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norman bates 25th June 2011 02:15 PM

tweakk, what size cap did you use with that horny ribbon ?


Taterworks 28th June 2011 01:10 PM

That transmission line cabinet doesn't look like it will be very effective as a resonator, because there is a possible path that a pressure wave could take through the enclosure that would almost be a straight line, due to the way the folding is done, and the fluid flow (airflow) will naturally try to follow the path of least resistance, so the line will behave like it is much shorter than what was probably modeled in Hornresp. The pieces that make up the TL labyrinth look more like reflectors than flow guides. I anticipate this design will need lots of stuffing to perform optimally.

e_fortier 14th April 2012 02:36 PM


Originally Posted by tweakk (

Beautiful enclosure, how do they sound.

I just bought a pair of Betsy K (they will be shipped next Monday) so I'm looking for some feedback on the sound if you can.

Thanks in advance,

Nanook 7th January 2013 07:02 PM

Betsy simple TL, really?
I think the posted graphic from Paul is more correctly a labyrinth. It reminds me of Lynn Olsen's Ariel in that it uses "offset" bracing or shelves to create it.

I would suggest considering the Demetri MLTQ from Planet10. I built a pair used with 8" FR drivers. It is very good, although a little large. In my case the FR still needs help from a decent tweeter. I have some Silverflute YAG 20-1/Dayton PT2C planar type tweeters that I'll add to them (simply mounted on top of the cabinets) or some Eminence 1-1/2" silk tweeters.

Strozzi 30th November 2013 11:37 PM

I am a novice when it comes to DIY speaker building, but i recently got a pair of Betsy-K drivers in an exchange deal.
I put them in an old Snell K/II enclosure (18 x 11 x 9 inch dimensions = 30 liters) just to mount them in something, and bypassed the tweeter and crossover which are still in the cabinet. I connected them to my 40W class A amp, and have let them play modest volume music for about 50 hours.
It sounds terrible, with an aggressive midrange which seem elevated compared to the rest of the freq range.
Do they need a notch filter or something to get an even freq.response? Is it not possible to use such an enclosure? Do they need longer burn-in?

I realize, having browsed through some of the forum articles about the BetsyK's, that they are mostly used in enormous horn-loaded enclosures, but that is out of the question for my part.

I do like the design of these BetsyK Simple TL by Paul / pjanda1 here in this thread, and have the means to build them. But i am still curious if they _could_ sound OK in the 30 liter Snell K II cabinets, as my original intention was to use these in my living room as TV-speakers.

But, if that is not possible, i will make the Simple TL build, and have them as an extra set of speakers in my music-listening-room.

Thank you for any help and insights,

Regards, Oyvind, Norway

tinitus 1st December 2013 12:06 AM

no bass I suppose ?

yeah, a simple Quaterwave might help to produce more 'volume'

anyone tried the old ACE-horn with omni mounted driver ?

GM 1st December 2013 07:15 AM

1 Attachment(s)
No 'hands on' experience with this driver, but plenty with its genre, so yes, a RLC network is one way to deal with its HF 'shout', though due to its rising on axis response, just toeing them in as required is often sufficient, but it may roll off the extreme HF too much if you still have youthful hearing.

Aiming the left one at the far right seating and right one at the far left is a good place to start.

Doing the 'full-range' driver $0.98 'tweak' can help too. This is inlaying a foam 'ring' or stuffing it with polyfil between the whizzer and diaphragm. Some folks have had some luck just using an elastic hair band [or two] or a 'scrunchie’: Scrunchie - Wikipedia, the free encyclopedia

I often knead the starch out of the whizzer and if I overdo it, then stiffen it back up some by applying shellac or similar while others coat them with Dammar or similar. Some folks just cut them off and add a [super] tweeter, so adapting the existing XO may be an option if the tweeters are still good.

These dimensions are outside [o.d.], but inside [i.d.] is what counts for determining box loading, so will have a somewhat smaller net volume [Vb], maybe as little as 19 L.

Regardless, since it’s sealed, using an HT’s 80 Hz XO should work fine once the speakers and LFE channel are level matched.

If you want to run them full range though, a much larger vented cab will be required.


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