Betsy's are on their way...

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I have some Wild Burrow Betsy full range drivers hopefully arriving in the next few days.

I love the look of these by FleaWatt

donkeykong.jpg

http://fleawatt.blogspot.co.uk/2012/12/fleawatt-wild-burro-betsy-donkey-kong.html

He lists the baffle as 3'8" x 3'8".

Does anyone have any other plans I could use as a starting point. I would like to try flat baffles first, not wings or H frames...

I have some Macassar Ebony and Birds Eye Maple veneer, and will use 18mm ply for the panel.

Any advise or tips much appreciated.

Thanks
 
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the larger the baffle, the deeper the bass.
I'd recommend 24" from speaker edge to baffle edge.

You can put them on hinges.
As long as I wrapped the back of the drip in foam, I could fold the wings back parallel or make a pseudo triangle box (not sealed).
My wife liked 6' tall, 12" wide, with swept back wings.
But mine rolled off at 200hz (15" deep wing and a higher mass corner (Fs/qts)).
My 1/2" birch ply "sang" (buzzed) on a James Taylor song, you may have to add some 2" x 2" x 2' to the back.


My 4 x 4" open backed box went deeper (2' wide x 2' tall x 2' deep).

The beauty of the open baffle is you can have a +3db to +6db in the bass that sounds lovely compared to a 12" wide sealed box with no baffle step.



and



You may want to notch a peak in the presence region.
The response is similar to the TB 1808, but with a bit more peak around 3khz.

For the money and the comments on the current paper cone, I believe they are excellent for the money, but I've not heard them.

Wild Burro Audio Labs - Fullrange Speakers - The Betsy & Betsy-K Drivers

Norman
 

GM

Member
Joined 2003
Well, until the baffle is an acoustical wave-length long at the desired low corner frequency it can't be too big. ;) Unfortunately, most folk's listening room is < ~70 Hz wide, so one has to factor in the room's impact on its response, ergo not a simple calculation, though a leading authority offers some insight how to get a starting point: Electro-acoustic models.

GM
 
Founder of XSA-Labs
Joined 2012
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The Betsy K works very well in a MLTL - see either the WIBAQ thread http://www.diyaudio.com/forums/full-range/226767-wibaq-tabaq-design-betsy-k-2.html or the AMLTL thread http://www.diyaudio.com/forums/full-range/231951-accidental-mltl-technique.html#post3408899.
The Betsy K has also been shown in sims to work very well in a Karslon K15 cabinet, see this thread: http://www.diyaudio.com/forums/full-range/237948-speaker-kicks-butt-large-spaces.html.
For smaller spaces and averge rooms, and placement near walls, use the MLTL design, for larger spaces and placement away from walls, the K15 works much better.
And if you like the combination of great deep bass extension of a ML-TQWT, but with the wide directivity of a Karlson-aperture, a 1.33X scale Karlsonator (40 in tall cabinet) is tough to beat. The frequency response, impedance, and cone displacement are below. This is with the speaker placed against a wall and measurement at 3 m away.
 

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Thanks!

Anyone tried or seen these used in an omni speaker?

I have the regular Betsy's and not the K model, if that changes cabinet choices.


Yeah, you could put them in an open baffle, or an open baffle. ;)

Actually, sometimes OB spec'd drivers will work well in a big fat open ended TL. Think 'boffle'. It could be worth a sim. AFA omni, I'd expect the highs might be a bit rolled off if you pointed this driver straight up, unless some sort of deflector or supplemental super tweeter was used.
 
Can anyone sim how large a flat baffle should be for the betsy?

This is so room, speaker and listening positioning dependent that any sim with any of the programs I've seen would be a crap-shoot at best unless one assumes either a very large baffle and impirically whittle it down/slope it to size or one that only factors in the driver's effective HF mass corner frequency [2*Fs/effective Qts] plus its near-field boundary conditions, which is normally the smallest practical one, ergo has the least usable [mid]bass output.

GM
 
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Sure, why not? :) Would this be sealed or open back/bottom? As an alternative, it looks like there's enough volume there that you could build it as two short fat TL/labyrinths and vent them out the bottom.


You might consider some sort of grill to keep from accidentally kicking the cones in, especially if people are going to sit on it. I'd use guitar speaker grill cloth myself.
 
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