| Speaker Modification and Restoration Projects |
| For quite a few years, I have been involved in the contruction, restoration, modifaction and design of home, car and professional loudspeaker systems. I spent a 10-year period as a car stereo installer, working for several shops in Moultrie GA and the Atlanta GA area. I have also built PA/theatre speakers for Anime Weekend Atlanta, a Japanese animation convention (of which I am one of the founders and the tech director), and built various speakers, for DJ systems, for other people as well. Myself and a college chum, Robert Cheng, are planning to start a business, creating and building our own line of home audio/home theatre loudspeaker systems. We are currently in the design stage of several prototype speaker systems, and have purchased a $2400 Linear-X LEAP/LMS loudspeaker modelling and testing system to aid in design optimization. This type of equipment is a great addition to critical listening as a tool in tuning out and "voicing" speaker systems! I also work at Audio Atlanta in Marietta GA, where my primary job is the restoration, upgrade, modification and repair of loudspeaker systems brought in by customers. Here are a few pictures of projects I have worked on, there. |
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| Advent 1 (circa 1977) |
| These are a pair of vintage Advent 1s, which came in needing pretty much nothing other than the replacement of the foam surround, on the outer edge of the woofer cones. This foam, especially the older compositions of 20 or more years ago, tends to dry-rot, and eventually will crumble and fall apart, leaving the cone un-supported on the edge and leading to rattles, buzzes and a general lack of bass response. However, it's an extremely simple and relatively inexpensive problem to rectify- all that is necessary is to clean away the old foam residue, procure a replacement foam surround of the appropriate size, composition, and stiffness (basically detemined by the thickness of the foam material), and glue it in to the cone and speaker basket. The only big consideration is getting things aligned properly so that the cone and voice coil are centered and the voice coil doesn't drag in the magnet motor gap, but even this gets to be pretty easy with practice. These speakers are shown after this procedure was completed, and will probably be good for another 20-plus years of satisfactory service! |
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| Mission 707 Cone Assembly- Before and After |
| This is a picture of the woofer moving parts from a pair of British-made Mission 707 loudspeakers from the late '80s, in the middle of a process called re-coning. In this process, the entire moving assembly of a blown loudspeaker driver is replaced. Basically, everything is removed except the speaker basket (the round frame that everything mounts to) and the magnetic motor assembly. Shown above on the left is the old, blown assembly from the Mission woofer (note the utterly annihilated and smoked voice coil!), and on the right, the new assembly that we created to replace it. A new moving assembly was built up from a cone, a surround (as described above, the flexible "ring" on the outside of the cone), a voice coil, and a spider (the tan corregated ring on the outside of the voice coil, which supports the coil and centers it to the basket). New flexible wires are installed between the coil and the terminals (these are the two leads coming out of the sides of the cone assembly, above), and the whole assembly is aligned and glued into place in the cleaned-out basket/magnet assembly. Voila- like new loudspeaker! |
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| EPI M100 (circa 1971) |
| These are a pair of EPI M100 loudspeakers, that I rescued from a dusty oblivion in a pawn shop. They had some rather serious problems- not only was the surrounds rotted in both, but one of them had been dropped hard enough, to break the magnet loose from the woofer basket! To repair this, I removed the cone assembly (same as reconing, except I actually managed to non-destructively remove it so as to be able to reinstall and reuse it- I even managed to re-use the spider, which is usually considered to be near-impossible), created shims to align the magnet to the metal plate on the woofer basket, glued the magnet assembly back on, reinstalled the cone assembly, and glued in a new surround. After this restoration, they are some really good sounding speakers, especially to be over a quarter-century old! All hail Winslow Burhoe (founder of EPI)! |
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| ElectroVoice Interface 1- Exploded View |
| This is one of a pair of Electrovoice Interface 1 speakers, in progress. These were purchased on Ebay by a customer of Audio Atlanta, and were brought in due to some rather anemic bass response. We found that the passive radiator (the large loose cone above- like a standard speaker except without a voice coil or magnet assembly- used as a sympathetic resonator to reinforce the woofer's bass response) had come completely loose from the back of the cabinet (its spider mounted on the large "ring" inside the cabinet hole, above), and the radiator cone had then become cocked and jammed, preventing it from moving and severely restricting the bass output of the system. We re-did the passive radiators with new surrounds (they had been replaced before, but it was by far not a very neat or sturdy job!) and a good re-gluing job to the cabinet. With this, and some very basic crossover upgrades (we added some polystyrene film capacitors to "bypass" the large capacitors in the crossover, giving a slightly more "airy" treble response), these blossomed into one pretty darn incredible sounding pair of speakers, with bass astoundingly tight, deep (they went down to 30 Hz!) and potent for such a small speaker system (they're barely 20" tall, 14" wide and 6" deep) with only an 8" woofer and a tweeter! |
| For more info on loudspeakers and loudspeaker repair, here are a few good resources: |