Spring Reverb

A spring reverb is an electromechanical device that uses a system of transducers and steel springs to mimic reflections. The reverb effect denotes a collection of delayed sound repetitions.

Some Context on the Spring Reverb

Bell Labs Company created and patented the first spring reverb device. They wanted to mimic the delays occurring over long telephone lines! These reverbs offer a very simple technique to create echo effects as they add vintage character and grit to audio tracks. It’s worth noting that early spring reverberators were used in semi-professional recordings only. Nowadays, many guitar amps use spring reverbs because of their small size and low cost.

A Little Bit of History

Around 1939, the engineers at Hammond Company wanted to add life to the dry sound produced by musical organs. In their first attempts, they used two three-long springs. They immersed them in non-evaporative oil. This was not a definite improvement, but it was better than having no reverb at all.

Years later, engineers and designers discovered that three springs gave a smoother response than only two. After several attempts, they improved the electric components of the device by applying a transducer on one end and a pickup at the other end. The transducer triggered vibrations into the springs, whereas the pickup gathered the string’s vibration and amplified it.

Around 1960, when Leo Fender added a Hammond spring reverb to his guitar, spring reverbs became commercially popular. Marshall and Peavey began manufacturing them later on. 

Spring Reverbs: How They Work

Their operation principle is quite simple. To begin with, a coiled spring is attached to the transducer that transmits vibrations. The input transducer vibrates when it gets a signal from the input. When these vibrations hit the output transducer on the other end of the spring, they are transformed to the output signal. Some vibrations bounce back to the spring and between the ends. Subsequent reflections are identical to the ones that bounce between the surfaces in one-dimensional space.

Multiple Transmission Springs

Multiple transmission springs help improve the reverb’s features. They, too, help to mimic a more natural atmosphere. This also improves the overall frequency response because one spring’s response will naturally fill the holes in the other spring’s response.

Beware!: Some Flaws of the Spring Reverb

Some spring reverb devices are not capable of adjusting the decay and other important features regarding the reverb sound. In another instance, some high-quality devices use mechanical techniques for varying the length of the decay, offering a limited degree of flexibility. Other flaws might involve the mechanical pickup of vibrations, as well as a very limited ability to handle strong transients from percussive instruments.