Friday, December 18, 2015

New Folded Corner Midrange Horn - Twin Back Chambers

Back chambers for the twin drivers in the New Folded Corner Midrange Horn should help to improve overall performance of the horn.  PVC pipe and 1/8" Masonite form the mounting flange and walls of the back chambers while a disc of mahogany plywood provides a cover.

First, it is necessary to plug all of the holes in the throat flange:


New Folded Midrange Horn - Throat Flange
New Folded Midrange Horn - Throat Flange
 A new flange is cut out of 1/8" Masonite.  Four flat-head wood screws fasten driver, flange, and pvc pipe together.  The assembly is pictured below set upside down on the throat flange.  It is necessary to chamfer the edge of the flange to allow clearance for the driver surround.


New Folded Midrange Horn - Flange-Driver-PVC Pipe Assembly
New Folded Midrange Horn - Flange-Driver-PVC Pipe Assembly
 The assembly is positioned over the throat flange for drilling and countersinking.


New Folded Midrange Horn - In Position For Drilling and Countersinking
New Folded Midrange Horn - In Position For Drilling and Countersinking
 Two 1/16" holes are drilled through the PVC for the driver leads.

New Folded Midrange Horn - Holes for Leads
New Folded Midrange Horn - Holes for Leads
Wires are fed through the holes and ends stripped.

New Folded Midrange Horn - Lead Ends Stripped
New Folded Midrange Horn - Lead Ends Stripped
 The back chamber assembly is now in position and fastened.

New Folded Midrange Horn - Back Chamber Assembly Fastened
New Folded Midrange Horn - Back Chamber Assembly Fastened
 The mahogany plywood disc is provided with black electrical tape as a gasket for a reasonably tight fit in the PVC pipe.

New Folded Midrange Horn - Back Chamber Cover
New Folded Midrange Horn - Back Chamber Cover
The twin driver and back chamber are already installed.  Here is the setup to test impedance as a function of frequency.


It will be interesting to see how the measured impedance vs frequency plot compares with the one predicted in Hornresp.

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