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| Driver Selection | Enclosure Assembly | Crossover Design | Conclusion | Parts List | About The Designer | ||||
| Enclosure Assembly | |||||
| I used pre-sanded pine project panels from Lowes. These are made up of edge glued 1"x2" pine strips. We used to make PA speakers this way back in high school except we had to glue the panels ourselves. The advantage of this type of construction is that the laminated wood damps well and they are not too heavy to move. I can easily pick one up and move it by myself. Now you can buy ready made panels, this is a real time saver. The side panels measure 36"x 12"x 3/4". The Top and bottom are cut from the same size panel to make two pieces 17 1/2"x 12"x 3/4". The front and back are 36"x 16"x 3/4". This method of construction only requires 4 saw cuts on the outside panels which saves time and limits mistakes. 1"x2" select grade pine lumber is used for bracing and glue blocks. I ran these full length along all joints. I also ran cross braces at about the 1/3 point from each end of each panel and above and below each of the drivers. All of these are glued flat against the panels. The cabinet is assembled using butt joints and secured with titebond wood glue and drywall screws. Pre-drill all of your holes to keep the wood from splitting. Be sure to seal the inside of the cabinet with something. I used a 50/50 mixture of glue and water on the inside of the panels and silicone caulk on the joints. For extra damping I used Acoustic damping sheets on all panels between the braces. The enclosure is lined on all sides except the front baffle with 3 1/2" fiberglass insulation. I used the new type that is encapsulated ( doesn't itch). Screw holes are filled with wood filler and sanded smooth. I cut the driver holes using a jigsaw.The speakers are painted with black lacquer spray paint. The only power tools used where a circular saw, orbital sander, jigsaw and a cordless drill. Other options for building this cabinet could include plywood or MDF. If you've got the tools and want to try another material and/or finish then go for it.
Driver Layout All drivers are mounted on the center line of the baffle in an MTW layout. Layout on 16"x 36" baffle is: From top down 3" - 7" - 18 1/2". The ports are 4 1/2" up from the bottom and 3" over from each edge. Drivers and ports are sealed in using 1/4" weather stripping. I decided to cover the area of the front baffle inside the grill frame with automotive carpet to help kill diffractions. It seems to have worked. I used a piece of black carpet 16"x 28". I tried several different driver layouts while developing this speaker and this one is the best. I don't recommend offsetting the drivers but if you decide to try it be sure to keep the Domes in a straight line. The sound suffers badly otherwise. Grills Grill frames are made from 3/4" square poplar with metal angle brackets on the corners. These are available at most hardware stores. The frames measure 17 1/2"x 30". They are covered with black grill cloth from PE that is secured with 1/4" staples. The grills are attached using Grill Guides also from PE. |
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| Crossover Design | |||||
| Crossover design was a real challenge working from a text book starting point and swapping parts. I spent nearly two weeks tweaking and listening with help from my teenage kids we finally found the magic formula. After final assembly I did extensive listening tests with friends and family. We all agree the sound is right on. |
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| Conclusion | ||
The final product is an excellent sounding mid sized floor standing speaker. Sound levels are more than enough for a medium sized room with lots of headroom. My listening room is 13'Wx 18'Lx 10'H and the speakers will shake the floor with live volume levels and with no precivable distortion at less than 2/3 power with an 80w amp. Just the way we like it. My wife and I enjoy watching live concert DVD's and have started a collection. That pastime was a driving force in this project and was fully rewarded with a sound that feels live. The speakers are used as part of a home theater system placed well away from the TV (no shielding) and work great for that as well. While these speakers where designed for rock music they also do very well with New Age, Jazz, and classical which we listen to from time to time. The sound stage is large and deep with fairly good imaging considering the wide baffle design. Trying different positions for the speakers we discovered that the sound stage is improved if the speakers are raised about a foot off the floor. YMMV I recommend at least an 80w amp for mid sized rooms, for larger rooms a 100 - 200w amp may be in order. I haven't tried higher power amps yet but I'd guess with 250+ watts these would make good DJ speakers or could even be used in a small club. I have no way of testing the speakers other than listening so all I can tell you is they sound fantastic. I would like to get them tested someday. If someone in the DFW area has the gear and doesn't mind doing it send me an e-mail. One final note, the drivers will require quite a bit of break-in time to realize their potential, especially the woofer. |
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| Parts List |
Part # |
Description |
Qty |
| 295-130 | Dayton 15" Series II Woofers | 2 |
| 287-020 | Morel MDM-55 Compact Dome Midrange | 2 |
| 277-045 | Morel MDT-37 Soft Dome Horn Tweeter - DISCONTINUED ITEM | 2 |
| 260-387 | 2" port tubes | 4 |
| 091-1245 | Gold Heavy Duty Binding Post pr. | 2 |
| 260-771 | Cabinet Feet | 8 |
| 260-367 | Grill Guides 12pk. | 1 |
| 260-335 | Black Grill Cloth yd | 1 |
| 266-365 | 1.8mh 14GA. Perfect Layer Inductor | 2 |
| 266-315 | .30mh 14GA. Perfect Layer Inductor | 2 |
| 027-582 | Solen 20.0uf Polypropylene Cap | 4 |
| 027-602 | Solen 51.0uf Polypropylene Cap | 2 |
| 027-542 | Solen 3.0uf Polypropylene Cap | 2 |
| 027-552 | Solen 4.7uf Polypropylene Cap | 2 |
| 027-564 | Solen 8.2uf Polypropylene Cap | 2 |
| 005-2 | Mills 2 OHM 12w Non-Inductive Resistor | 2 |
| 005-20 | Mills 20 OHM 12w Non-Inductive Resistor | 2 |
| 005-4 | Mills 4 OHM 12w Non-Inductive Resistor | 2 |
| 005-8 | Mills 8 OHM 12w Non-Inductive Resistor | 4 |
| 100-660 | 11 GA. Monster High Definition Speaker Cable - DISCONTINUED ITEM | 20 |
| 268-010 | Acoustic Damping Sheet 10"x 10" - DISCONTINUED ITEM | 24 |
| About The Designer | ||
| "I am 36 and live in the Dallas/Ft. Worth area. I work in the commercial construction business as a supervisor. I've been married 15 years and have 3 kids 2 of which are teenagers. I have been an avid music lover since childhood. And of course I love live rock music.
If you're wondering where the name for the speaker comes from... our house has the nickname "The Angel Fire Inn" because that's the name of our street and because of it's many teenage and other visitors that never seem to go home." |
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