Pacific Northwest AES Section Blog

Past Event: Analog Tape Playback without Wow and Flutter

October 18, 2021 at 6:00 pm

Location: Virtual meeting via Zoom, Redmond WA, USA (virtual only)

Moderated by: Greg Dixon

Speaker(s): Jamie Howarth, John Chester, Plangent Processes

 Every analog magnetic recording starts with a motor dragging a rusty strip of plastic over rollers and guides, across scraping metal parts. Unfortunately, every inconsistency in the speed of the tape as it traces this obstacle course distorts the music being recorded. The transport's various imperfections create an ever-changing matrix of speed variations, slow or fast, subtle or severe.

At worst, this results in the familiar warps and warbles known as 'wow" and "flutter." It can even (as in the famous case of Miles Davis' "Kind of Blue") cause a perceptible tuning change over time.

Even the very best analog recordings - wherein the obvious wow and flutter are fairly well under control — are nevertheless affected by varying and shifting patterns of high frequency flutter, causing random beat frequencies to be introduced which seriously interfere with the natural harmonic structure of the musical material.

Until recently, there was no way to eliminate these defects and to regain the neutrality and transparency originally in the mix at the console output. With Plangent's unique combination of a wideband low-noise repro capture system and forward-thinking DSP it is possible to correct these artifacts.

What is Plangent?

The Plangent Process Playback System is a hybrid hardware/software package combining state of the art contemporary analog electronics coupled with unique digital signal processing.

It begins with an ultra-wideband low-distortion custom reproduce head and subsequent associated hand-wired preamp, followed by proprietary DSP that provides total speed stabilization and wow and flutter correction. This unique combination of integrated hardware and post-processing provides the archival mastering and preservation community a level of playback quality never before possible.

Join Jamie Howarth, President of Plangent Processes, and John Chester, Chief Transfer Engineer, as they take us through the invention and process of Plangent, with many examples of how it works.

They will show us an actual tape on an actual tape machine (remember those?) and show us the Plangent hardware capturing audio and bias. They will describe a simple case of the digital post-processing doing its thing, but some details are proprietary and won't be discussed.

The difference between the unprocessed music and a Plangent-processed version of the same music can be quite dramatic, and we'll hear examples of each.

The presentation is on Zoom (free registration through Eventbrite required to get the Zoom link; see URL), and non-Members are always welcome.

View Official Meeting Report

More Information + RSVP instructions

Posted: Tuesday, October 5, 2021

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