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Eventide Marks 50 Years of Innovation with Retrospective Flashbacks

FOH Staff • News • February 19, 2021

LITTLE FERRY, NJ – Since 1971, Eventide has pioneered disruptively innovative ways to bend, distort and manipulate sound, remaining at the forefront of professional audio effects technology for 50 years. In 1975 the company revolutionized the audio industry by creating the world’s first commercially available digital audio effects unit, the H910 Harmonizer. Since then, Eventide’s legendary studio processors, stompboxes and plug-ins have been heard on countless major tours and hit records. Eventide® and Harmonizer® are registered trademarks of Eventide Inc.

Now, in celebration of its 50th Anniversary, Eventide is highlighting the truly groundbreaking products that first solidified the company as an audio technology leader and laid the foundation for sustained innovation across its decades of dedication to aggressively providing audio professionals and musicians with legions of products that inspire creativity. A series of Flashbacks provides a multifaceted view of these legendary products through historical insights, photos and videos and documentation excerpts.

Eventide’s PS 101 Instant Phaser was the first professional audio rackmount effects unit

Eventide’s PS 101 Instant Phaser was the first professional audio rackmount effects unit

The PS 101 Instant Phaser

The first product featured in Eventide’s 50th Flashback vignettes is also professional audio’s first rackmount effects unit: the PS 101 Instant Phaser. Introduced under the Eventide Clockworks brand in 1971, the Instant Phaser provided a swimming sonic whooshing effect developed from novel processing concepts including the notion of using the “Envelope” of the signal or a “Control Voltage” to drive the sweeping effect – concepts still routinely employed in audio processors. The Instant Phaser derived its effect from a series of analog all-pass filters and featured two “decorrelated outputs.” The PS 101 quickly became a go-to tool for both live and studio sound engineers, and its iconic sonic imprint can be heard on countless recordings.

The DDL-1745 Delay was the world’s first digital pro audio hardware device

The DDL-1745 Delay was the world’s first digital pro audio hardware device

The DDL 1745 Delay

The second Flashback in the series delves into the history of the DDL 1745 Delay, the world’s first piece of digital pro audio gear. A one-off version of the DDL had been sold to Maryland Public Broadcasting prior to its further development as a one-input, two-output commercial product with each output offering up to 200 ms of delay (adjustable in 2 ms increments). Prior to 1971, recording, film, and broadcast gear was 100% electromechanical and analog; the word “digital” had not yet entered the public, let alone the audio, lexicon. The DDL 1745 was made possible by serially deploying more than 100 of a breakthrough semiconductor chip – a 1 kb shift register – flanked with Eventide-designed digital converters (no suitable off-the-shelf converter chips yet existed). The DDL 1745 gave studios a cost-effective way to replace the ancillary tape machines used for double tracking and for pre-delay to feed plate reverbs, plus it offered the ability to produce comb filtering and effects like degradation-free repetitive sound loops. It was an instant success. Live sound embraced the DDL 1745 as well, where in a notable early application, a stack of DDL 1745s were used to time-align delay towers in a 1973 festival sound system spec’d by the Grateful Dead. In recognition of its significance to the professional audio community, the DDL 1745 was honored by being inducted into the NAMM TEC Award’s TECnology Hall of Fame in 2018.


“We’ll be celebrating our 50th Anniversary all year long,” shares Eventide’s “resident fossil/managing director” and curator of the historical Flashback perspectives, Anthony Agnello. “Over the next few months, we invite you to join us for deep dives into legacy Eventide products including the Omnipressor dynamics processor, the Instant Flanger, the H910 effects processor and its successors in the Harmonizer® line – the H949 and H3000, and the SP2016 – the world’s first general digital audio processor which also introduced the concept of the plug-in.”

The Eventide 50th Flashback retrospective of the PS 101 Instant Phaser can be found at and the DDL 1745 Delay at Subsequent installments of the Flashback series will also be posted in Agnello’s blog on the company website at

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