“Solo” sounds like “so low.”
 
“Perhaps I may more properly say, my hearers, that each of these stars sing a solo—so low (as my respected friend John Gossin would say,) that you can’t hear it” was printed in the Gallipolis (OH) Journal on January 8, 1852. “Jones says that his wife has a lovely voice for a church choir or a musicale, but at home he prefers her to sing ‘solo,’ that is so low, at his intervals of rest, that he can’t hear her” was printed in The True Democrat (Bayou Sara, LA) on September 3, 1892. The joke is still told.
   
“They asked if I could sing tenor—ten or twelve miles away” is a similar joke.
 
   
8 January 1852, Gallipolis (OH) Journal,  “New Series” by Dow Jr., pg. 4, col. 2:
Perhaps I may more properly say, my hearers, that each of these stars sing a solo—so low (as my respected friend John Gossin would say,) that you can’t hear it.
   
3 September 1892, The True Democrat (Bayou Sara, LA), “Short Cuts,” pg. 2, col. 2:   
Jones says that his wife has a lovely voice for a church choir or a musicale, but at home he prefers her to sing “solo,” that is so low, at his intervals of rest, that he can’t hear her.
 
15 October 1938,

(Jersey City, NJ), “About Town,” pg. 9, col. 3:
Overheard:
FRANK: “Sing solo, CLIFF.”
CLIFF: “Solo?”
FRANK: “Yea, so low I can’t hear you!!!!”
 
1 November 1957, Bennington (VT) Evening Banner, pg. 3, col. 5 ad:
Modern Proverbs
(...)
11. YES, DO SING A SOLO.
(So low we can’t hear you.)
(Greg Cullinan insurance and real estate.—ed)
 
3 June 1965, Star-Gazette and Advertiser (Elmira, NY), “Looking Around” by Ed Telley, pg. 19, col. 1:
A woman, auditioning for a part in a musical, sang badly off key. After finishing the song, she asked the director if she could sing a solo.
 
“I wish you would,” he muttered so she couldn’t hear. “So low, I can’t hear you.”
 
Google Books   
June 1988, Boys’ Life, “Think & Grin,” pg. 66:
Stilt: How about singing solo?
Pee Wee: Really? You want me to sing solo!
Stilt: Yeah, so low the rest of us won’t hear you.-John Cumings, Windham, N.H.
 
2 December 1990, The Journal-News (Nyack, NY), “Just for Laughs,” Pennywhistle Press, pg. 3, col. 2:
Tom: I wish you’d sing solo.
Laura: Solo?
Tom: So low I couldn’t hear you!
Laura: Not funny! Have you ever heard yourself sing? You should sing tenor.
Tom: Tenor?
Laura: Tenor twelve miles away!
Loren Williams Age 8
Jessica Williams Age 10
Satellite Beach, Florida
       
Google Groups: rec.humor
musician jokes    
Fulton Richard
8/1/95
(...)
I’ve been asked to sing solo, so low that no one can hear me!
 
Google Books
Ventriloquism Made Easy
By Kolby King
Mineola, NY: Dover Publications
1997
Pg. 21:
V: So you don’t want me to sing?
F: Don’t get me wrong. I love for you to sing solo.
V: You love for me to sing solo?!
F: Sure. So low l can’t hear you
     
Google Groups: alt.humor.puns
Music Puns
Steve P.
6/26/97
Shelley has no wife! She’s solo!
And you should hear her sing. Ugh!    😊
I wish she’d sing SOLO. So low that we can’t hear her! 
 
Twitter
Magnum
@VideosMagnum
I asked a friend of mine to sing solo (So low no one could hear him.)
1:20 AM · Apr 13, 2009·Twitter Web Client
 
Twitter
Curley Q. Link 🌊⚖️🗽🇺🇸✌🏻 #BLM #SaveDemocracy
@curly_woowoowoo
Nice!!!!!!!  Not too bad a voice!
But, can you sing Tenor?
Ten or twelve miles away! (JK)
Or
Solo?
So low we can’t hear you?
🤣😂👊🏻✌🏻
Really, not bad! 👏🏻👏🏻🤷‍♂️🎼
Quote Tweet
Howard
@HowardA_Esq
· Jun 2
I didn’t want to do it, really, but with his incessant whining I had no choice. So yes, I cannot sing, but enjoy and laugh at his and my expense.
0:45
5:13 AM · Jun 3, 2019·Twitter for iPad
 
Twitter
ChefDad
@Chefdad2000
Replying to
@AgdaCoroner
Can ya sing solo?
So low we can’t hear you.
11:37 PM · Aug 4, 2019·Twitter for iPad
 
Reddit—Dadjokes
Posted by u/SpaghettiSquawk August 5, 2019
You know, I’m such a good singer, people always ask me to sing solo
......solo they can’t hear me.
Coincidentally, they also ask me to sing tenor.
.....tenor twelve miles away.