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Old 30th September 2012, 10:10 AM   #11
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Which design in particular?
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Old 30th September 2012, 06:21 PM   #12
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For example The Frugel-Horn
Could you tel me something more about this project ?
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Old 30th September 2012, 06:29 PM   #13
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Frugel-Horn Mk3

IMHO, the FH3 was an inspired flash of genius on Scott's part.

dave
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Old 30th September 2012, 08:32 PM   #14
Bigun is offline Bigun  Canada
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completely off topic, but Scott, if you fancy a Canadian style moose for your avatar I think you should get a nice shot from the Fall when their antlers are in full display.

I'm a big fan of this animal, and have experienced one arising out of a lake and walking through my camp site early one morning in the middle of the Canadian wilderness.
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Old 30th September 2012, 08:38 PM   #15
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Good - thank you
"genius" - sounds good
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Old 30th September 2012, 09:02 PM   #16
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Quote:
Originally Posted by Bigun View Post
completely off topic, but Scott, if you fancy a Canadian style moose for your avatar I think you should get a nice shot from the Fall when their antlers are in full display.

I'm a big fan of this animal, and have experienced one arising out of a lake and walking through my camp site early one morning in the middle of the Canadian wilderness.
A fine moose (a creature I have a great liking for). It's the nose that does it for me. As it happens, my avatar is actually of a yak, which I also happen to like, particularly after reading Donald Bisset's various stories feature said creature.

Last edited by Scottmoose; 30th September 2012 at 09:04 PM.
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Old 1st October 2012, 05:48 PM   #17
chrisb is offline chrisb  Canada
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Quote:
Originally Posted by Scottmoose View Post
A fine moose (a creature I have a great liking for). It's the nose that does it for me. As it happens, my avatar is actually of a yak, which I also happen to like, particularly after reading Donald Bisset's various stories feature said creature.


BBC NEWS | Science/Nature | Moose back on the loose


with or without an impressive rack, a full grown moose is not to be trifled with, as any game hunter or truck driver in the interior of BC will tell you

I don't think anyone has successfully tried to domestic the species

Scott's avatar is

Datei:Yak at third lake in Gokyo.jpg ? Wikipedia

Click the image to open in full size.

I'm not sure if he's been up close and personal with one, but for some reason I suspect it'd be like Hans said about the Tauntaun sleeping bag


survive the solar orbit celebration mostly intact, Mr L?
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Old 1st October 2012, 05:59 PM   #18
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Originally Posted by Scottmoose View Post
You don't get anything for nothing in this life. All chambered back-horns are essentially more or less extreme variations on the bass reflex theme, and like all back loads, are only useful over a relatively narrow BW.

The short version is that Martin's added an internal Helmholtz resonator to his back-horn, tuned to the design / target Fh to increase the acoustic low-pass slope.
if possible could you give me a quick brief on what exactly a helmholtz resonator does and why it would be included in a design?

thanks
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Old 1st October 2012, 06:33 PM   #19
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A Helmholtz resonantor is a cavity that resonates at a specific frequency -well, narrow BW of frequencies to be exact, since it doesn't just appear at one point & instantly vanish to either side of it. They're often used in loudspeaker design to reinforce the low-range: that's what a bass-reflex enclosure is. However, they can also be used for the opposite effect: to trap a specific frequency or narrow BW of frequencies. That's how some of the big bass-traps you see work. They're just boxes with a port, tuned to a specific problem frequency.

What we have here is an internal version of this. Martin has used it tuned to, or slightly above, the upper corner frequency of the horn, to provide a steeper acoustic low-pass slope than it would otherwise have -it's not a new idea, but it isn't used all that often either. It's a useful card to have up your sleeve, but there are a couple of things to keep in mind: while it will increase the rate of the initial roll-off, the resulting slope will be akin to a cauer (eliptical) filter since the resonator / absorber is by nature a narrow band device. Therefore, you need to ensure you have a reasonably fast acoustic low-pass initially to ensure the secondary peak that will result above the tuning frequency of the absorber is at a sufficiently low level not to be noticable. If you've done that, as Martin evidently has, you're in business.

Last edited by Scottmoose; 1st October 2012 at 06:50 PM.
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Old 1st October 2012, 09:55 PM   #20
chrisb is offline chrisb  Canada
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IINM, Lowther and likely others have used the HR approach, but perhaps not as thoroughly "new" mathed out as any of Martin's projects would be.
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