1 00:00:07,249 --> 00:00:09,249 Gripped with vengeful passion, 2 00:00:09,249 --> 00:00:11,859 The Queen of the Night tears across the stage. 3 00:00:11,859 --> 00:00:14,249 She begins to sing her titular aria, 4 00:00:14,249 --> 00:00:19,470 one of the most famous sections from Mozart’s beloved opera, The Magic Flute. 5 00:00:19,470 --> 00:00:21,890 The orchestra fills the hall with music, 6 00:00:21,890 --> 00:00:25,460 but the queen’s voice soars above the instruments. 7 00:00:25,460 --> 00:00:28,700 Its melody rings out across thousands of patrons, 8 00:00:28,700 --> 00:00:34,296 reaching seats 40 meters away— all without any assistance from a microphone. 9 00:00:34,296 --> 00:00:38,116 How is it possible that this single voice can be heard so clearly, 10 00:00:38,116 --> 00:00:40,976 above the strains of dozens of instruments? 11 00:00:40,976 --> 00:00:44,176 The answer lies in the physics of the human voice, 12 00:00:44,176 --> 00:00:48,558 and the carefully honed technique of an expert opera singer. 13 00:00:48,558 --> 00:00:51,898 All the music in this opera house originates from the vibrations 14 00:00:51,898 --> 00:00:53,458 created by instruments— 15 00:00:53,458 --> 00:00:57,615 whether it’s the strings of a violin or the vocal folds of a performer. 16 00:00:57,615 --> 00:01:02,746 These vibrations send waves into the air, which our brains interpret as sound. 17 00:01:02,746 --> 00:01:04,706 The frequency of these vibrations–– 18 00:01:04,706 --> 00:01:07,886 specifically, the number of waves per second–– 19 00:01:07,886 --> 00:01:11,386 is how our brains determine the pitch of a single note. 20 00:01:11,386 --> 00:01:13,686 But in fact, every note we hear 21 00:01:13,686 --> 00:01:17,336 is actually a combination of multiple vibrations. 22 00:01:17,336 --> 00:01:21,336 Imagine a guitar string vibrating at its lowest frequency. 23 00:01:21,336 --> 00:01:22,946 This is called the fundamental, 24 00:01:22,946 --> 00:01:27,472 and this low pitch is what our ears mostly use to identify a note. 25 00:01:27,472 --> 00:01:32,434 But this lowest vibration triggers additional frequencies called overtones, 26 00:01:32,434 --> 00:01:35,574 which layer on top of the fundamental. 27 00:01:35,574 --> 00:01:41,074 These overtones break down into specific frequencies called harmonics, or partials– 28 00:01:41,074 --> 00:01:45,999 and manipulating them is how opera singers work their magic. 29 00:01:45,999 --> 00:01:50,323 Every note has a set of frequencies that comprise its harmonic series. 30 00:01:50,323 --> 00:01:55,075 The first partial vibrates at twice the frequency of the fundamental. 31 00:01:55,075 --> 00:01:59,728 The next partial is three times the fundamental’s frequency, and so on. 32 00:01:59,728 --> 00:02:03,608 Virtually all acoustic instruments produce harmonic series, 33 00:02:03,608 --> 00:02:08,478 but each instrument’s shape and material changes the balance of its harmonics. 34 00:02:08,478 --> 00:02:15,484 For example, a flute emphasizes the first few partials, 35 00:02:15,484 --> 00:02:17,614 but in a clarinet’s lowest register, 36 00:02:17,614 --> 00:02:21,344 the odd-numbered partials resonate most strongly. 37 00:02:21,344 --> 00:02:23,064 The strength of various partials 38 00:02:23,064 --> 00:02:27,064 is part of what gives each instrument its unique sonic signature. 39 00:02:27,064 --> 00:02:31,217 It also affects an instrument’s ability to stand out in a crowd, 40 00:02:31,217 --> 00:02:36,647 because our ears are more strongly attuned to some frequencies than others. 41 00:02:36,647 --> 00:02:40,947 This is the key to an opera singer’s power of projection. 42 00:02:40,947 --> 00:02:44,797 An operatic soprano—the highest of the four standard voice parts— 43 00:02:44,797 --> 00:02:47,627 can produce notes with fundamental frequencies 44 00:02:47,627 --> 00:02:53,047 ranging from 250 to 1,500 vibrations per second. 45 00:02:53,047 --> 00:02:55,737 Human ears are most sensitive to frequencies 46 00:02:55,737 --> 00:02:59,737 between 2,000 and 5,000 vibrations per second. 47 00:02:59,737 --> 00:03:03,657 So if the singer can bring out the partials in this range, 48 00:03:03,657 --> 00:03:08,497 she can target a sensory sweet spot where she’s most likely to be heard. 49 00:03:08,497 --> 00:03:10,817 Higher partials are also advantageous 50 00:03:10,817 --> 00:03:13,537 because there’s less competition from the orchestra, 51 00:03:13,537 --> 00:03:16,817 whose overtones are weaker at those frequencies. 52 00:03:16,817 --> 00:03:19,497 The result of emphasizing these partials 53 00:03:19,497 --> 00:03:24,889 is a distinctive ringing timbre called a singer’s squillo. 54 00:03:24,889 --> 00:03:28,469 Opera singers work for decades to create their squillo. 55 00:03:28,469 --> 00:03:30,329 They can produce higher frequencies 56 00:03:30,329 --> 00:03:35,276 by modifying the shape and tension in their vocal folds and vocal tract. 57 00:03:35,276 --> 00:03:38,536 And by shifting the position of their tongues and lips, 58 00:03:38,536 --> 00:03:42,536 they accentuate some overtones while dampening others. 59 00:03:42,536 --> 00:03:46,556 Singers also increase their range of partials with vibrato–– 60 00:03:46,556 --> 00:03:50,835 a musical effect in which a note slightly oscillates in pitch. 61 00:03:50,835 --> 00:03:53,415 This creates a fuller sound that rings out 62 00:03:53,415 --> 00:03:56,685 over the instruments’ comparatively narrow vibratos. 63 00:03:56,685 --> 00:03:58,355 Once they have the right partials, 64 00:03:58,355 --> 00:04:01,803 they employ other techniques to boost their volume. 65 00:04:01,803 --> 00:04:05,803 Singers expand their lung capacity and perfect their posture 66 00:04:05,803 --> 00:04:08,433 for consistent, controlled airflow. 67 00:04:08,433 --> 00:04:10,223 The concert hall helps as well, 68 00:04:10,223 --> 00:04:14,465 with rigid surfaces that reflect sound waves towards the audience. 69 00:04:14,465 --> 00:04:17,075 All singers take advantage of these techniques, 70 00:04:17,075 --> 00:04:21,337 but different vocal signatures demand different physical preparation. 71 00:04:21,337 --> 00:04:24,152 A Wagnerian singer needs to build up stamina 72 00:04:24,152 --> 00:04:28,012 to power through the composer’s four-hour epics. 73 00:04:28,012 --> 00:04:31,612 While bel canto singers require versatile vocal folds 74 00:04:31,612 --> 00:04:34,413 to vault through acrobatic arias. 75 00:04:34,413 --> 00:04:36,813 Biology also sets some limits— 76 00:04:36,813 --> 00:04:39,873 not every technique is feasible for every set of muscles, 77 00:04:39,873 --> 00:04:42,833 and voices change as singers age. 78 00:04:42,833 --> 00:04:46,023 But whether in an opera hall or a shower stall, 79 00:04:46,023 --> 00:04:49,173 these techniques can turn unamplified voices 80 00:04:49,173 --> 00:04:51,342 into thundering musical masterpieces.