diy synergy horn
Associated Show: Personal
Time: June 2016 - November 2017

The "Synergy Horn" is a patented concept designed by Tom Danley of Danley Sound Labs. The idea is to create a multi-way speaker who's components behave as a single point source of sound, creating a full range phase-coherent wave front that sounds like it originates somewhere just behind the throat of the horn. Two Synergy Horns spaced properly can create an incredibly life-like stereo image, with some comparing the sweet spot to "wearing headphones". Many people don't believe there isn't a third center speaker in the middle! Another benefit of the Synergy Horn concept is an incredibly smooth off-axis roll-off, helping to keep unwanted peaks and other response anomalies from exciting the room acoustics, allowing for precise deployments and reducing the need for room treatment.

With all that in mind, and a push from one of my mentors, I decided to try my hand at building a pair of such unique speakers. Having a background in set construction and carpentry, it seemed like an easy task! How wrong I was - cue an 18 month build with help from many incredible friends and mentors.

The original design was by Scott Hinson, who's partial walkthrough on DIY Audio provided the basis for my build. I ended up re-drawing the entire system in Sketch-Up and slightly modifying them to allow for either passive or active-crossover use via an 8-pole SpeakON NL8 rear connector. The entire process proved to be an incredibly rewarding experience, and while these speakers are purely for home-use, the concepts and lessons learned in their construction have proven applicable at every level of production.

Exploded CAD
Initial exploded CAD view of the cabinets. Final paint colors would be changed by the final revision.
Parts, Parts, Parts!
A layout of all electronic components of the speakers. Past the point of no return!
Inner Horn Sections
The horn sections were built from MDF due to it's smooth angle cuts and consistent density. Though it is fairly heavy and very susceptible to water damage, making it ill-suited for most professional speakers.
Assembled Cab
The outer cabinet was assembled using TigerPly 3/4" plywood due to its cost and relatively void-free assembly.
Painted Cab
The outer cabinet was painted with several layers of Duratex speaker paint and inlaid handles helped give the cabs a professional appearance. Countless layers of satin black spray paint sanded smooth and several more layer of satin red paint on the accent panel help to create an attractive and smooth finish for the inner horn. The harsh worklights highlight the imperfections in the satin finish, however under softer lighting indoors the finish looks much smoother.
Custom Compression Driver Mount
The original design utilized a 2x4 to wedge the compression driver in place. Wary of this solution, a mentor helped me design a steel plate to mount the driver to the throat of the horn. The driver screws in with flush-mount screws from the front, and is then screwed into the horn via 4 corner screws from the other side.
Drivers Mounted
This view shows all the speakers mounted to the horn mouth. Total driver count for a stereo pair included:
x8 8" Dayton woofers,
x8 4" Dayton mid-drivers
x2 1" PRV polyamide compression drivers
Passive Crossover
The 3-way passive crossover network was incredibly complex and took several hours to assemble and solder. Input and driver outputs are seen here flagged with tape.
Some Assembly Required
Wiring and final assembly taking place! Also shown is the PVC end-caps required to seal the mid-drivers.
Rear Panel
Rear panel showing NL8 connection, cross-over switch, and labels.
A finished shot of the cabinets in my apartment, located near my roommate's Magnepan Magneplanar speakers.
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Photo: Rear View of Synergy Horn, 2017

© 2021 Christian Ekren Design

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