Flashback67 here. I am finally back with and update on the media cabinet project. Sorry it has been almost a year. But the passage of time has a way of going by quickly and unnoticed when you are busy. The house also decided on its own that replacing the two AC units, the dishwasher, and rebuilding the wood deck and all of the retaining walls around the house took precedent over my audio system project. But this is an audio site, and I am ready to discuss fun stuff.
Over the past year I have spent many hours sketching different speaker configurations for the media center. Most of them utilized the Altec 604 coaxial as the basis. I started off trying to keep some of the electronics in the two side areas behind the hinge screens. But I came to the conclusion that it was best to make use of all the volume on the sides and relocate all electronics to the area above the TV. This area is nice and deep, ventilated, and can be totally hidden by two doors that slide out from either side to disappear when open. This also gives me the freedom to change electronics more easily should I want to play with different amps, preamps or sources.
I thought I would try to fit an MTL configuration into the space available. And while I could just about make it fit, the compromises I needed to make did not guarantee success. While volume was adequate, port location and cross-sectional area we’re not optimal. Going back to a conventional bass reflex design was the best option. But I was hoping to get deeper base in the conventional 604 would get in a bass reflex cabinet. Also the 604 tweeter height was a little bit taller than my seating height on the couch. Without electronics in the area I could mounted lower, but the screens on the doors have woodframe bars that would block the tweeter with the door closed. So a complete re-think was required.
I had been reading a lot about the Altec Model 19, and had heard only good things. So using the dimensioned drawings I found of the Model 19 cabinet My plan changed course. Using the modern GPA 416-8B in a 8.8 cuft bass reflects cabinet gets me a respectable 25 Hz bottom end. While installing the the Altec 811-B horn below the 416 can get me the tweeter height closer to optimal. Reading the Model 19 manual I even discovered instructions on how to position the cabinets upside down for studio use. As a final bonus, the drivers clear almost all the screen obstructions.
I was looking for some karma sign to tell me this was the best direction to go with the cabinet design. The sign came from an ad on eBay for Altec 811 horns for sale in perfect original condition, and just 15 minutes drive from my house. Within one hour of seeing the ad I purchased the horn’s and brought them home. They were just as described perfect condition and they only cost me $90. In seeing these huge aluminum monstrosities my wife commented “Well if you don’t use them for the speakers, I can make them into some very interesting flower vases”.
Over the past year I have been putting aside funds for this project. Last week I spoke with Bill at GPA and told him I would be putting in an order for all the parts I needed within the next few weeks. Oklahoma City is just a 3 hour drive North for me. So I can pick up all the components and save both shipping and worry.
Now I need some input and comments from the audio karma community. Please take a look at the attached plans and let me know what you think. I am especially interested in any comments regarding the port location and size, placement and type dampening material to use, and any thoughts concerning cabinet rigidity. The top, bottom, and sides of the cabinets are 1.5” furniture grade plywood. The front and back of the cabinets will be 0.75” furniture grade plywood with 0.75” MDF bonded to it. I am thinking that with this thickness there is no need for any internal bracing. But I need some reassurance.
In looking for boards to use with the right veneer, I actually found another treasure trove. There are enough good boards for me to build matching shelving for the electronics I plan to use. The electronics is another discussion for another post. I have some ideas for modern equipment, but they may be full of Shiit.