I’m not sure why, but I keep hearing parallels between folk rock “classics” and mid-’70s R&R of the sort practiced by journeymen such as, oh, Blue Oyster Cult, whose 1976 hit “(Don’t Fear) the Reaper” was both praised and derided for channeling ethereal Byrds-like harmonies in the service of a song that seems to endorse a suicide pact.

“Reaper” ensured BOC a permanent berth on the 20th-century pop culture sunset cruise, though it’s regrettable such a majestic composition is trotted out every Halloween like a plastic treak-or-treat pumpkin; far more instructive is to listen to “Reaper” back to back with the song many assume inspired it: the Byrds’ “Eight Miles High.”

No jingle-jangle mornings here—”Eight Miles” is struck in a doomy minor key (familiar territory for BOC) and explodes with Roger McGuinn’s freaked-out interpretation of a John Coltrane sax solo. By contrast, “Reaper” is actually more Byrds-like, at least until the bridge and a paint-peeling guitar solo by Donald “Buck Dharma” Roeser, who wrote the song and sang lead.

Mash ‘em up or just drop “Reaper” into your Byrds mix to remind yourself of the long, long shadow cast by the canyon’s original folk-rockers.

Here we have three songs in the great mid-70s thunder-metal tradition that share all sorts of antecedents—except that Aussie wunderkinder Wolfmother’s savage “Dimension” is farmstand fresh, released in 2006, while late lamented Who bassist John Entwistle’s “My Size” and Mountain’s imdomitable “Mississippi Queen” hail from 1971 and ‘70, respectively.

The Entwistle track—by far the heaviest on this tragically overlooked album, now re-mastered and re-released with a slew of outstanding outtakes (including a go at Neil Young’s “Cinnamon Girl”)—has the killer crunch guitar-’n-bass riff pioneered by the portly guitarist Leslie West on “Mississippi Queen,” which launched a thousand lesser blooze-rock permutations throughout the early ’70s at “concerts” at choice venues like Chicago’s Aragon Ballroom, whose nickname when I frequented it was “Quaalude Alley.” Nice.

Wolfmother seems to have imbibed it all irony-free on their caterwauling hit which is a fittting turnabout; after a brief honeymoon with the rock press, Mountain was savaged as irredeemable sludge even though the music was taught, proud and unapologetic—qualities that make it suitable for reframing 30-odd years later by punks like Wolfmother.

Dave Brubeck’s classic “Take Five” and Traffic’s “Low Spark of High-Heeled Boys” sound pretty great back to back as both are built around charismatic piano riffs and tricky time-keeping.

Brubeck’s composition is often credited with bringing the 5/4 time signature—that is, five beats per measure, each quarter note having the value of one beat—to the masses.

Much rock and roll is famously in 4/4 or “standard” time—or jacked up, as immortalized by Chuck Berry in “Roll Over Beethoven” (”…rockin’ in two-by-two”), in so-called cut or half time.

But from the mid-’60s on the new generation of rock performers, influenced by jazz greats like Miles Davis and John Coltrane (David Crosby) and avant-garde composers like Edgar Varise (Frank Zappa), started building compositions around unconventional, for pop and rock, time signatures.

The Buffalo Springfield’s “Expecting to Fly,” to cite an early example, weaves unnervingly between 4/4 and 3/4 (waltz) time. Led Zeppelin, witlessly derided by the first generation of Rolling Stone critics as artless barbarians, wrote and arranged many of their songs around jarring time signatures thanks to the enormous talents of Jimmy Page and drummer John Bonham. Examples include the lead-in to the climactic guitar solo in “Stairway to Heaven,” the entirety of “Four Sticks (in 5/8) and “The Ocean,” which careens between 15/8 and 4/4. (For further discussion, see this fascinating thread.)

Getting back to “Low Spark,” the consensus seems to be that it’s actually in 4/4 but is jerked around so relentlessly by syncopations and polyrhythms (those hands clapping in double time, for example) that you’d never know it.

Two favorite tracks from two bands that hit their stride in the mid-90s on opposite ends of the planet and aesthetic spectrum.

First up, Rocket from the Crypt’s “Little Arm” from the band that defined San Diego’s invigorating post-punk rock scene centered around the tiny Casbah club.

Rocketeer John Reis sings through what is probably an Astatic harmonica microphone—a vogue shared by the Breeders on their hit “Cannonball”—on this uncharacteristically downtempo composition (its title perhaps a smirking nod to Hendrix’s “Little Wing.”)  Great song from band’s breakthrough Circa: Now! album, frantic and still fresh 15 years after its release. (RFTC packed it in Halloween night last year at a sold-out farewell show in their hometown.)

