CHICAGO – Between his first Grateful Dead show in 1988, at age 15, and the death of Jerry Garcia in 1995, William Walker saw the band about 130 times, a modest number in the Deadhead universe. But Walker has experienced many, many more of the band’s concerts through his passion for live audience taping, collecting thousands of cassettes and terabytes-worth of digital audio, while also contributing his own recordings to the seemingly endless archive.

So when he scored passes this year to be one of the few fans allowed to record the final shows at Soldier Field, culminating Sunday, "I completely freaked out all the animals in my house – jumping, screaming and running around," Walker said of his two dogs and two cats.

A proud member of the increasingly obsolete jam-band fan contingent known as "tapers," Walker drove 900 miles from New Orleans armed with equipment he would lug from show to show – an intricate rig he estimated to be worth least $8,500, including furry microphones, a hydra-headed stand, tangles of wires, a Tascam digital recorder and a plastic protractor straight out of a high school geometry class. One custom-made cable alone cost him $400.

Although there would be fewer than three dozen approved bootleggers in what’s known as the tapers’ section each night in a crowd of more than 70,000, it wouldn’t be a Dead show without them. Not content to relive the performances via the on-demand, high-quality video streams available immediately, the concert replays from local and satellite radio, or the band’s own commemorative 12-CD, seven-DVD box set, scheduled for release this fall, tapers like Walker still – in 2015 – insist on doing it themselves, for reasons both practical and traditional.

"This is the last big taper section," Walker, whose digital recordings are typically available online within hours of the encore, said of the Dead’s "Fare Thee Well" 50th anniversary shows. "It’s legitimately the end of an era."

Introduced to taper culture by his older cousins, Walker, 42, sees his continued dedication as a carrying of the torch for previous generations of Deadheads. Despite taping at so many shows that he has lost count, "I still consider myself a novice – an up-and-comer," he said, estimating that most of the remaining tapers (the vast majority of whom are men) are in their 50s or 60s.

Officially approved for noncommercial recording by the Grateful Dead since the early 1980s, tapers are a subculture within a subculture – spreaders of audio sacrament among a famously evangelical following. While the band never matched the record sales of its classic-rock peers, the Dead thrived as a freewheeling live act thanks in part to a word-of-mouth trade network of concert recordings, a system it passed down to its spiritual children such as Phish and Widespread Panic.

"The band was very farsighted – it reified an informal practice that had been going for many years," said David Gans, the host of "The Grateful Dead Hour," a nationally syndicated radio show. "In time, it proved to be one of the most efficient marketing mechanisms."

Authorizing the tapers and giving them their own section in the crowd had a less business-minded rationale, too, said Dennis McNally, the band’s former spokesman and the author of "A Long Strange Trip: The Inside History of the Grateful Dead."

"To stop it would require security measures so draconian that it would ruin the ambience of the show," and the Dead "hated being cops," he said. Corralling tapers behind the soundboard, where they remain today, allowed the band’s longtime audio engineer, Dan Healy, as well the audience, to see the stage instead of being blocked by microphone stands, he added.

David Lemieux, the Dead’s official archivist, was a hard-core taper between 1989 and 1991. "I did it specifically because I had no patience," he said. "I wanted to walk out of that show and drive back to my hotel listening to what I’d just seen."

"There was nothing more thrilling than getting two or three padded envelopes in the mail every day," he said, recalling the camaraderie he felt with strangers as they created copies of their favorite shows to share. "We would plan our days around 46-minute intervals" – the length of one cassette side – "so you could be back to flip the tape. I remember sleeping and setting alarms every 45 minutes."

Even as its necessity has faded, with bands like Phish offering a free MP3 download of every show to attendees straight from the venue’s soundboard, the seemingly archaic hobby has thrived thanks to technological advances. Most tapers switched to digital recording in the ’90s – although there was at least one analog holdout at Soldier Field, Walker said – and sites like etree.org, taperssection.com and the Live Music Archive, part of the archive.org, offer meticulously organized, easily downloadable databases.

Alex Whitney, a Deadhead with taper tickets to all five farewell shows, including those in late June in Santa Clara, said tapers are similar to wine connoisseurs: "They know the vineyard, they know the grapes, they know the farmer, they know the vendor," he said. "Deadheads who are uploading stuff to archive.org are including every tape deck, every cable, every microphone, every preamplifier."

Whitney added that while the Dead’s studio albums are "decent enough, they don’t really capture the sound quality of the live experience."

It’s all about the ambience, Walker concurred: "There are some recordings of shows where you can almost feel how hot the room was. That just doesn’t transfer to a soundboard recording."

Yet he knows it’s a dying art. "It’s built on this culture of sharing," he said of taping. "Younger people don’t really understand the effort that people put into it and that’s a bummer."

When his sister graduated from college, Walker gifted her about 4,000 hours of live music, including Phish and the Dead, on tape – "a significant portion of my analog collection," he said. The rest of his cassettes were destroyed in Hurricane Katrina. But he is committed to carrying taping through the digital age, even helping to spread "the entire opus" of the Grateful Dead online – more than 10,000 recordings, including multiple sources for some shows, across 12 terabytes of data.

Of having his own microphones at the farewell shows, Walker said, "I don’t want to sound sappy, but this is the closing chapter to a part of my life."

© 2015 The New York Times Company