Designer:
Javad Shadzi

Project Category:
Tower Speakers

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
Over $1,000

Project Description:
The EPQ-3W is a high end build utilizing Dayton AMT Tweeters and the new 8″ Epique E220CF-8 with carbon fiber cone and high strength neo driver. The goal for this project was to product a dynamic 3-way founded by the 8″ up to 1khz and handing off the snappy and dynamic AMTPRO-4, and featuring exotic materials and a carbon fiber theme.

Design Goals:
The design goals for EPQ-3W were:

– Detailed, accurate flat response

– Efficient and dynamic response, fast transient behavior and sound

– Good dispersion characteristics

– Beautiful to look at

Driver Selection:
AMT2 Supertweeter

AMTPRO-4 Tweeter/mid

Dayton Epique E220CF-8 Woofer

Enclosure Design:
There are two enclosures for the EPQ-3W, the first is the sub enclosure for the open back AMTPRO-4, the purpose of this enclosure is to capture the back wave of the AMT, dampen it and diffuse is. This enclosure is “v-shaped” to minimize the propagation of surface reflections inside the enclosure, then heavily damped with denim insulation material.

The enclosure for the woofer is ported with an internal volume of 1.6 cubic feet, with a 3″ port tuned to 31hz which provided flat in room response to approx 30hz and good extension to 20hz. This enclosure is dampened with denim insulation behind the area of the woofer to dampen the response of the back of the cone.

Enclosure Assembly:
The base enclosure is constructed from 18 ply Russian Birch, similar to Baltic Birch but completely void free and very dense. Baffle, back and top are “veneered” with 3/4″ Chechen wood from South America, a very dense wood with beautiful grain.

Some brad nails were used for initial assembly of the Birch ply enclosure, all other construction is with Titebond 2, 3, Polyurethane glue and dowels.

All drives are flush mounted to prevent any diffraction, baffle edges have a generous 1.5″ 60-degree bevel to minimize diffraction as can be see in the off axis response below.

Crossover Design:
The crossover is a fully passive design

Woofer – 1.15k low pass 12db electrical, polarity reversed

Mid/Tweeter – 1.15k high pass 18db electrical, 9k low pass 12db electrical

Super Tweeter – 9k high pass 12db electrical.

All capacitors are high quality poly sourced from Parts Express, air core inductors are used except for the larger 3.0mH inductor on the woofer in order to reduce resistance as much as possible.

The AMT’s are not flat and a challenge to work with, it’s worth it as they sound fantastic, my recommendation would be to match my baffle dimensions and steal my schematic, I got these drivers to work very well together and operate very flatly.

Tips & Tricks:
Copy my crossover or use the AMT’s with an active DSP

Have fun and learn something!

Google “Javad EPQ-3W” to learn more about this project and to see a detailed build thread

Conclusion:
Every new project for me is an exploration in some new concepts and ideas that I hadn’t tried before, the EPQ-3W project gave me new experience in building a trapezoidal shaped cabinet, working with Chechen wood, Carbon Fiber veneer, using the new Dayton Audio Epique E220CF-8, using an 8” hifi driver up to 1000hz, using AMT tweeters, implementing a super tweeter and a few other things as well.

This was a really fun project and I’m definitely coming away with some new skills, ideas and experience to apply to the next project. These ultimately were for the Midwest Audiofest event in July and they were well received and placed 3rd in Dayton category which I was pleased with considering the stiff competition. Visually the Chechen wood is stunning and I like the contrast with the Chechen wood, but also the parity to the carbon fiber theme including the woofer cone and binding posts.

I love real wood, each board and each grain pattern tells the story of the tree’s life and what it endured to continue to grow and thrive. I love looking at each baffle while I’m listening to these, taking in the differences, imaging what these two different trees experiences that made them grow the way they did.

Sonically these sound great, the AMT tweeters are a challenge to work with passively crossed over as they do not have a flat response, but I was able to get a very flat response considering what I started out with. I purposely left the super tweeter elevated above 10khz as it gives the speakers a nice air and detail to the sound. I tested 6 different crossover topologies before finalizing on what is here, this project would be super easy to do with an active DSP and yield very good sound as well.

The Epique woofer is a good unit, tuned to 31hz in about 1.8ft^3 it provides deep bass to 30 he in room. It holds its composure to over 300 watts with bass heavy tracks, I have measured these speakers at over 110db at 1-meter with my Adcom GFA-5800 clipping lights flashing. In my listening design room imaging is holographic with excellent off axis response virtually anywhere in the room.

About the Designer:
Javad Shadzi is a business owner of company that manufactures automotive performance products, he has 4 kids and a wonderful wife and he resides in the Bay Area of Northern California. His wife is thrilled with all the speaker projects he has planned, in fact she can’t wait to see the next ones he builds!

Project Parts List: