Bass-baritone Cedric Berry from Long Beach Opera records a segment in his living room during the outbreak of the coronavirus disease (COVID-19), in Los Angeles, California, U.S., May 27, 2020. REUTERS/Mario Anzuoni REFILE - CORRECTING VOICE RANGE

Bass-baritone Cedric Berry from Long Beach Opera records a segment in his living room during the outbreak of the coronavirus disease (COVID-19), in Los Angeles, California, U.S., May 27, 2020. REUTERS/Mario Anzuoni REFILE - CORRECTING VOICE RANGE

Baritone Davone Tines performs for honorary degree recipient Lonnie Bunch, incoming secretary of the Smithsonian Institution, during the 368th Commencement Exercises at Harvard University in Cambridge, Massachusetts, U.S., May 30, 2019. REUTERS/Brian Snyder

Tenor Yusif Eyvazov (L), director Riccardo Chailly (2L), soprano Anna Netrebko and baritone Luca Salsi acknowledge the applause of the audience at the end of "Andrea Chenier" at La Scala opera house downtown Milan, Italy December 7, 2017. REUTERS/Stefano Rellandini

People surround the coffin of Russian baritone Dmitri Hvorostovsky, who died at the age of 55 on November 22, during a ceremony of paying last respects to him outside Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

People pay last respects to Russian baritone Dmitri Hvorostovsky, who died at the age of 55 on November 22, during a ceremony outside Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

People pay last respects to Russian baritone Dmitri Hvorostovsky, who died at the age of 55 on November 22, during a ceremony outside Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

People surround the car carrying the coffin of Russian baritone Dmitri Hvorostovsky, who died at the age of 55 on November 22, during a ceremony of paying last respects to him outside Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

A portrait of Russian baritone Dmitri Hvorostovsky, who died at the age of 55 on November 22, is seen next to a driver during a ceremony of paying last respects to him at Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

Parents of Russian baritone Dmitri Hvorostovsky, Lydmila and Alexander attend a ceremony of paying last respects to their son, who died at the age of 55 on November 22, at Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

People pass a portrait of Russian baritone Dmitri Hvorostovsky, who died at the age of 55 on November 22, during a ceremony of paying last respects to him at Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

People queue to pay last respects to Russian baritone Dmitri Hvorostovsky, who died at the age of 55 on November 22, during a ceremony at Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

Widow of Russian baritone Dmitri Hvorostovsky, Florence (2nd L) with their children Maxim and Nina attend a ceremony of paying last respects to Hvorostovsky, who died at the age of 55 on November 22, at Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

People pay last respects to Russian baritone Dmitri Hvorostovsky, who died at the age of 55 on November 22, during a ceremony at Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

People pay last respects to Russian baritone Dmitri Hvorostovsky, who died at the age of 55 on November 22, during a ceremony at Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

People stand in front of a coffin with the body of Russian baritone Dmitri Hvorostovsky, who died at the age of 55 on November 22, at Tchaikovsky Concert Hall in Moscow, Russia November 27, 2017. REUTERS/Maxim Shemetov

Runner LaShawn Merritt poses for a portrait at the U.S. Olympic Committee Media Summit in Beverly Hills, Los Angeles, California March 8, 2016. "I donÕt really listen to music when I train," said Merritt. "When I grew up I was in a band, so I listened to jazz a lot to calm me down. I played the trumpet and the baritone for 8 years." REUTERS/Lucy Nicholson

Runner LaShawn Merritt poses for a portrait at the U.S. Olympic Committee Media Summit in Beverly Hills, Los Angeles, California March 8, 2016. "I don't really listen to music when I train," said Merritt. "When I grew up I was in a band, so I listened to jazz a lot to calm me down. I played the trumpet and the baritone for 8 years." REUTERS/Lucy Nicholson

Runner LaShawn Merritt poses for a portrait at the U.S. Olympic Committee Media Summit in Beverly Hills, Los Angeles, California March 8, 2016. "I don't really listen to music when i train," said Merritt. "When I grew up I was in a band, so I listened to jazz a lot to calm me down. I played the trumpet and the baritone for 8 years." REUTERS/Lucy Nicholson

