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November 26, 2021, 03:33:39 PM

Author Topic: New OB speakers  (Read 945 times)

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Offline Karl5150

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New OB speakers
« on: January 14, 2021, 04:47:58 AM »
One of my Covid projects was a pair of Betsy OBs built to the simple Wild Burro site instructions out of 0.75" Plyboo. They sounded good with a couple of subs for the lowest registers. But they were huge. I did some readjusting, adding a pair of 15" woofers for the bottom end and losing the separate subs. They are still big, but the form is more acceptable to the other half. They give up some finesse to my Tekton 4.5 OBs, but they rock a bit more, a good trade...for now. 
Karl
Downstairs: Planar3>Eros>Stereomour II>diy OB Betsy+
Upstairs: DIY RP1>Reduction / CD5004>Seductor/SEX 3.1.1>FH3/DT770 pro/HE-4xx
Office: Schiit Modi Uber 2 / Sirius Tuner>SEX 2.1.1>µFonken FF85WK with diy subs
Garage: CA x12 streamer>Quicksand>Minimus 77

Offline Paul Birkeland

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Re: New OB speakers
« Reply #1 on: January 14, 2021, 06:56:07 AM »
Those are rather substantial, even with the subs built in.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Zimmer64

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Re: New OB speakers
« Reply #2 on: January 16, 2021, 09:35:31 AM »
Nice! I am sure they sound lovely.

I did build OBs with Betsies 5 years ago and they are still in service. I went 3-way, tri-amping and active XO.

https://zimmer64.wordpress.com/2015/11/08/bg-neo3-betsy-eminence-alpha-15-a-mk-iii/

Michael
« Last Edit: January 16, 2021, 09:37:15 AM by Zimmer64 »
Nelson Pass F5 Turbo V2, Quickie (mod), S.E.X. 2.1, Tubes4hifi SP14, Dynaco VTA ST 70, Tubelab SSE, Vroemen Diva Superiore ER4, Jordan JX92S VTL, 47 labs 0647 CD, Aqvox DAC, Rowen Absolute pre / psu / power amps, BG Neo3 / Betsy / Eminence A15 open baffles

Offline Karl5150

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Re: New OB speakers
« Reply #3 on: January 18, 2021, 04:40:38 AM »
Thank you, they do sound very good to my ears. Nice work on the 3-ways Michael, that is a substantial baffle.
The original plan was to eventually include a small version of Mr. Pass' SLOB subs, 1 pair of 8s per side.
Now the next steps will be to narrow the bases by about 5-6 inches (there doesn't seem to be any adverse effect from having the wings being angled back more), add a 6 x 12 inch horizontal shelf to the back of the baffle, between the drivers, and make a couple of mock-up wings that are 3-4 inches shorter to evaluate any loss or change in bass output. (I don't want to trim the bamboo until I am confidant that I won't regret it.)
Karl
Karl
Downstairs: Planar3>Eros>Stereomour II>diy OB Betsy+
Upstairs: DIY RP1>Reduction / CD5004>Seductor/SEX 3.1.1>FH3/DT770 pro/HE-4xx
Office: Schiit Modi Uber 2 / Sirius Tuner>SEX 2.1.1>µFonken FF85WK with diy subs
Garage: CA x12 streamer>Quicksand>Minimus 77

Offline johnsonad

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Re: New OB speakers
« Reply #4 on: January 18, 2021, 05:35:49 AM »
Those look nice Karl.  Sounds like a fun project!
Aaron Johnson

Offline Larpy

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Re: New OB speakers
« Reply #5 on: January 18, 2021, 05:48:47 AM »
My first pair of OB speakers was a Betsy built by Randy of Caintuck Audio.  Being an inveterate DIYer, it wasn't long before I made by own using the Lii Audio F15 driver.  Then I built a couple of GR Research OB servo subs to get deeper bass.  Eventually I experimented with tweeters to fill out the top two octaves (not that I can hear much of the top octave anymore).

It all happened by trial and error.  Attached is what I ended up with.

Looks a bit '50s scifi-ish, which I like.  The subs are driven by their own plate amps.  The main speakers and tweeters are driven by my Kaiju.  Sounds terrific.
« Last Edit: January 18, 2021, 05:51:17 AM by Larpy »
Larry

Offline johnsonad

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Re: New OB speakers
« Reply #6 on: January 18, 2021, 08:13:08 AM »
Those look impressive Larry!
Aaron Johnson

Offline Karl5150

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Re: New OB speakers
« Reply #7 on: January 20, 2021, 03:09:54 AM »
I read good things about those Lii drivers on DiyAudio. That is some substantial plywood Larry, and I'm betting those are not small speakers.
Karl
Karl
Downstairs: Planar3>Eros>Stereomour II>diy OB Betsy+
Upstairs: DIY RP1>Reduction / CD5004>Seductor/SEX 3.1.1>FH3/DT770 pro/HE-4xx
Office: Schiit Modi Uber 2 / Sirius Tuner>SEX 2.1.1>µFonken FF85WK with diy subs
Garage: CA x12 streamer>Quicksand>Minimus 77