Newsletter Issue #10: Plangent

How a forgotten ultrasonic signal is bringing the 1960s back from the dead.

SET I: The Problem — Analog Tape Is Dying

Every analog tape ever made is degrading right now.

The problem isn't just age. It's physics. Magnetic tape suffers from:

• Wow and flutter—speed variations that destroy pitch stability
• FM modulation distortion—a harsh, cloudy grain that even the best tape machines introduce
• Binder hydrolysis (sticky-shed syndrome)—the adhesive holding the oxide to the backing breaks down, making tapes literally unplayable

Even if you could freeze a tape in perfect environmental conditions, you can't escape the fact that every playback degrades it further. The act of listening destroys the thing you're trying to preserve.

For decades, archivists faced an impossible choice: transfer tapes now and accept the degradation baked into the medium, or wait for better technology and risk the tapes becoming unplayable.

Then Jamie Howarth discovered something everyone had missed.

SET I, Act Two: The Hidden Map

Every analog tape contains a hidden ultrasonic signal that maps its own degradation.

It's called the bias signal—a high-frequency tone (typically 100–200 kHz, well above human hearing) that was recorded onto the tape during the original session to optimize magnetic particle alignment. It was supposed to be a constant frequency.

But here's what Howarth realized: any variation in that frequency is a direct measurement of the tape transport's speed errors.

If the bias was recorded at 150 kHz and now plays back at 150.2 kHz, that's not because the bias changed—it's because the tape speed fluctuated. The bias signal is an ultrasonic forensic record of every mechanical imperfection in the original recording and every subsequent playback.

Howarth's insight: if you can extract that bias signal and reverse-engineer the speed map, you can time-warp the audio back to what it was supposed to be.

That's Plangent Processes.

SET II: The Mechanism

Here's how it works:

Step 1: Ultra-High-Frequency Playback

Plangent uses specialized head stacks with frequency response flat to 1 MHz—far beyond what normal tape heads can capture. This recovers the ultrasonic bias signal that conventional transfers simply discard.

Step 2: Pitch Mapping

A DSP routine (written by mathematician Patrick J. Wolfe) translates the varying ultrasonic signal into a pitch map—a frame-by-frame record of exactly how fast or slow the tape was moving at every moment.

Wow and flutter aren't random. They're measurable, ranging from several Hz (slow tape warble) to beyond 4 kHz (fast flutter). The bias signal captures all of it.

Step 3: Time-Warping

Once you have the pitch map, you can apply time-warping—stretching or compressing the audio in the opposite direction to reverse the mechanical artifacts.

This isn't interpolation. It's not guessing. It's using the tape's own embedded reference signal to reconstruct what the original performance sounded like before the machine introduced distortion.

Step 4: Ultra-High-Resolution Capture

Plangent digitizes at up to 384 kHz / 32-bit through Mytek and Prism ADCs, preserving detail that would be lost in standard 44.1 kHz / 16-bit transfers.

The result: the harshness, cloudiness, and grain introduced by FM modulation distortion are removed, while the pleasant harmonic distortions that give analog tape its warmth are preserved.

You get the tape sound you wanted, not the tape sound you were stuck with.

DRUMS/SPACE: The Bear's Sonic Journals Proof

The Owsley Stanley Foundation has been using Plangent Processes to transfer Bear's Sonic Journals—the 1,300+ reel archive spanning 80+ artists from the 1960s–1980s.

The results have been stunning.

Critics are saying Owsley's tapes now "eclipse" the commercial live releases from the same era:

• Americana UK on the Johnny Cash at the Carousel Ballroom recording: it "eclipses the live albums released at the time."
• Audiophile Review on the Allman Brothers Fillmore East recordings: the clarity is "not as distinct" in other recordings from the same era.

This isn't nostalgia. It's measurable fidelity improvement.

The Plangent transfers are revealing detail and spatial information that was always there but unrecoverable until now. Owsley's original analog captures contained levels of nuance that only modern transfer technology could fully extract.

The irony: Owsley's obsessive pursuit of live sound purity in the 1960s is only now being fully validated, because the technology to prove what he heard didn't exist until 50 years later.

SPACE: The Preservation Emergency

Here's the urgency:

The Owsley Stanley Foundation holds 1,300+ analog reel-to-reel soundboard recordings. As of 2024, approximately 900 reels (~69%) have been processed. That leaves roughly 400 reels (~31%) still awaiting digitization.

The problem: the typical shelf life of analog magnetic media is approximately 50 years under ideal storage conditions.

The earliest recordings (1966) are now 58–59 years old—already past that threshold.

The Foundation has been told the oldest tapes must be digitized "within the next five years" or they will become unsalvageable.

The cost: $300,000–$400,000 and two full-time engineers working for two to four years.

The Foundation is entirely volunteer-staffed and relies on donations and release proceeds through its "Save The Music!" campaign. At the current release pace of 3–4 titles per year, revenue generation from commercial releases alone is unlikely to fund the full digitization at the speed required by the degradation timeline.

This is a genuine emergency for the ~400 unprocessed reels, which likely include some of the oldest and most historically significant material.

I think about this every time I listen to a Bear's Sonic Journals release. Somewhere in that archive is a Miles Davis soundboard, a Hendrix show, maybe a Thelonious Monk set. And it's all racing against the clock.

ENCORE: What's Sitting in the Archive

The unreleased Bear's Sonic Journals reels include known but unissued recordings by:

• Miles Davis (opening for the Grateful Dead—an undocumented chapter of his electric period)
• Jimi Hendrix (potentially one of very few soundboard recordings not controlled by the Hendrix estate)
• Thelonious Monk (late-1960s live soundboards are exceptionally rare)
• Janis Joplin / Big Brother and the Holding Company (raw SF-era sound in potentially superior fidelity)
• Fleetwood Mac (likely Peter Green era, with limited official live documentation)

Plus extensive Grateful Dead material, Santana, Jefferson Airplane/Starship, Quicksilver Messenger Service, Taj Mahal, the Flying Burrito Brothers, Old & In the Way, and Blue Cheer.

The ten Bear's Sonic Journals releases to date have repeatedly filled highly specific and previously unfillable gaps:

• Earliest-known performances (Allman Brothers' "In Memory of Elizabeth Reed")
• Only-known originals (Tim Buckley compositions)
• Hours of unreleased repertoire (New Riders material never released by either NRPS or the Dead)

If the pattern holds, the unreleased reels likely contain additional "only-place-on-earth" soundboard-level evidence of major artists—potentially rewriting or materially extending accepted discographies for figures as large as Miles Davis, Hendrix, Monk, Joplin, and Peter Green–era Fleetwood Mac.

But only if the tapes are transferred before they degrade past the point of recovery.

The technology exists. The tapes exist. The clock is running.

If you want to help: [Owsley Stanley Foundation — Save The Music!](https://owsleystanleyfoundation.org/)

Sources:

• Plangent Processes technical documentation (Jamie Howarth, Patrick J. Wolfe)
• Owsley Stanley Foundation archival status reports
• Bear's Sonic Journals release series (10 chapters to date)
• Critical reception: Americana UK, Audiophile Review
• Preservation timeline estimates and cost projections

This is Newsletter Issue #10 in an ongoing series exploring the hidden infrastructure of the Grateful Dead's sound and Jerry Garcia's creative ecosystem.