resonance Calculator
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