Eventide Marks 50 Years of Innovation with Retrospective Flashbacks

For 50 years, Eventide has pioneered disruptively innovative ways to bend, distort and manipulate sound. 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.

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 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 break-through 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.

“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 https://www.eventideaudio.com/blog/aagnello/50th-flashback-1-ps101-instant-phaser and the DDL 1745 Delay at https://www.eventideaudio.com/blog/aagnello/50th-flashback-21-ddl-1745-delay. Subsequent installments of the Flashback series will also be posted in Agnello’s blog.


  1. wow wow wow – memory lane.
    When I was 15 years old, I saw an ad in the back of the Village Voice in NY by some guy (Ken Bishell) that was giving free ARP synthesizer lessons. I begged by father to drive me to his apartment in Manhattan, so I could get free synthesizer lessons. Ken was a studio musician at Atlantic Studios in NY City. I asked him if I could come visit him at Atlantic, and he said “sure”. That was my first time in a recording studio, and I saw the giant MCI multitrack console. I said at that moment “this is what I want to do for the rest of my life”. I was now smitten with professional audio gear, and I once again begged my father to drive me to the Jamica, Queens public library, where they had copies of the AES (Audio Engineering Society) magazines. As I browsed thru the magazine and the ad’s, I saw a company that was in NY – in Manhattan. It was Eventide Clockworks. I took the train into Manhattan, and banged on the door at 265 W 54th Street. Eventide was a tiny company, and I met Richard Factor. I guess he was intrigued that this little kid (me) was interested in his company, and he showed me around. I saw on the wall behind his desk, all the pictures of him with all these rock stars that were using Eventide equipment. That was it for me. I knew I had to do this for a living. That must have been 1972 or 1973. And here we are today in 2021. Eventide was legendary even back then.

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