FREE MONITOR PLAN: 12" Coaxial "Smithers Wedge" by Michael Smithers

Jeff Babcock

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Jan 11, 2011
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Ontario, Canada
jeffbabcock.org
Our SFN friend Michael Smithers provides this plan.

The Smithers Wedge is a low profile high quality 12" coaxial floor monitor design. Michael's design is based around the BMS 12CN680 which is a robust coaxial driver with good output and extended HF range. He also used a passive crossover design by Curtis List. Other drivers could be employed in this cabinet, with consideration for port tuning adjustments and with a different passive crossover (if passive functionality is desired).

Plans include CAD drawings and build photos, measurements of frequency response and impedance, etc. This cabinet is a relatively straightforward build for those who wish to make some sawdust, and will result in an excellent monitor that would be suitable for many monitoring applications.

Enjoy!

NOTE: For those who wish to build this monitor, please post your results and questions here.
 

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Ossian Ott

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Mar 21, 2015
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Re: FREE MONITOR PLAN: 12" Coaxial "Smithers Wedge" by Michael Smithers

Is this monitor more voiced towards live music/vocal applications rather than heavy Dj EDM material with lots of low-end information? I might build a pair, would it be preferable with 15" co-axial design?
 

Jack Arnott

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Jan 29, 2011
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Re: FREE MONITOR PLAN: 12" Coaxial "Smithers Wedge" by Michael Smithers

Is this monitor more voiced towards live music/vocal applications rather than heavy Dj EDM material with lots of low-end information? I might build a pair, would it be preferable with 15" co-axial design?
The BMS 12CN680 is definitely voiced towards live music/vocal, and high sensitivity. My opinion is that just dropping a 15" coaxial in this box will not be the solution. For instance, the BMS 15" coaxial (15CN680) will still have a 3" VC, and same basic design, to address sensitivity over LF extension. Even the tri-axials, with a 4" VC would need a sub to address the LF of EDM music, and that driver will not work in this box.

As an aside, it seems to me that there are physical constraints in the design of coaxial speakers, due to the magnetic fields. I notice that most coaxials (or professional ones, where it is not just one driver slapped on the back of another), have very similar VC sizes. I know a lot of physics goes into the interaction between the magnets, and this seems to be one of the outcomes.
 

Jack Arnott

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Jan 29, 2011
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Re: FREE MONITOR PLAN: 12" Coaxial "Smithers Wedge" by Michael Smithers

If by "it" you mean the monitor plans, they are linked in post #1.
Sorry, it did not seem to quote the whole post, and I did not proof that.
I was wondering where he found the link to the schematics for the crossover.
 

Jeff Babcock

Senior
Jan 11, 2011
972
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18
Ontario, Canada
jeffbabcock.org
Re: FREE MONITOR PLAN: 12" Coaxial "Smithers Wedge" by Michael Smithers

I'm not aware of the crossover plans for the BMS driver being published, they were a custom job by Curtis List, and quite a complex design at that. I believe he was selling them for about $150 each, though this was several years ago. Some alternative drivers do have stock crossovers that can be used, which is a much simpler arrangement for most. I believe Michael Smithers has since upgraded his into powered wedges without the need for a passive crossover.
 

Jason Webster

Freshman
Jan 28, 2018
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Hello All,

Would anyone happen to have the CNC files for the latest Smithers Wedge? Also has anyone used the B&C 12HCX76 in this box? If so, did it fit without any modifications? Does the port need to be altered? Lastly, how did it perform? Any feedback would be lovely as I am planning to build a few of these, thanks!
 
Sep 12, 2012
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I have been busy in the woodshop, took at crack at building a Smithers Wedgeoaded with B&C 12FCX76.

I have two questions:
  • Does anybody have any experience comparing the B&C crossovers versus biamping the cab.
  • Looking at LG IPD series for power. Would an IPD1200 be sufficient, or should I spring for the 2400? (My instinct says to bone up for the 2400)

Thanks Guys!
 

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