Theme: "WHY, WHY?" you wonder. Let us consult the WISE MEN. I'll defer the complete explanation till we get to the unifier.
17 A. *Motown Records founder : BERRY GORDY. Yeah, I wanted BARRY. From back when Motown was a thing. You can read his interesting story here.
24. A *Cubs broadcaster known for singing along with "Take Me Out to the Ball Game" during the seventh-inning stretch : HARRY CARAY. Iconic baseball announcer. Hard to believe he's been gone for 17 years.
52 A. *"That'll Be the Day" singer : BUDDY HOLLY. Charles Hardin Holley, died in a plane crash in 1959.
Some bitter irony in these lyrics
3 D. *"The [52-Across] Story" Oscar nominee : GARY BUSEY.
Corrupting the very foundation of America
35 D. *"Football Night in America" analyst : TONY DUNGY. Also the very successful head coach of the Tampa Bay Buccaneers from 1996 to 2001, and the Indianapolis Colts from 2002 to 2008.
And the unifier: 39. Biblical trio ... and a homophonic hint to the answers to starred clues : WISE MEN. The Christian Bible does not name them, but they are traditionally considered to be Caspar, Balthazar, and Melchior. As you are probably aware, these names sound nothing like those in the theme fill, so we'll have to look in another direction for our homophone. Let's see -- what sounds like WISE? WhY are You looking at me that waY? AHA! That's it - the plural of the letter Y, the terminal letter for each theme guY's first and last name. Are these Y'S MEN noted for their wisdom, or are they just WISE guYs? You be the judge.
Hi gang, JazzBumpa here, not feeling particularly WISE with all the trouble I had sussing this theme. With 6 theme names and a unifier, this is extraordinarily thematically rich. Let's see how the rest of this puzzle rolls
1. Audio problem : LAG. AKA Latency. The time gap between responses in a remote live broadcast. Ideal is under 10 milliseconds.
4. Finish paying a bill, perhaps : LOG OFF. If you do your financial transactions on line.
10. Controlled : CALM. Not a common condition while watching sporting events.
14. Radio host Glass : IRA. This American Life on NPR.
15. Ethically indifferent : AMORAL. He just don't care.
16. Adidas rival : AVIA. Sports shoes.
19. Baptismal basin : FONT. To wash away sins.
20. Spanish royalty : REYES.
21. Oceanic reflux : EBB TIDE. Reflux threw me. Could this be the result of acid rain?
For slow close dancing
23. Jessica of "Dark Angel" : ALBA. She got her start on this TV show.
27. Mental grasp : UPTAKE.
29. McCain or McCaskill: Abbr. : SENator. Not a shared name this time, but a common title.
30. Tummy muscles : ABS. ABdominalS.
32. Circular gasket : O-RING
34. Time at the inn : STAY. Overnight, breakfast included.
38. Shad eggs : ROE. This presumed delicacy is the egg sack from an otherwise useless fish; and it is akin to a mouthful of fishy-tasting grit. It is only available in April at Joe Muir's and it's not on the menu. You have to ask for it. I made the mistake of doing that once.
42. Have a mortgage, e.g. : OWE. I OWE, I OWE, so off to work I go.
43. Send to the canvas : KAYO. Knock Out.
45. Graceful swimmers : SWANS.
46. Pull down : NET. Earn, so to speak. NET profits = revenues - expenses.
47. Dorm monitors, briefly : RA'S. Resident AssistantS.
50. Windpipe, e.g. : AIRWAY. Important step in CPR is to make sure the AIRWAY is clear.
56. Grand Forks locale: Abbr. : North DAKota.
59. "It's finally clear to me" : I SEE NOW. At last. Slow on the UPTAKE?
60. Accustom : INURE. I associate this with becoming accustomed to something unpleasant.
61. Sushi option : TUNA. Pick your fish
66. Follow, or follower : TAIL. To follow is to TAIL; the follower is a TAIL. If you pay someone to follow somebody again is that a retail RETAIL?
67. Listen to, as a podcast : TUNE IN.
68. Bearded beast : GNU.
69. Suburban street liners : ELMS. In those halcyon days of yore. Are there any left?
70. Physical jerks : SPASMS. Brief involuntary muscle contractions.
71. Blather : YAP. Running on at the mouth.
1. Heavenly scales : LIBRA. Astrology.
2. Spinning : AREEL. Clear enough, I guess, but in a brief search I couldn't find a definition or anything on usage.
4. Big name in chips : LAYS. Computers? Poker accessories?
5. Texter's "Unbelievable!" : O.M.G. Oh My Gosh/Golly/Goodness. Does that cover it?
6. Icky stuff : GOO. Oh my GOO? That can't be right.
7. Rink legend Bobby : ORR. One of hockey's all time greats.
8. Sound system control : FADER. A device for varying sound [or light] intensity.
9. Spacecraft data-collection passes : FLY BYs. A flight past a target point to gather information.
10. Lounging robes : CAFTANS.
11. To have, in Le Havre : AVOIR. All perps. French.
12. Lavin or Blair : LINDA. Here is where they share the name. A pair of actors. One was the eponymous ALICE of the TV series, and the other was the demon posses child in The Exorcist.
13. Swabby's chum : MATEY. Sea slang. Swabby's obese chum is a vast MATEY.
18. Gather : REAP. AS a harvest.
22. Abbr. in ancient dates : B.C.E. Before the Common Era. Our high school memories aren't that ancient.
24. Mata __ : HARI. "Margaretha Geertruida "Margreet" Zelle MacLeod (7 August 1876 – 15 October 1917), better known by the stage name Mata Hari, was a Frisian exotic dancer and courtesan who was convicted of being a spy and executed by firing squad in France under charges of espionage for Germany during World War I."
25. Words before and after "is still" in "As Time Goes By" : A KISS.
Sam Played It
26. Time extension? : RENEWAL. Extending a subscription to Time magazine.
28. Garage service : TOW.
30. Storied vessel : ARK. Noah's big boat.
31. Flapper's wrap : BOA. A decorative feathery scarf.
33. Google Apps component : G-MAIL.
36. Knock the socks off : AWE. O.M.G level impression.
37. Still : YET.
40. Professor 'iggins : 'ENRY. My Fair Lady.
41. Sydney is its cap. : NSW. New South Wales, Australia.
44. Tough times : ORDEALS. Things to become UNURED to.
48. Writer Rand : AYN. The Fountainhead, Atlas Shrugged.
49. Young pigs : SHOATS.
51. Latin word on a cornerstone : ANNO. The year of construction.
52. Please, in Potsdam : BITTE.
53. Same as always : USUAL.
54. Jeans material : DENIM. Blue pants fabric. And, a homophone clecho ---
63. Genes material : DNA. DeoxyriboNucleic Acid. The stuff of life.
55. Come clean : OWN UP. I couldn't suss this expression as a kid. I guess you need to own your actions.
57. Place for matches : ARENA. Sporting event venue.
58. Light a fire under : KEY UP.
60. Charged atoms : IONS.
64. "I'm listening" : YES. I'm all ears.
65. Grand Canyon viewing spot : RIM.
Well, that was a fine Wednesday with some great musical interludes. Now I hope you all know Y.