Designer: Bill S. (4thtry)

Project Time: 20+ Hours
Project Complexity: Advanced
Project Cost: $500-$1000

Project Description
This is a small floor standing two way using the new Dayton Audio Esoteric ES180Ti-8 woofer and ES25Nd-4 tweeter. The woofer is loaded into a 59” long tapered transmission line with a 16:1 taper ratio and a 31Hz tuning frequency. The acoustic centers of the tweeter and woofer are aligned at the crossover frequency using a 10 degree sloped front baffle.

Design Goals
I prefer small, stand mounted speakers with small baffle surface areas because I think they image better than larger speakers with wider baffles. At the same time, I like the extended low frequency response made possible by larger cabinets. My solution to this dilemma was to create a larger cabinet with an unusual, “jack rabbit” type shape. By sloping the top and bottom sections away from the listener, I was able to effectively reduce the baffle area to that of a small bookshelf speaker on a stand.

PETT forum member “dcibel” commented that my speaker looked like it was going to hop away. I replied that, hopefully, it will not hop away before I have a chance to build & measure it!

Driver Selection
For my design, I selected the new Dayton ES180Ti-8 (295-397) and ES25Nd-4 (275-151) drivers. The woofer uses dual copper shorting rings, a large 3” voice coil on titanium former, and a specially woven glass fiber cone. The tweeter has a pinned center dome, a powerful neodymium magnet, and a very low free air resonance of approximately 600Hz. This allowed me to push the crossover down to a very low 1.65kHz without getting too close to the tweeter’s resonance.

Enclosure Design
I used a CAD software package to layout the cabinet shape, creating a profile from a tapered transmission line that was 78 square inches at the beginning area and 5 square inches at the ending area (terminus). I then broke the tapered line into 4 sections and rotated them into the final profile. I sent my tentative sketches to Paul Kittinger and he manipulated and
manually re-drafted them into a final shape that produced the best overall low frequency response.

Enclosure Assembly
Total project time is best estimated at 200+ hours; not 20+ hours as indicated above! Because of all the custom cutting, alignment fixtures, template creation, etc., it took me over 2
months alone, working roughly 4 hrs per day, just to create the basic shape of the raw MDF cabinets! Assembly required the creation of 14 custom fixtures and templates! It was a lot of work, but the final cabinets, when painted, have a very arresting, dynamic look to them, making all the time spent well worth the effort. Time consuming, yes; totally beyond reason, no!

I created a full-scale paper template of the profile from Paul’s drawings and used it to cut out the side panels with a circular saw. Then I aligned the side profile panels with a custom
alignment fixture and temporary separation boxes. Front, top, and back panels were then each custom cut using my table saw and compound sliding miter saw.

I glued everything together with clamps & yellow carpenter’s glue. No wood screws were used. I cut 1/16” wide by 1/16” deep shadow lines along all glue joints with my router using a 1/16” straight bit set to a depth of 1/16”. I used custom straight edges, stop blocks, and alignment gauges for each cut.

The finished cabinets were spray painted with 2 coats of oil based primer and then 3 coats of oil based high gloss enamel. I shot the paint at 70psi using a conventional spray gun. As a
final step, I hand painted the shadow lines flat black to create accent lines along the cabinet profile.

Crossover Design
I created the crossover using OmniMic, WT3, and Bill Waslo’s new Xsim crossover modeling program. I also had assistance in the form of several excellent tips and suggestions from PETT forum members Ben Shaffer and John Hollander.

I chose a low crossover frequency of 1.65kHz to help suppress woofer break-up modes, reduce “beaming,” and improve stereo imaging. Also, the tweeter’s low Fs and high power handling ability helped to keep distortion in check at this low crossover point. Slopes are 12dB/octave electrical. Phase tracking throughout the crossover region looks good with a deep, sharp reverse polarity null.

To contour the tweeter’s frequency response, I used Ben’s recommended tweeter zobel together with a separate HF response shaping inductor across padding resistor R2. For the woofer, I knocked down the 3.5kHz breakup mode with a tank filter. And I further re-shaped a bulge in the 1khz region with a zobel network. The final filter components chosen provide roughly 3-5dB of baffle step compensation (BSC).

