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Old 10th November 2011, 11:48 PM   #931
zacster is offline zacster  United States
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Location: NYC
Thanks. When I did a search the other day, half the results pointed back to my own searches from years past!

And maybe YOU could measure them. I wouldn't have a clue where to start.
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Old 11th November 2011, 12:33 AM   #932
GM is offline GM  United States
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Location: Chamblee, Ga.
I could, but I don't have them. Do a Google search, there's loads of posts and even whole threads and websites devoted to the subject.

Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
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Old 11th November 2011, 02:34 AM   #933
zacster is offline zacster  United States
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At this point I'm just going to build them. They're going to end up as speakers for my teenage kids. They're not picky. I can't even convince them to get decent headphones/earbuds. They like the cheap ones even when I'm paying.
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Old 11th November 2011, 07:38 PM   #934
tmblack is offline tmblack  United Kingdom
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I'm a total newbie when it comes to the metronome.
What's a ML-QQWT or a Mass Loaded Quadratic Quarter-Wave Tube mean?
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Old 11th November 2011, 08:53 PM   #935
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TQWT = TQWP = Tapered Quarter Wave Tube/Pipe

These are a pipe/transmission line open at one end, where the closed end is smaller then the open end.

Also called a Voigt Pipe.

These suffer from a lot of ripple and can be dramatically improved by mass-loading them (restricting the terminus/opening). This is often implemented with a small pipe as in a bass reflex (which confuses a lot of people)


When the 1st ideas of this kind of load in the form of a cone (which Steve took to a pyramid) it was completely missed that with a taper in 2 axis, the actual "shape" of the volume is quadratic and not linear. They are closely related and as tolerent as they are a Met can usually be simmed as an ML-V.

Click the image to open in full size.

community sites,, ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
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Old 14th November 2011, 04:43 PM   #936
tmblack is offline tmblack  United Kingdom
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There's a Mathcad simulation of horns and ML-QQWT out there but I can't find it.
Anyone know what I'm talking about?
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Old 15th November 2011, 04:44 AM   #937
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Originally Posted by tmblack View Post
There's a Mathcad simulation of horns and ML-QQWT out there but I can't find it.Anyone know what I'm talking about?
Hi there: Google-up: the Martin J King site. ...regards, Michael
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Old 16th November 2011, 04:25 PM   #938
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Have any of these been built with Mark Audio drivers? Specifically the Alpair12?

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Old 16th November 2011, 05:36 PM   #939
sherpa is offline sherpa  United States
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So they are finally finished. I broke the drivers in mounted in an open baffle for 200+ hours. They are built using 3/4 birch plywood. The top 4 feet of the insides are lined with 4mm laminate flooring felt. First impressions, The image is incredible and detailed. Right away i was hearing parts of the music that i could not hear with my Zigmahornets. These things revealed the limitations in my SE EL-84 amp and the 6EM7 amps i have. When i run my DIYTube ST-35 the sound is clear and clean. I have had several people listen to them so far and have come up with some limitations. The midrange is almost too forward and the bass is lacking. I know they will never be a rock and roll kick you in the chest style speaker but the bottom end is just not balanced with the rest of the frequency. I believe i have three options to tune these things in, Stuffing, Play with the port size and length, or a BSC filter. Where should i start? What changes can i expect from each method? I have considered that my amp is lacking the bottom end reproduction. running with a friends old heathkit solid state 120w amp there was an improvement in the bottom end. If i can sell some of the equipment i have it will fund the building of the tubelab SE with some CSXE 25W Edcor outputs. I hope these pictures came through.
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Old 17th November 2011, 02:13 PM   #940
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Hi Sherpa,

The first thing that concerns me is that you appear to have lined three sides. When I did my first build (FE108eSigma) I lined all sides of the interior. What a disaster! I had to cut into the port baffles on the bottom to get in so I could remove the lining from the front and sides. On all three of my Met builds I have lined only the back, from top to bottom.

The FE108eSigma Mets have a BSC of 1 mH and 4.5 ohms. The F120A didn't need any BSC. The Fe167e have a BSC of 0.7 mH and 2.2 ohms. Not sure what the FF125wk might need, but it sounds like they need some.

Cheers, Jim
A day without music is like a day without food.
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