The Crossover

Thanks to Wayne J. at Speakerbuilder.net I didn't have to worry about designing a crossover. From reading about the experiences with several of his other designs (D3's, VD Monitor and DHT) I could not think of a better way to go and would build these as proposed. 

Parts List

Below you will find my suggested list of parts for the DJ8MTM all from Parts Express...

Notes

Parallel the 50uf and the 22uF to make the 72uF cap
Use the 15uF for the 16uF
Use the 7.5uF for the 7.2uF
Use the 12uF for the 11.5uF
Use the 2.4 Ohm for the 2.5 Ohm
Use the 4.7 Ohm for the 4.5 Ohm
Use the .4mH for the .45mH
Use the .33mH for the .35mH
 ***You may notice that some of the parts aren't exactly as specified in the crossover. That's OK as they are close enough and this will not produce any difference audibly.

The Cabinet

If you don't have a large listening area, you might want to build a different speaker. I have these things in my living room and they are large indeed, they need their own postal zip code. OK now here are the specifics:

The internal dimensions of the cabinet are 49” x 16.5” x 9.5” (around 4.4 cu. Ft). I used (3) 7"x9.5" braces inside the cabinet to try to tie the sides together. You could brace more if you wanted but it is not necessary. A tuning of 32 Hz was employed to get the lowest F3 and flattest response possible. If you build the cabinet as described. just use a PE 260-328 port in it and you will be dead on. If you want to make one out of PVC pipe and save 30 cents, make it 4" ID x 4.5" long. The driver spacing that I used left 3/4" between the woofer frame and the tweeter face plate. The tweeter is offset 3/4" also. The sides and the rear baffle are covered with egg crate foam. There is also about 1/2 pound of Poly Fill behind the drivers. I also used (not in parts list) some vinyl floor tile from the local hardware store and adhered them to the interior to even dampen the cabinet even more. I should draw some sort of diagram for the cabinet but you should be able to figure it out. The crossover was mounted to the outside rear of the cabinet. I utilized a Radio Shack black plastic project box for each. They had to be rather large as the crossover when built takes up some space. I felt this was better in keeping things cool and easily accessible for future tweaking if needed. The external finish was very involved and took as much time as the box construction. I used 15 coats of a satin black latex mixed 50/50 with a satin clear latex sealer and rolled it on with a very fine foam sponge roller and steel wooled between each coat. The effort was worth it for the finish is smooth, satiny and very durable.

How do they sound?

These things definitely sound real, dynamic and definitely rock hard. You do not need a subwoofer with these monsters, just a cold brew, some Jack D and a copy of the "Lamb" CD/album by Genesis. The sound is like I have never heard in my living room. The bass rattled things off of my fireplace mantle without a hint of sounding strained.

On the serious side though, these things do sound fantastic and lifelike. I put on an Eric Clapton live CD and he sounded like he was in the room. Another quality of these speakers is the unbelievable wide stereo image they project. Even when standing beside them you never loose the other channel. As a package these are possibly the best all around deal I have seen in DIY speaker projects. For around $160 bucks in parts you can really wake up the neighborhood. Check out at my other site and sign the guestbook. Intruder LC 1500

General articles

• A look at other panel type loudspeakers and the LFT design - each distinct type of panel loudspeaker has its own unique set of pros and cons

• A practical guide to acoustical design of control rooms and placement of loudspeakers

• Direct vs. Reflected Energy

• Dynamic Loudspeaker Principle and Loudspeaker Basics

• Electromechanical Audio Indicators and Transducers - basic information on speaker drivers and relate devices

• Linkwitz Lab - The site contains material about loudspeakers, room acoustics, crossover and system design, as well as detailed construction plans for the PHOENIX active open baffle loudspeaker system

• Loudspeaker Basics

• Loudspeakers Primer - introduction to loudspeaker technology

• Matching the right loudspeaker with a given application requires an examination of some essential electroacoustic parameters

• Outdoor Speakers: Rocking in the Great Outdoors - Special speakers permit distributed audio in front and backyards with low sound levels.

Speaker placement tips

• Loudspeaker Spatial Loading - the frequency response of a loudspeaker system depends on how the system is "loaded"

• Principles and Techniques of Speaker Placement - information is based on scientific research and observations of Audio Physic and some of their most successful dealers

• Speaker Placement for Surround Sound and Whole House Audio Systems by JBL

• Sub-woofer Purchasing, Positioning and Calibration

• The Audio Physics Method of Speaker Placement in Room

• WASP: speaker placement made easy - describes speaker positioning methodology called Wilson Audio Setup Procedure

Speaker product information

• Links to loudspeaker manufacturers

• The Bose FAQ - what rec.audio.* newsgroup users think of Bose speakers

History

• Accomplishments, History and Legacy of James Bullough Lansing - his name is carried on in the corporate identity of two companies, JBL and Altec Lansing

• Ulrich Haumann's Vintage HiFi Pages: The Home of Plasma Tweeters - This homepage is dedicated to all that old Tube Hi Fi, specially Leak, Quad, Elektrostatic Speakers and Plasma Speakers

 

Speaker wiring and hookup info

• Basics of wiring Speakers

• DIY Speaker Wire Note by Jon Risch

• Equal Length Speaker Cables - Are They Necessary?

• How To Choose Loudspeaker Cable - loudspeaker cable size recommendations in both USA traditional wire gauge and European square millimeters

• How to connect your loudspeakers - basic wiring information

• How To Choose Loudspeaker Cable - This document gives you information on cable selecting and impedand impedance curves of some loudspaker cables.

• Loudspeaker Protection - the problem of how to protect speakers is a difficult one with no universal solution

• Loudspeaker Protection and Muting - information and circuits

• Series Box Project - Suppose that you have two identical speaker cabinets that you would like to hook up in a series connection. Here is a simple box to allow you to do this.

• Skin Effect - skin effect is a physical phenomenon that relates to the limited penetration into a conductor of a high frequency signal according to its frequency

• Speaker Cable Considerations and High Performance DIY Speaker Cables from Commercial Wire - DIY Speaker Wire Note by Jon Risch

• Speaker Connections - Information how you can wire more than one speaker for different impedances.

• Speaker Wire - history and information

• Speakon - A type (and brand) of multi-pin connector developed by Neutrik which is now commonly found on speakers and amplifiers intended to be used in high power mobile applications.

• Speakon connector datasheet

• Speakon Loudspeaker Amplifier Connectors

• The BFA Loudspeaker Connector

• The Rec.Audio.FAQ Cable Overview

• The Science of Spaker Cable Design - series of articles from TARA Labs appeared in Stereophile magazine

• The UBYTE-2 Speaker Cable - idea how to make your own speaker cables