Runner LaShawn Merritt poses for a portrait at the U.S. Olympic Committee Media Summit in Beverly Hills, Los Angeles, California March 8, 2016. "I don't really listen to music when i train," said Merritt. "When I grew up I was in a band, so i listened to jazz a lot to calm me down. I played the trumpet and the baritone for 8 years." REUTERS/Lucy Nicholson

Italian baritone Enrico Maria Marabelli (L) and soprano Alla Vasilevitsky perform during a dress rehearsal for Carmina Burana by Carl Orff ahead of the Israeli Opera Festival, which begins Thursday, at Masada June 3, 2015. Carl Orff's Carmina Burana, composed in the Nazi era, will be showcased at the Israeli opera festival against the backdrop of a towering desert plateau that stands as a symbol of Jewish resistance and sacrifice. Picture taken June 3, 2015. REUTERS/Ammar Awad

Italian baritone Enrico Maria Marabelli performs during a dress rehearsal for Carmina Burana by Carl Orff ahead of the Israeli Opera Festival, which begins Thursday, at Masada June 3, 2015. Orff's Carl Orff's Carmina Burana, composed in the Nazi era, will be showcased at the Israeli opera festival against the backdrop of a towering desert plateau that stands as a symbol of Jewish resistance and sacrifice. Picture taken June 3, 2015. REUTERS/Ammar Awad

Italian baritone Enrico Maria Marabelli (L) and countertenor Alon Harari perform during a dress rehearsal for Carmina Burana by Carl Orff ahead of the Israeli Opera Festival, which begins Thursday, at Masada June 3, 2015. Carl Orff's Carmina Burana, composed in the Nazi era, will be showcased at the Israeli opera festival against the backdrop of a towering desert plateau that stands as a symbol of Jewish resistance and sacrifice. Picture taken June 3, 2015. REUTERS/Ammar Awad

U.S. baritone Lee Poulis performs during a rehearsal of "Doctor Atomic" opera by John Adams at the Maestranza theatre in the Andalusian capital of Seville March 10, 2015. The opera will run on March 13, 16 and 18. Picture taken March 10, 2015. REUTERS/Marcelo del Pozo (SPAIN - Tags: ENTERTAINMENT SOCIETY)

U.S. baritone Lee Poulis (C) and baritone Jouni Kokora (L) of Finland and baritone Benat Egiarte of Spain perform during a rehearsal of "Doctor Atomic" opera by John Adams at the Maestranza theatre in the Andalusian capital of Seville March 10, 2015. The opera will run on March 13, 16 and 18. Picture taken March 10, 2015. REUTERS/Marcelo del Pozo (SPAIN - Tags: ENTERTAINMENT SOCIETY)

U.S. baritone Lee Poulis (L) and baritone Jouni Kokora of Finland perform during a rehearsal of "Doctor Atomic" opera by John Adams at the Maestranza theatre in the Andalusian capital of Seville March 10, 2015. The opera will run on March 13, 16 and 18. Picture taken March 10, 2015. REUTERS/Marcelo del Pozo (SPAIN - Tags: ENTERTAINMENT SOCIETY)

U.S. baritone Lee Poulis (C) and baritone Jouni Kokora (L) of Finland perform during a rehearsal of "Doctor Atomic" opera by John Adams at the Maestranza theatre in the Andalusian capital of Seville March 10, 2015. The opera will run on March 13, 16 and 18. Picture taken March 10, 2015. REUTERS/Marcelo del Pozo (SPAIN - Tags: ENTERTAINMENT SOCIETY)

U.S. baritone Lee Poulis (R) and baritone Jouni Kokora of Finland perform during a rehearsal of "Doctor Atomic" opera by John Adams at the Maestranza theatre in the Andalusian capital of Seville March 10, 2015. The opera will run on March 13, 16 and 18. Picture taken March 10, 2015. REUTERS/Marcelo del Pozo (SPAIN - Tags: ENTERTAINMENT SOCIETY TPX IMAGES OF THE DAY)

