Reverberation and echo set the tone for a sound recording, just as descriptive sentences set the tone for a novel. They establish the place and space of a recording telling us where it is coming from.
Over fifty years ago, old school engineers used to use small spaces that had a lot of natural reverberation; i.e. long hallways, tiled bathrooms, shower stalls and that space under staircases, to capture the reverberation effect.
Then in an effort to control echo, engineers designed and installed a dedicated, controlled space solely for the purpose of adding echo; live echo chambers. Generally 10’x15’ with a low ceiling, these chambers are designed to be highly reflective, often times crafted from concrete or tile.
Many engineers argue that the well-built live echo chambers produce a reverberation source that is unparalleled, even by todays standards.
In the 1950s through the 1970s, came the simulators; echo plates, spring reverbs and tape-echo units.
The echo plate is a device for electronically generating reverberation. This device simulates the sound of live reverb by sending a recorded signal through a transducer to mechanically vibrate a long metal plate housed within a large protective enclosure. Then a couple of contact microphones picked up the vibrations and converted them back into audio signals.
Spring reverb units, like echo plates, use transducers attached to the end of a generous length of wrapped spring coil. They are a bit smaller that the plate reverb and for a few sound applications were considered more desirable than plates. Some engineers believe that if they are set up right they tend to sound like live echo chambers
Tape Echo replicates the reflections found in reverberant rooms. Sometimes this is accomplished by using a second machine, as well as, manipulating the speed of the tape, thus increasing the length of delay. A more sophisticated form of tape echo uses multiple heads for multiple echos. Tape echo works best when used as part of an actual recording session.
Today, there are digitally processed reverbs that provide engineers with convenient and predictable reverb at the touch of a button.
However, engineers who create new music today with a past perspective tend to favor old-style machinery. The mixes just sounds better. Says Andy Babiuk, a NY based recording engineer and author of Beatles Gear: All Fab Four’s Instruments, From Stage to Studio; “There is a physical thing that happens when you’re using something truly analog like a plate – things never quite happen the same way twice, simply because it’s a physical process.”