ScottMoose BVR for Betsy K

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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!
 

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  • BVR Detail.png
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  • Betsy K BVR.png
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  • Betsy K BVR Sketchup.zip
    Betsy K BVR Sketchup.zip
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Last edited:
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!
 
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.
 

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  • BetsyK-BVR-Imped-3m.png
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  • BetsyK-BVR-Freq-Resp-3m.png
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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.
 

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  • IMG_0433 (Medium).JPG
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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.
 

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  • BetsyK-BVR-Freq-Resp-3m-Corner.png
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  • BetsyK-BVR-Freq-Resp-3m-Corner-Rear-Firing.png
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