U.S. baritone Lee Poulis performs during a rehearsal of "Doctor Atomic" opera by John Adams at the Maestranza theatre in the Andalusian capital of Seville March 10, 2015. The opera will run on March 13, 16 and 18. Picture taken March 10, 2015. REUTERS/Marcelo del Pozo (SPAIN - Tags: ENTERTAINMENT SOCIETY)

Baritone Scott Taylor (L) and soprano Maria Ferrante (R), along with the "Microbe Choir," perform the mini-opera "What's Eating You" during the 24th First Annual Ig Nobel Prizes awards ceremony at Harvard University in Cambridge, Massachusetts September 18, 2014. The annual prizes, meant to entertain and encourage global research and innovation, are awarded by the Annals of Improbable Research as a whimsical counterpoint to the Nobel Prizes which will be announced next month. REUTERS/Brian Snyder (UNITED STATES - Tags: SCIENCE TECHNOLOGY EDUCATION SOCIETY)

American tenor Tom Randle (Jack Twist) (L), and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), perform during a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014 REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), are silhouetted inside a tent as they perform during a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014 REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) (L), and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), perform during a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014 REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) (R), and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), pose with a backdrop of Madrid prior to a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014. REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) (L), and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), pose with a backdrop of Madrid prior to a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014. REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) (L), and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), pose before a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014. REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) front, and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), perform during a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014. REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) (R), and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), perform during a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014 REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) front, and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), perform during a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014. REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) (R), and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), pose with a backdrop of Madrid prior to a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014. REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) front, and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), perform during a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014. REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) front, and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), perform during a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014. REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) (L), and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), perform during a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014. REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) front, and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), perform during a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014. REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

American tenor Tom Randle (Jack Twist) front, and Canadian bass-baritone Daniel Okulitch (Ennis del Mar), perform during a dress rehearsal of the opera "Brokeback Mountain" at the Teatro Real in Madrid, January 24, 2014. When Annie Proulx first published Brokeback Mountain in the New Yorker in 1997, the American writer said she did not suspect the tragic cowboy love story would go on to inspire an Oscar-winning film and even an opera. The doomed romance between two Wyoming sheep herders caught the eye of American composer Charles Wuorinen for its potential as an opera, now set for its global debut in Madrid on Tuesday. Picture taken January 24, 2014. REUTERS/Paul Hanna (SPAIN - Tags: ENTERTAINMENT SOCIETY)

Tenor Martin Kelly (L) as George Blonsky, soprano Maria Ferrante (C) as Charlotte Blonsky, and baritone Philip Lima, as the Zookeeper, perform the mini-opera "The Blonsky Device" during the 23rd First Annual Ig Nobel Prize ceremony at Harvard University in Cambridge, Massachusetts September 12, 2013. The annual prizes, meant to entertain and encourage global research and innovation, are awarded by the Annals of Improbable Research as a whimsical counterpart to the Nobel Prizes which will be announced next month. REUTERS/Brian Snyder (UNITED STATES - Tags: SOCIETY SCIENCE TECHNOLOGY ENTERTAINMENT)

A woman practises playing her baritone horn on Havana's El Malecon seafront boulevard March 22, 2013. The "bombardino" or baritone horn is a wind instrument that produces a sound similar to that of the clarinet, but resembles a type of French horn used mainly for playing "danzon" or salsa music popular in Cuba. REUTERS/Desmond Boylan (CUBA - Tags: SOCIETY)

A woman practises playing her baritone horn on Havana's El Malecon seafront boulevard March 22, 2013. The "bombardino" or baritone horn is a wind instrument that produces a sound similar to that of the clarinet, but resembles a type of French horn used mainly for playing "danzon" or salsa music popular in Cuba. REUTERS/Desmond Boylan (CUBA - Tags: SOCIETY)

Britain's Kristan Bromley competes in the men's skeleton race during the FIBT Bobsleigh and Skeleton World Cup competition in Altenberg January 6, 2012. REUTERS/David W Cerny (GERMANY - Tags: SPORT BOBSLEIGH)

