Forgotten audio formats: Wire recording

It’s bizarre but true: wire recording is the longest-lasting capture format in audio history, one that paved the way for reel-to-reel tapes and a host of others—even though most people today, and some techies included, have barely heard of it.

Invented way back in 1898 and patented two years later, wire recording was somehow still getting some limited use as late as the early 1970s, while rockets took man to the moon on an annual basis. In its wake, vinyl, with its 67 years, and CD with a mere 33, look like footling youngsters. In its none-too-brief life, “the wire” also found use in Hollywood, provided a broadcast aid to spying, helped launch digital data capture, and pioneered the new art of bootlegging—sorry, “home recording.”

Wire was longer-lasting in other ways, too—whereas shellac and vinyl records would only last a few minutes per side, and the first commercial tape decks weren’t that much better, the wire recorder could get down over 60 minutes of audio.

Hanging on the telegraphone

Of course, it didn’t start that way. The earliest wire device was cooked up at the end of the 19th century by one Valdemar Poulsen, a Danish-American inventor who, five years later, developed the first continuous-wave radio transmitter. This first “telegraphone,” as Poulsen dubbed it, was somewhat crude, but it did have the key conceptual elements: a metal wire was pulled between spools across a recording head, which magnetised the wire in accordance with the sound signal it was receiving at that moment. In other words it recorded recognisable sound.

The American Telegraphone Company then cranked out various dictation machines, which, in terms of quality, beat the hell out of their wax cylinder rivals. And, unlike the cylinders, wire reels could be used and reused time and time again and were capable of recording for far longer. Wire recorder sales were steady but not spectacular; it was not a machine most small businesses could afford. Quality-wise, too, neither wire nor wax cylinder could come anywhere near capturing the wide dynamic range that music requires. So as 78rpm shellac records slowly but surely improved, the musical applications of wire were increasingly neglected, although they did, strangely enough, make a late comeback.

But later on, during the 1930s and again in World War II, the secret services of several nations would use wire recordings, massively sped up, to broadcast on shortwave radio to their agents in the field. The agents would be standing by, ready to “wire tape” these broadcasts, already aware of the exact tempo to play them back at. Of course, the enemy could sometimes decipher these broadcasts if they had enough experts and wire recorders with which to try speed experiments, but they were difficult enough to translate to give the receiving operatives at least a day or two head-start. For anything urgent, it was for years the simplest way of broadcasting something your agents could swiftly understand that the opposition couldn’t.

And then, after World War II, the wire—by now middle-aged—finally entered its golden age, a decade of near-dominance because wax cylinders were long gone and the new, early, tape decks were far too expensive for anyone except the rich or top sound studios. So American manufacturers Armour and Brush licensed dozens of improved wire machines across North America, Europe, Australia, and Japan. They became the kings of dictation and, later, family recordings.

One mile per hour

Most of these post-war wire machines used a speed of two feet, or 24 inches, per second (610mm/s), so an average hour-long recording would use up a spool of wire that was 7,200 feet in length (2,200m). That’s well over a mile long, roughly 1.35 miles in fact, but this huge length could easily be squeezed onto a reel less than three inches (76 mm) wide, as the wire—by then made of stainless steel—was incredibly fine, with a diameter of just 0.005 inches (about 0.12mm), or slightly less than the average human hair.

Tens of thousands of wire recorders were produced and sold in the late 1940s and early ‘50s, along with almost a million miles of wire.  Such mass production, and the increasing availability of second-hand devices, swiftly brought the price down to a point where it became no longer purely a dictation machine for expensive offices, but a home-recording medium that people could, and did, use to record their own voices, as well as their own music and songs off the radio—thus giving the world its first example of illegal home recording.

Recovering Woody Guthrie’s only live recordings

This is how wire ended up as the audio format used for the only live recordings of the legendary protest singer Woody Guthrie, the Dylan of his day, whose 1949 performance at Rutgers University’s Fuld Hall was captured on wire by one Paul Braverman.

This recording, of the entire Guthrie concert, had been completely forgotten and was only rediscovered in 2001 when a couple of reels of wire were sent to the Woody Guthrie Archives. Unfortunately, back in those turn-of-the-century days of Internet infancy, working wire-recorder players were pretty hard to find in any condition, let alone working well. And 60-year-old wire recordings that have been played many hundreds of times are likely to be stretched or kinked in places or to have fallen victim to the usual metal fatigue and distortions introduced by wow and flutter.

So the gig recording was really in pretty bad shape; in places it was virtually a sonic assault with Guthrie sounding like, in the words of one listener, ”Charlie Brown’s school teacher” (i.e. completely unintelligible). But a team, informally led by Kevin M. Short, a mathematician at the University of New Hampshire, and audio engineer Jamie R. Howarth, decided that some kind of restoration would be possible and, using a customised tape deck, they cleverly used the background noise, and some creative maths, to perform the seemingly impossible.

Howarth came up with the notion that if they could just extract the bias signal, the pure tone beyond human hearing that all analogue recorders lay down, they could use it as a reference guide to help them remove the many degradation noises and speed variations. Unfortunately the team could find no bias signal at first—but a glimmer of hope emerged when they discovered a distant hum at 60Hz, a cross-feed from the electrical mains supply, which was enough to get them started.

After consulting with Patrick Wolfe, an electrical engineer at Harvard, they decided to use a bit of chaos theory and sample the sound—at thousands of times a second—at irregular rather than regular intervals (which, believe me, is not the normal way). Somehow it all worked and Woody Guthrie was heard live for the first time since the 1950s, and the team won a Grammy Award for Best Historical Album in 2008 with The Live Wire. Here’s the restored wire cut of Woody Guthrie’s Dead or Alive…

Dead or Alive

Other songs, although quite listenable, do undoubtedly show that there are limits to what can be done with some badly stored wire recordings.

Grand Coulee Dam

SEAC’s wire drives and cassettes.

A year after Woody’s live gig, the US National Bureau of Standards (now the National Institute of Standards and Technology) built the world’s third-ever stored-program computer (or the fourth, depending on who you believe), and this SEAC device actually used wire recorders to store digital data. With the newfangled computers using them, and appearances in movies like The Thing and Spy In The Sky, the wire recorder’s future seemed assured. But, as you can probably surmise, it was going to be downhill from there.

The long way down

By the mid 1950s, professional tape had become almost as durable as wire, and while sounding vastly better than its metal parent, it also had a much wider dynamic range. Tape now captured music almost in its full glory, whereas wire still tended to compress it half to death. The less complicated tape decks were also getting cheaper and soon became the recorder of choice for universities, schools, independent studios, and, eventually, home recordists who fancied stealing sounds from the radio.