Pickups All the commercial units use Piezoelectric pickups or accelerometers. These are basically contact mic/pickups and are available from several manufacturers. As a matter of fact, you probably already own one, or at least know someone who does. Some examples of available units are those from Barcus-Berry, Fishman, and Frap. Some pickups need no preamp and can be plugged into the echo return(s) on your board. You can also return the output of the pickups through two mic inputs on your mixer, using a tube, discrete class A, transformer or transformerless (differential), FET, IC DI. These are some of the variables that you must work out depending on the console you own, and the pickups you use. Try as many pickups as you can borrow until you find one that you like and that easily interfaces with your mixer. For a mono reverb, place the pickup near one of the side frame reinforcements. Experiment by moving the pickup up around, and down, on both sides of the reinforcement, until you find the spot you like. Then secure the pickup by epoxy, wax, putty, or whatever the pickup manufacturer recommends. Run the pickup wire down the reinforcement, again using "ty--raps" or tape. For a stereo unit, do the same thing on the other side (Figure 8). *[After much research and development, we have found the pickups, and preamps that work best, and are the most cost effective.] *
Tuning the Plate With the pickups in place, the plate itself now comes into focus for tuning. In theory, think of the plate as similar to a drum head. Also, correct tuning means all the lugs are equally tensioned. So, start by holding the hooks suspending the plate in the frame with a pair of "vice grips" or similar pliers, and tighten the nut on that hook with a ratchet wrench. Do this evenly around all eight hooks. How do you know when the plate is tuned? Good question. You don't, really, because every manufacturer used their own method for tuning. EMT shipped units pre-tuned except for four nuts, which were supposed to be tightened by exactly 1/4 turn when installed. Most independent EMT servicemen will tell you to tighten each one until a spring suspension clip breaks, and then replace it and tighten until 1/8 of a turn before it breaks again! Lawson and Audi-ence shipped their units pre--tuned, no adjustment necessary. Ecoplate supplied a spring gauge and specified pushing the gauge against the plate at all eight plate tensioning points, until there was approximately 150 pounds of pressure at each point. As a total contrast, Stocktronics used no tuning at all, claiming the steel was pre-stretched/tuned during manufacturing. In fact, their plate was simply suspended by six springs in a very light aluminum frame. Which method is correct? Any/all/none, depending on your point of view. One thing is certain, though. If you like the way it sounds, it's right. So I suggest tuning by ear. Remember, the tighter the plate, the tighter the bottom. It is usually better to over-tension than under-tension. Also, listen for "flutters" or "beats" (like two slightly out-of-tune guitar strings) on the decay of the reverb, and even-out the tension until they disappear. EMT warned about the "oil can effect," a very metallic sound that is heard on an obviously out-of-tune plate. What I suggest is to find an existing plate you like in a studio near where you live. Rent an hour of time, and bring along a tape of various tracks-snare alone, drum kit, congas, tambourine, voices, piano, and run it through the plate. Record the reverb return on one track of a two -track or cassette, and your original dry signal on the other. Bring it back to your place and pan the dry signal to the center of your monitors, and the reverb send from their plate on the right. Send the dry signal to your plate, return it to your mixer, and pan it to the left. Now you can directly compare your plate to theirs, and tune and equalize until the sound of yours equals or betters theirs (subjectively)! A CD like this is available, made using both an EMT 140 ST tube unit-the "classic plate" sound, and a plate made utilizing the techniques and parts described in this article. To hear what the finished product will sound like, listen to some MP3s of the one we built using the components we found sounded best. Go to this link www.errico-associates.com and click on the picture of the plate. Notice the deep, smooth bass, and crisp, sparkling highs-as well as smooth decay. Sends chills up your spine, huh?) Use your ears and you can't go wrong. Talk Plate Reverb with Bob
Buontempo in his PSW Rec Pit forum.
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