Next, “How Do” from Sneaker Pimps’ Becoming X, noteworthy for the hit “Six Underground” and this wistful contemplation featuring singer Kelli Dayton’s vocal. Dayton was dismissed after Becoming X as the technopop outfit’s founding members Chris Corner and Liam Howe apparently feared Dayton’s babydoll voice pigeonholed the act.

Anyway, the songs sound great back to back or maybe even truly mashed up; snip off the spoken-word intro to “How Do” for a more effective cross-fade.

Stumbled upon this one via the shuffle feature in iTunes.

Cheap Trick’s “Takin’ Me Back,” from the band’s shimmering third album “Heaven Tonight,” opens with more or less the identical guitar riff as “Mainline Florida,” from Eric Clapton’s “comeback” album 461 Ocean Boulevard.

They sound great back to back; start with the CT song, one of guitarist Rick Nielsen’s prettier contemplative mid-tempo rockers, which opens and closes with the “Mainline Florida” riff—same key, just half the tempo as Clapton’s.

Great crossfade; your friends will think you’re a genius. Or something.

Ted Nugent and the Beasties?

Terrible Ted’s 1975 debut album after years of thrashing through the Midwestern ballroom circuit with increasingly threadbare versions of the Amboy Dukes had its share of hokum, but it did include the magnficent (and magnificently sexist) droning jam “Stranglehold.”

The Beastie Boys’ “Sabotage” with its beloved video of the boys careening Starsky & Hutch-style around Los Angeles, from the 1994 album Ill Communication, is based on a similar droning guitar riff and is likewise addictive. Contrast the Boys’ trademark caterwauling with that of Ted’s great singer, Derek St. Holmes.

Cue ‘em up and crank it, it’s Friday fer Chrissakes.

French electro-pop-ironists Air and ’60s easy-listeners the Association would seem to share only an alliterative vowel between them on these hits.

But check out the wistful Fafisa organ coda to 1967’s “Never My Love,” then Air’s near-homage in the oh-so-retro Moog break on “Sexy Boy,” released in 1998.

It’s been pointed out the Association were a more than credible rock n’ folk outfit who got caught up in the grinding pop-cultural gears of the late ’60s, when their string of lush AM radio hits such as “Cherish” and “Windy” suddenly became a liability.

The band actually opened 1967’s landmark Monterey Pop Festival (when the Beach Boys, who were wrestling with relevance problems at their own at the time, backed out at the last minute) but the Association’s appeal was too frankly mainstream to save them in the post-Monterey youthquake.

Air has made a fetish out of gentrifying pop ciphers from the early ’80s and beyond on hits like “Cassanova 70″ and “Sexy Boy” and blending them anew with electronica and a continental pop sensibility that somehow recalls an apres-ski lounge in Chamonix around 1967.

So it’s really no surprise that an echo of one of the ’60s’ great pop records might reverberate reverentially on of their stronger compositions.

Today, we compare n’ contrast J.J. Cale’s “Travelin’ Light” from his landmark 1977 album Troubadour and “Miss Jones” by Atlanta hip-hop duo Rehab, from the Southern Discomfort album.

“Miss Jones’s” liquid rhythm guitar accompaniment is clearly an homage to Cale’s effortless grooves which gave the world “After Midnight” and “Cocaine” courtesy of Eric Clapton’s gargantuan cover hits.

“Travelin’ Light” sports Cale’s typically light touch on guitar and minimal, metaphorical lyrics (”travelin’ light/is the only way to fly”); “Miss Jones” floats along on its Cale-inspired guitar line while Danny Alexander and Jason “Brooks” Buford get explicit (lusting after a girl whom Miss Jones “be keeping in a cage” so as not to “get laid by the B-boys”) sweetened by their comfortably Southern smarts.

Tempos are about the same though the songs are in completely different keys. Toss them back to back on a playlist and watch your party jump.

Who’d have thought there could be a connection between flower-of-England ’60s pop queen Petula Clark’s “Don’t Sleep in the Subway” and 1970s Dutch prog-rock titans Focus’s “Focus 3.”

Well, there could. I’m a little nonplussed it occurred to me, but it did.

Anyway, after side-by-side comparison, there’s no question that the build to the chorus to both songs is essentially identical.

Whereas Petula sings: “I’ve heard it all a million times before; take off your coat, my love, and close the door” Focus’s ace guitarist Jan Akkerman plays a majestic ringing guitar line that traces essentially the same melody.

The similarity ends there, as “Focus 3″ transitions to a beautifully integrated chorus while “Subway” abruptly shifts styles, almost as if starting a different song. Which, it turns out, it more or less does.

Apparently,”Subway” writer Tony Hatch stitched the song together from fragments of three uncompleted songs, which would account for the jarring juxtaposition of the grandiloquent build to the chorus and the twinky chorus itself.

Anyway, enough—that’s more than even I can tolerate on this ridiculous subject.