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275 Search Results Found |
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Forum: Pi Speakers «»
Posted on: Fri, 14 November 2003 12:46 «»
By: Wayne Parham
4.75" diameter
A Helmholtz resonator of 5.5ft3 having a 4.75" diameter duct that's 1" long is tuned to 42.8Hz. The same size resonator with a 5" diameter duct that is 1" long is tuned to 41.5Hz. This isn't much of a difference, and so both vent sizes would probably wor...
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Forum: Pi Speakers «»
Posted on: Fri, 07 November 2003 11:20 «»
By: Wayne Parham
Re: Would you say . . .
Assuming resonance around 50Hz, wavelength at the Helmholtz and fo frequencies is around 20 feet, so distances that are less than about 5 feet are pretty insignificant, acoustically. At this scale, the distance between a room boundary and the woofer is ab...
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Forum: Pi Speakers «»
Posted on: Tue, 04 November 2003 21:39 «»
By: Wayne Parham
Port size for thicker baffles
Sounds like those are going to be absolutely great. Just a word about baffle thickness - Since the port length is set by panel thickness, the Helmholtz frequency is a function of the thickness of the wood. I recommend changing the port diameter so that t...
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Forum: Pi Speakers «»
Posted on: Sun, 28 September 2003 15:42 «»
By: AstroSonic
Re: Looking for suggestions - EBS Alignment?
Wayne provided a 'graphic' illustration of what an EBS alignment is. I would only add that tuning still lower will produce a saddle and peak, tuning a little higher (to maximally flat) will produce a 'flat' response from the speaker, and tuning still high...
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Forum: Pi Speakers «»
Posted on: Mon, 15 September 2003 08:14 «»
By: Adrian Mack
Re: Pneumatic loading
Cool, makes sense.One last thing, the sealed box resonantes at Fo, so thats where control is the least. On a vented box, is control the least at Fb because thats where it resonants? Or is it Fo and Fb because theres a Helmholtz resonator and the shifted me...
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Forum: Pi Speakers «»
Posted on: Mon, 15 September 2003 01:40 «»
By: Adrian Mack
Ah, I figured most of it out
Hi Wayne,I just re-read your Electrical, mechanical and pneumatic properties post. The sealed box modifies the speakers mechanical properties and it raises Fs and changes its Qts. It does that by changing its spring stiffness and resistance because of the ...
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Forum: Pi Speakers «»
Posted on: Mon, 15 September 2003 01:22 «»
By: Adrian Mack
Re: Cool.
Hey Wayne,So it seems that the sealed box shifts resonance upward. The resonant frequency of the box/woofer system is Fo. But does this shift Fs upward too..... ? I'd assume that any ringing will occur at Fo too, where the electrical impedance peak is. If ...
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Forum: Pi Speakers «»
Posted on: Sun, 14 September 2003 02:24 «»
By: Wayne Parham
Re: PiAlign port
What I am referring to as waveguide behaviour is the same thing that you are calling self-resonance or "pipe-organ" resonance. It is caused by standing waves within the duct, and is different from Helmholtz resonation.It is entirely reasonable to explore ...
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Forum: Pi Speakers «»
Posted on: Sun, 14 September 2003 01:37 «»
By: Wayne Parham
Re: Cool.
In an air-suspenson speaker, there is really only one resonant frequency, and it is that of the woofer/box system. You can think of it as being just the woofer, with the box stiffening it and shifting the resonant frequency higher. That's basically what ...
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Forum: Pi Speakers «»
Posted on: Sun, 14 September 2003 00:45 «»
By: Adrian Mack
Re: Cool.
Hey Wayne,Great. LAB12 is pretty cool ey, except it uses Kapton instead of aluminium or black aluminium voice coil former, kapton is supposed to heat quicker and handle less power which isn't good. I think they could have used it, apparantly its not much c...
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