Jeff Bagby's Revolution mini (with fabric Soft Dome tweeter)
Here is my build and measurements of the late Jeff Bagby's SB Acoustics Revolution Mini speaker.
For those uninitiated, the Revolution mini was designed by Jeff in late 2018. It follows the classic 1/4 cu. ft. mini monitor LS3/5A size. But this turned out better than expected, does everything from acapella to classical to jazz to rock. I’ve been in this game over 20 years, and it’s just phenomenal.
All the kit components were purchased in one convenient package from Meniscus Audio
(link removed- full disclosure: no affiliation)
The original uses a beryllium dome tweeter SB29SBAC.
I used the soft dome SB29SDAC tweeter, an official design option by Jeff.
However, I used the natural white MW13PNW-4 driver instead, and a slightly shorter cabinet (1") I maintained the original's 7L volume by reducing the depth, but keeping the width constant is very important. A measurement with this tweeter was not released publicly by Jeff, as far as I know, so I've wanted to document it here.
The original beryllium version is smoother in the upper mid and top octave, and the fabric dome version was simply an affordable stand in. Note that the wiggles under 500Hz are due to the effects of Jeff's room.
I never met Jeff, but corresponded with him from the days of Madisound BBS over 15 years.
Always kind, generous, and shared his knowledge. RIP.
Comparison of Jeff's own measurements with Beryllium tweeter (SB29BAC) and my build with soft dome tweeter, overlaid.
Polar maps:
Normalised polar maps:
Edit: Measurements in CTA2034A standard aka spinorama added.
Measurements method: quasi anechoic, Jeff Bagby's method- baffle diffraction compensated nearfield merged with farfield. Farfield taken with tweeter 2.4m from ground, on tweeter axis, 2.83V drive level. Microphone at tweeter axis 1m away, rotating turntable)
Here is my build and measurements of the late Jeff Bagby's SB Acoustics Revolution Mini speaker.
For those uninitiated, the Revolution mini was designed by Jeff in late 2018. It follows the classic 1/4 cu. ft. mini monitor LS3/5A size. But this turned out better than expected, does everything from acapella to classical to jazz to rock. I’ve been in this game over 20 years, and it’s just phenomenal.
All the kit components were purchased in one convenient package from Meniscus Audio
(link removed- full disclosure: no affiliation)
The original uses a beryllium dome tweeter SB29SBAC.
I used the soft dome SB29SDAC tweeter, an official design option by Jeff.
However, I used the natural white MW13PNW-4 driver instead, and a slightly shorter cabinet (1") I maintained the original's 7L volume by reducing the depth, but keeping the width constant is very important. A measurement with this tweeter was not released publicly by Jeff, as far as I know, so I've wanted to document it here.
The original beryllium version is smoother in the upper mid and top octave, and the fabric dome version was simply an affordable stand in. Note that the wiggles under 500Hz are due to the effects of Jeff's room.
I never met Jeff, but corresponded with him from the days of Madisound BBS over 15 years.
Always kind, generous, and shared his knowledge. RIP.
Comparison of Jeff's own measurements with Beryllium tweeter (SB29BAC) and my build with soft dome tweeter, overlaid.
Polar maps:
Normalised polar maps:
Edit: Measurements in CTA2034A standard aka spinorama added.
Measurements method: quasi anechoic, Jeff Bagby's method- baffle diffraction compensated nearfield merged with farfield. Farfield taken with tweeter 2.4m from ground, on tweeter axis, 2.83V drive level. Microphone at tweeter axis 1m away, rotating turntable)
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Well my previous speakers are
Jim Holtz Statement II
Music and Design NaO II
Like your own children, you don't have a best. But you want something the size of the LS3/5A or Jeff Bagby's own Continuum speaker, this is something special.
When I look at the measurements, sure, the first thing that sticks out is the top octave (10-20Khz) on-axis.
If that bothers you then build the one with the beryllium dome- it's a drop in replacement and doesn't have that failing/feature.
But the other thing that the visual measurements between 100Hz to 10Khz aren't telling me. Note this is unsmoothed- gating
7ms, so the curve is accurate down the where the line ends around 150Hz. In room there's bass to 50Hz, so it's all there for music. But why is the imaging is so spectacular?
Late night intimate listening has never been so good.
Jim Holtz Statement II
Music and Design NaO II
Like your own children, you don't have a best. But you want something the size of the LS3/5A or Jeff Bagby's own Continuum speaker, this is something special.
When I look at the measurements, sure, the first thing that sticks out is the top octave (10-20Khz) on-axis.
If that bothers you then build the one with the beryllium dome- it's a drop in replacement and doesn't have that failing/feature.
But the other thing that the visual measurements between 100Hz to 10Khz aren't telling me. Note this is unsmoothed- gating
7ms, so the curve is accurate down the where the line ends around 150Hz. In room there's bass to 50Hz, so it's all there for music. But why is the imaging is so spectacular?
Late night intimate listening has never been so good.
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I'm sorry if I am going to offended anyone, can I get the build plan and crossover schematic for the Jeff Bagby's Revolutions Mini and the Piccolo? If I need to purchase it, how much will it cost?
The SB Acoustics factory is in my country, so I think it will be wasteful to purchase the full kit from meniscus since the drivers will be exported then imported again to me + the shipping cost (shipping the full kit from meniscus will cost me $120+17,5% import tax) is too much for me. Thanks!
The SB Acoustics factory is in my country, so I think it will be wasteful to purchase the full kit from meniscus since the drivers will be exported then imported again to me + the shipping cost (shipping the full kit from meniscus will cost me $120+17,5% import tax) is too much for me. Thanks!
Its open source
?#?revolutionsbyjeffbagby? - Explore
I suggest donating to his family via paypal here for using his incredible good design
Donations - Meniscus Audio
?#?revolutionsbyjeffbagby? - Explore
I suggest donating to his family via paypal here for using his incredible good design
Donations - Meniscus Audio
2021 built U3.
52” tall, 60” wide, 26” deep. Over 500lbs.
https://usa.yamaha.com/products/musical_instruments/pianos/upright_pianos/u_series/u-series.html
Next time our spouses complain about our big speaker(s), say that you are thinking of buying a new drum kit!
my Revolution is tiny 12” x 8” x 8” and about 12lbs.
52” tall, 60” wide, 26” deep. Over 500lbs.
https://usa.yamaha.com/products/musical_instruments/pianos/upright_pianos/u_series/u-series.html
Next time our spouses complain about our big speaker(s), say that you are thinking of buying a new drum kit!
my Revolution is tiny 12” x 8” x 8” and about 12lbs.
Any thoughts on
Any merit swapping the woofer for the 5″ SATORI MW13TX-4 looks very juicy!
Seems theres no point going for the more expensive TW29BM over the SB29BAC? ...the only thing you get more sensitivity? But the teXtreme TW29TXN is cheaper... even the soft dome SB29SDAC doesn't give up much on specs. I wonder how different each of these tweeters sounds.
You must have gone 3/4" MDF then? I guess I should get out a pen an paper and work out 7 litres according to Jeffs 13" tall x 8" wide x by 7.5" deep basis
Any merit swapping the woofer for the 5″ SATORI MW13TX-4 looks very juicy!
Seems theres no point going for the more expensive TW29BM over the SB29BAC? ...the only thing you get more sensitivity? But the teXtreme TW29TXN is cheaper... even the soft dome SB29SDAC doesn't give up much on specs. I wonder how different each of these tweeters sounds.
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