Bottlehead Forum

Other Gear => Speakers => Topic started by: Karl5150 on January 14, 2021, 04:47:58 AM

Title: New OB speakers
Post by: Karl5150 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. 

Title: Re: New OB speakers
Post by: Paul Birkeland on January 14, 2021, 06:56:07 AM

Those are rather substantial, even with the subs built in.

Title: Re: New OB speakers
Post by: Zimmer64 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

Title: Re: New OB speakers
Post by: Karl5150 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

Title: Re: New OB speakers
Post by: johnsonad on January 18, 2021, 05:35:49 AM

Those look nice Karl.  Sounds like a fun project!

Title: Re: New OB speakers
Post by: Larpy 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.

Title: Re: New OB speakers
Post by: johnsonad on January 18, 2021, 08:13:08 AM

Those look impressive Larry!

Title: Re: New OB speakers
Post by: Karl5150 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