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Old 11th September 2007, 06:25 AM   #11
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I stuck my head inside the earlier hegemans. The box was a square prism ~a foot & 2-3 high (baffle was at an angle with driver firing into a reflector). The bottom of the box was divided up into many square pipes of differing length.

A while back there was an aXp article (12/03) that described something similar but simplier applied to a subwoofer.

dave
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Old 11th September 2007, 06:39 AM   #12
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Quote:
Originally posted by planet10
I stuck my head inside the earlier hegemans. The box was a square prism ~a foot & 2-3 high (baffle was at an angle with driver firing into a reflector). The bottom of the box was divided up into many square pipes of differing length.

A while back there was an aXp article that described something simplier but similar.

dave
Thanks Dave. So as I begin to experiment, any suggestions, even WAG as to Sd, So? Or am I starting fron scratch? Sounds like I could have a plenum volume and build the box intenals similar to B&W matrix, but not open all the 'pipes' that form to the adjacent ones, and just block them at varying points. Should be relatively easy to make a test box. Final enclosure will be similar in size and appearance to the Duntech/Dunlavy's. Or at least that's the plan.
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Old 11th September 2007, 07:45 AM   #13
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I hesitate to suggest how big the pipes were because it was a long time ago and my memory of it is fuzzy. Something like an 8x8 or 12x12 arrary inside the ~12x12 box. The walls of the tubes were quite small, and i'm thinking aluminum or maybe painted cardboard... sorry, 30 years have only left faint details...

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Old 11th September 2007, 10:25 AM   #14
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Quote:
Originally posted by planet10
I hesitate to suggest how big the pipes were because it was a long time ago and my memory of it is fuzzy. Something like an 8x8 or 12x12 arrary inside the ~12x12 box. The walls of the tubes were quite small, and i'm thinking aluminum or maybe painted cardboard... sorry, 30 years have only left faint details...

dave
Thanks, that still gives me some ideas. Might make a straight rectangular test box, say 40x40 (driver here) and 180cm long with a simple longitudinal matrix and strart experimenting. Worth a sheet of scrap MDF to get it right. I guess an Sl=So TL type idea is as good a place to start as any.

Jus' thinkin' out loud.
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Old 11th September 2007, 04:13 PM   #15
sardonx is offline sardonx  Canada
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Interesting. Any idea on the details of the implementation?
I don't know the exact details. When i was working there Morrison had already begun making his cheaper non-transmission look-a likes with poly or paper woofers (as you can see on his site) and that's what we made for him.
On the real version, with the woofer out, there was a horizontal plate very close to the magnet which forced the sound to the outer walls where the transmission lines began.
The other thing I know is that tons of epoxy is used in the construction.
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Old 10th December 2008, 02:17 AM   #16
sergiof is offline sergiof  Portugal
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good night!

i'm a nweb in the forum, so please forgive me if my question is being silly...

i did some classical transmission line enclosures in the past, all of them "open ended". this time i would like to use a driver with an Fs at about 20Hz (coming to L26 from Seas) and do half wave ressonator like this one. that would give me a tube with almost 7meters lengh, which is impracticable.

i understand the concept of this one, but what i don't understand how to calculate the distance of the tube knowing it will get thinner and thinner... precisely like B&W Nautilus showned up!

can you please give me information about this? or where to search information to do so?

and considering that i would like to hear/feel the 20Hz with high fidelity, is this the ideal approach, or should i stick to the classical TLs?

thank you very much, and once again, please forgive me if i'm being to newb...
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Old 24th March 2010, 03:15 PM   #17
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Im wondering what would be the better end to mount the speaker? Mouth or throat?

How would do some push & pull system in a transmissionline?
I think it would be convient to get the max out of some work like lumbering enclosueres like this ones.
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Old 24th March 2010, 04:00 PM   #18
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Originally Posted by planet10 View Post
Morrison inherited that design from Stu Hegeman. The man was a genius. The enclosure can't really be called a TL thou as the lines aren't really long enuff.

dave
OT I know, but I had the pleasure of meeting Stu Hegeman in the early 80s. I also got to take home for audition a Hapi 1 preamp SN 0001.
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Old 24th March 2010, 04:16 PM   #19
Dr_EM is online now Dr_EM  United Kingdom
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A concept which has interested me greatly but I haven't managed to do much experimentation with. I should get some small cheap speakers (high fs) and plastic pipes and see how I can influence the impedence plot with different configurations, see how theory and practise come together

Seems as though a closed end TL would be excellent for a woofer assisted fullrange design or a system using an extended bandwidth midrange. I had even considered modifying the Dayton RS-52 with a Nautilus style tapering tube on it's rear, but the advantages are more applicable to passive crossover designs I feel.

Best of luck with your project, I look forward to reading your results

Last edited by Dr_EM; 24th March 2010 at 04:18 PM.
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Old 18th November 2010, 12:46 AM   #20
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fascinated by closed end TLs but don't fully understand how they work- do they have to be half wave, quarter wave etc

Last edited by Bill poster; 18th November 2010 at 01:12 AM.
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