I measured both the on and off-axis frequency response of the final crossover with the speakers mounted in the final Linehopper cabinets. I also measured both on and off-axis response with the drivers and crossover mounted in a much smaller bookshelf sized cabinet using the same 8.125×13” baffle board dimensions. Aside from the lowest frequencies, the curves were almost identical. Not only did the final system measure just like a small speaker on a stand, it also tended to sound that way, projecting a very convincing stereo image. Finally, the cone materials used in these new drivers seem to produce a very clean, crisp sound quality that, to my ears, remind me of a much higher priced planar type system.

Tips & Tricks


275-151 Dayton Audio ES25Nd-4 Ring Done Tweeter 2
295-397 Dayton Audio ES180Ti-8 7” Woofer 2
260-285 Square Speaker Terminal 2
260-317 Acousta Stuf 1 lb bag 2
005-4.5 Mills 12W 4.5 ohm Non-inductive resistor 2
005-8 Mills 12W 8 ohm Non-inductive resistor 2
005-12.5 Mills 12W 12.5 ohm Non-inductive resistor 4
255-220 Jantzen 18 gauge 0.33mH inductor 2
255-414 Jantzen 15 gauge 0.68mH inductor 2
255-428 Jantzen 15 gauge 1.8mH inductor 2
027-112 Audyn 3.3 uF polypropylene capacitor 2
027-110 Audyn 2.2uF PP cap (2.35uf on schematic) 2
027-103 Audyn 0.33 uF polypropylene capacitor 2
027-432 Dayton 15.0 uF polypropylene capacitor 2
027-439 Dayton 27.0 uF polypropylene capacitor 2

About the Designer
I have been building speakers & amps, on & off, as a hobby, since 1974. I’ve created or modified roughly 26 speakers, amps, and other electronic devices over the span of the last 40 years. One of my very first speaker projects was a classic “A7″ horn type system that used a big 500Hz horn on the top and a 15” horn loaded woofer on the bottom. My brother Steve engineered and constructed the woofer horn while I cut out the big box panels. My other main hobby is photography. When attending speaker shows and events, I enjoy the challenge of using off-camera flash to create unique & interesting lighting effects across all the unique & interesting baffle boards & cabinet shapes that builders invent.

Project Parts List

Dayton Audio ES25Nd-4 1″ Ring Dome Neodymium Tweeter 4 Ohm

Dayton Audio ES180Ti-8 7″ Esoteric Series Woofer 8 Ohm

Parts Express Square Speaker Terminal Cup 3-1/8″ Gold Banana Binding Post

Acousta-Stuf Polyfill Speaker Cabinet Sound Damping Material 1 lb. Bag

Mills 4.5 Ohm 12W Non-Inductive Resistor

Dayton Audio UM10-22 10″ Ultimax DVC Subwoofer 2 ohms Per Co

Mills 12.5 Ohm 12W Non-Inductive Resistor

Jantzen Audio 0.33mH 18 AWG Air Core Inductor Crossover Coil

Jantzen Audio 0.68mH 15 AWG Air Core Inductor Crossover Coil

Jantzen Audio 1.8mH 15 AWG Air Core Inductor Crossover Coil

Audyn Cap Q4 3.3uF 400V MKP Metalized Polypropylene Foil Crossover Capacitor

Audyn Cap Q4 2.2uF 400V MKP Metalized Polypropylene Foil Crossover Capacitor

Audyn Cap Q4 0.33uF 400V MKP Metalized Polypropylene Foil Crossover Capacitor

Dayton Audio DMPC-15 15uF 250V Polypropylene Capacitor

Dayton Audio DMPC-15 15uF 250V Polypropylene Capacitor


Add yours
  1. 2
    Peter Brown

    Stunning. What a creative mind you have!! Any chance of obtaining the plans-I would love to try a build. My only transmission build was a boring old Baily box

  2. 3
    Abel Everson

    What an amazing set of speakers these not only are they aesthetically please but from what I’ve read they are sonically pleasing as well. I am also interested in building a pair, is there a way I could get at least the dimensions of them?

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