ScottMoose BVR for Betsy K

[thejessman]

I used some Betsy K drivers for a pair of speakers I built for a friend and now I've got to have some for myself. I'm interested in the double mouth BVR ScottMoose designed for them, but I'm not 100% sure of the dimensions, especially for the ports. What I got came from this post: http://www.diyaudio.com/forums/wild-burro-audio/156107-enclosure-designs-burro-speakers.html#post2527582

And here are the specs ScottMoose sent me for a double mouth BVR:

Chamber internal HxWxD = 37in x 10.5in x 12.25in. Driver mounted centrally; suggest a couple of window braces at least. Back, one side & either the top or base of the chamber (making sure you don't block the throat) lined with 1in acoustic fiberglass or similar. Throats are 1in deep & 0.75in long. Each horn is 14.5in tall at the mouth; an angled strike-plate runs from the front of the box to 1.5in down / up (depending on which horn we're talking about) from the throats.

Here are some shots showing the dimensions in Sketchup and I attached the Sketchup model . If anyone (like ScottMoose ) could look this over and let me know if I got it right I'd really appreciate it.

Thanks in advance!

 

[thejessman]

Something happened to my original post, weird, anyway:

I used some Betsy K drivers for a pair of speakers I built for a friend and now I've got to have some for myself. I'm interested in the double mouth BVR ScottMoose designed for them, but I'm not 100% sure of the dimensions, especially for the ports. What I got came from this post: http://www.diyaudio.com/forums/wild-burro-audio/156107-enclosure-designs-burro-speakers.html#post2527582

And here are the specs ScottMoose sent me for a double mouth BVR:

Chamber internal HxWxD = 37in x 10.5in x 12.25in. Driver mounted centrally; suggest a couple of window braces at least. Back, one side & either the top or base of the chamber (making sure you don't block the throat) lined with 1in acoustic fiberglass or similar. Throats are 1in deep & 0.75in long. Each horn is 14.5in tall at the mouth; an angled strike-plate runs from the front of the box to 1.5in down / up (depending on which horn we're talking about) from the throats.

Here are some shots showing the dimensions in Sketchup and I attached the Sketchup model . If anyone (like ScottMoose ) could look this over and let me know if I got it right I'd really appreciate it.

Thanks in advance!

 

[thejessman]

Anyone?

 

[xrk971]

Based on written description, it sounds like you have the drawing right. Of course, Scottmoose should be the final word. This would be a pretty straightforward speaker to model in Akabak. Very big speaker.

 

[thejessman]

Thanks, I need to learn how to use Akabak one of these days, I feel like I have a good handle of Hornresp, just haven't taken the leap to figure out Akabak yet.

 

[Bjohannesen]

Just an idea, TABAQ GIANT

 

[freddi]

BetsyK will work pretty well in a Karlson 12" coupler. It will play loud enough to burn out - but not from over excursion..

 

[xrk971]

My sims show that Betsy K will sound good in an original K15 too.
This is 3 meters away with 1 watt input.

Details on simulation here: http://www.diyaudio.com/forums/full-range/213594-karlson-10.html#post3528706

 

[xrk971]

Just an idea, TABAQ GIANT

+1. The WIBAQ is easy to build and the builder says it works very well with bass down to 30 Hz.

 

[xrk971]

Sim of Betsy BVR

Here is an AkAbak model of the BVR as drawn above. This is for the speaker 60 in away from a back wall and measurements at 3 m away at speaker centerline with 1 watt input.

The simulations show that the bass peaks at about 80 Hz and softly rolls off below that. If you are looking for deep bass, I am not sure if this will work. Also there appears to be a dip at 140 Hz and 240 Hz and sharp spike at 380 Hz. I may have done something wrong with the model, but this is a pretty straight forward design with only 11 nodes and two horns.

 

[thejessman]

Thanks for the input folks. I had considered the WIBAQ before and may have to give it a second thought. If I could get decent output down to close to 30 Hz that would be great. My main motivations for building the BVR enclosure was to get a little better lower frequency performance than Wild Burro's Quasi TQWT design, and the BVR looked like a more rewarding woodworking project (I'm a builder at heart, and have pretty much have all the skills/tools to build just about anything I want out of wood).

The WIBAQ looks like it would satisfy my first requirement pretty well, the only reason I have hesistant to go with it is its not very exciting from a construction perspective and its 4" deeper than the BVR design and that will decrease the all-important WAF. The BVR has exactly the same footprint as the Quasi TQWT design does, its just taller. Here is a picture of the TQWT cabinets I built for a friend.

 

[Scottmoose]

I'm away until Friday, & can't see pictures due to the exigencies of what I'm having to use to access the 'net until then, but I'll take a proper look when I get back.

 

[thejessman]

I'm away until Friday, & can't see pictures due to the exigencies of what I'm having to use to access the 'net until then, but I'll take a proper look when I get back.

Awesome. Thank you very much!

 

[xrk971]

Sims of BVR with corner loading, mounted 24 in from either wall and pointing 45 deg out. Next plot is with rear firing ports. It improved the bass extension and gain significantly.

 

[derwhalfisch]

I love my BetsyK BVR's. I love them, but I currently have them swapped out. I'll get them back into the system and re-measure the dimensions to check against your diagrams. I'll get a bass sweep from my preferred seat.

Gimme a couple of days.

--dwf

 

[thejessman]

I love my BetsyK BVR's. I love them, but I currently have them swapped out. I'll get them back into the system and re-measure the dimensions to check against your diagrams. I'll get a bass sweep from my preferred seat.

Gimme a couple of days.

--dwf

Thanks dwf, your input is greatly appreciated!

 

[thejessman]

For those interested I've updated the SketchUp model with a few minor tweaks.

 

[thejessman]

Just a heads up to Scottmoose to see if he has had a chance to take a look at this yet. Thanks!!

 

[sideways]

Anyway a pic can be posted for those of us who don't have SketchUp??

Thanks!!

 

[thejessman]

Anyway a pic can be posted for those of us who don't have SketchUp??

Thanks!!

There are a couple in my original post, if for some reason you can't see them or you need more just let me know and I'll be happy to put more up.