Ju Min-jeong, a 17-year-old high school student, dances during the final round of "Korea's Got Talent" in Seoul August 21, 2011. Ju defeated her powerful baritone competitor Sung-Bong Choi, South Korea's manual worker-turned-international singing sensation, in the final round of the TV audition show. Ju has already been branded "Poppin' Dance Empress" among her fan groups here. REUTERS/Jo Yong-Hak (SOUTH KOREA - Tags: ENTERTAINMENT)

Ju Min-jeong, a 17-year-old high school student, dances during the final round of "Korea's Got Talent" in Seoul August 21, 2011. Ju defeated her powerful baritone competitor Sung-Bong Choi, South Korea's manual worker-turned-international singing sensation, in the final round of the TV audition show. Ju has already been branded "Poppin' Dance Empress" among her fan groups here. REUTERS/Jo Yong-Hak (SOUTH KOREA - Tags: ENTERTAINMENT)

Sung-bong Choi, 22, sings during a final round of "Korea's Got Talent" in Seoul August 21, 2011. Choi's powerful baritone and his inspirational life story have now pulled at the heart strings of millions around the world thanks to the Internet, a story rivalling that of Susan Boyle. Choi now has as many fans from outside South Korea as at home and has been lauded by the likes of Justin Bieber. Choi won the second place at the final. To match KOREA-TALENT/ REUTERS/Jo Yong-Hak (SOUTH KOREA - Tags: ENTERTAINMENT SOCIETY)

Sung-bong Choi, 22, sings during a final round of "Korea's Got Talent" in Seoul August 21, 2011. Choi's powerful baritone and his inspirational life story have now pulled at the heart strings of millions around the world thanks to the Internet, a story rivalling that of Susan Boyle. Choi now has as many fans from outside South Korea as at home and has been lauded by the likes of Justin Bieber. Choi won the second place at the final. To match KOREA-TALENT/ REUTERS/Jo Yong-Hak (SOUTH KOREA - Tags: ENTERTAINMENT SOCIETY)

Sung-bong Choi, 22, sings during a final round of "Korea's Got Talent" in Seoul August 21, 2011. Choi's powerful baritone and his inspirational life story have now pulled at the heart strings of millions around the world thanks to the Internet, a story rivalling that of Susan Boyle. Choi now has as many fans from outside South Korea as at home and has been lauded by the likes of Justin Bieber. Choi won the second place at the final. To match KOREA-TALENT/ REUTERS/Jo Yong-Hak (SOUTH KOREA - Tags: ENTERTAINMENT SOCIETY)

Russian soprano Anna Netrebko (L) and Uruguayan bass-baritone Erwin Schrott listen to German tenor Jonas Kaufmann (not pictured) during a concert at the Waldbuehne in Berlin August 16, 2011. REUTERS/Tobias Schwarz (GERMANY - Tags: ENTERTAINMENT SOCIETY)

Uruguayan bass-baritone Erwin Schrott (R) and Russian soprano Anna Netrebko acknowledge the audience during a concert at the Waldbuehne in Berlin August 16, 2011. REUTERS/Tobias Schwarz (GERMANY - Tags: ENTERTAINMENT SOCIETY)

Uruguayan bass-baritone Erwin Schrott (L-R), Russian soprano Anna Netrebko and German tenor Jonas Kaufmann acknowledge the audience during a concert at the Waldbuehne in Berlin August 16, 2011. REUTERS/Tobias Schwarz (GERMANY - Tags: ENTERTAINMENT SOCIETY)

Uruguayan bass-baritone Erwin Schrott (L) and Russian soprano Anna Netrebko acknowledge the audience during a concert at the Waldbuehne in Berlin August 16, 2011. REUTERS/Tobias Schwarz (GERMANY - Tags: ENTERTAINMENT SOCIETY)

Russian soprano Anna Netrebko (L) hands over a glass to Uruguayan bass-baritone Erwin Schrott after a concert at the Waldbuehne in Berlin August 16, 2011. REUTERS/Tobias Schwarz (GERMANY - Tags: ENTERTAINMENT SOCIETY)

Uruguayan bass-baritone Erwin Schrott (R) and Russian soprano Anna Netrebko acknowledge the audience during a concert at the Waldbuehne in Berlin August 16, 2011. REUTERS/Tobias Schwarz (GERMANY - Tags: ENTERTAINMENT)