EMT 140 Plate Reverb by jml designs
An industry classic. I used them extensively at Electric Lady Studios where they are normalled into the SSL's in all studios (I only used them in Studio A and B though). Nothing folds into a mix better than the real thing although the plugin is my go to ITB verb.
When these first came out they were $9,000 and immediately knocked off for around $3000 by many other competitors. The ability to reposition the elements using servos and motors is a huge plus but these days plugins can achieve similar results with a DIY plate. I built one by using cold rolled 6 foot steel sheet pulled tight with turnbuckles on a metal frame (do not use wood!). Using cheap piezo pickups and a 6" speaker driver I was able to get really close the this EMT although the added features of the original and the sound is not the same. An incredible addition to any studio for sure. The ability to mix sources that have been processed with this EMT are astounding. Some old EMT's rust and need to be cleaned, some had gold foil which gave them different sounds but this one employs a stainless cold rolled steel to my memory.
Nothing is cooler than visiting the attic of any prominent studio and quietly listening to the vibrations of sound shimmer across the plate as an artist, floors below you, are tracking in the live room. These things are pure magic and a staple of the recording industry. So... since you're not going to buy one, make one!