Opera fans argue about singers with a vocabulary that sounds like a private language: squillo, a wobble, a spread top, aspirated runs, covering in the passaggio. Behind each word is something you can actually hear, once someone points it out.
This page points them out. Each section takes one property of a trained voice, lets you bend a synthesised voice until you hear the difference, and then sends you to real recordings where the same thing is done well, or badly. At the end there is an ear test and a glossary.
π§ Every figure plays sound; headphones help. On an iPhone, if nothing plays, switch off silent mode. The voice is synthesised: a buzzing oscillator shaped into an βahβ. It changes one thing at a time, which no real singer does, so treat it as a diagram you can hear.
Operatic technique exists to solve one problem: to be heard over an unamplified orchestra in a large hall, for three hours, night after night, while staying beautiful and saying the words. Almost every fault is a shortcut that trades one of those things for another.
So when you listen, ask five questions, roughly in this order. The first two can be answered from a single held note.
Two more questions apply throughout: can you understand the words, and does the singer sound the same in the last act as in the first? Fatigue is the honest test of technique.
A trained classical voice oscillates in pitch by itself when it is free. This vibrato is not added on purpose. It comes from the balance of the muscles in the larynx under steady breath pressure. Measurements of professional opera singers typically find a rate of about 5.5 to 7 cycles a second and an extent of roughly Β±Β½ to 1 semitone. The ear fuses that into one warm pitch at the centre.
When the rate drops and the swing widens, the ear stops fusing it and hears two pitches taking turns: a wobble, common in tired or ageing voices and in singers who push. When the rate climbs above about 7.5 cycles a second with a narrow swing, it becomes a nervous flutter, the bleat (Italian caprino, goat-like). No vibrato at all is straight tone: a deliberate colour in early music, but pale and tight-sounding in Verdi.
Play the voice and drag the dot across the map. The lower strip shows two seconds of the pitch it is singing.
The zone borders are teaching approximations, not rules. A slightly fast vibrato can be charming in a light French soprano, and many singers of the 1920s and 30s had faster vibratos than todayβs taste allows.
Musicians measure small intervals in cents: 100 to the semitone, 1200 to the octave. A vibrato of Β±50 cents swings a quarter-tone either side of the note. In Johan Sundbergβs measurements of trained singers the rate sits between about 5.5 and 7.5 Hz and the extent between Β±50 and Β±100 cents; the perceived pitch is close to the average of the swing.
Because the voice is always moving, intonation is heard at the centre of the vibrato. Play the drone and move the voice away from it. Within about ten cents most listeners call it in tune. By twenty-five you hear a slow beating against the drone and a sour colour. Singers who go flat on top are often tired, under-supported or darkening too much; singers who go sharp are usually pushing.
An orchestra puts most of its energy below about 1,000 Hz. Trained opera singers, especially men and the lower womenβs voices, learn to cluster extra energy between about 2,500 and 3,500 Hz, where the orchestra is comparatively quiet and the ear is most sensitive. Acousticians call this the singerβs formant. Singers call the sensation squillo, βringβ or βpingβ, and teachers talk of singing in maschera, in the mask of the face.
Ring alone sounds hard and nasal. The Italian ideal is chiaroscuro, bright-dark: a bright core inside a round, deep body. A voice with depth but no ring sounds muffled and is swallowed by the orchestra. A voice with ring but no roundness sounds thin and harsh.
Play the voice, add the orchestra, then switch the ring off and on. The shaded band marks the singerβs formant.
With the orchestra on, the voice without ring is almost gone, although its overall loudness has hardly changed. This is why a ringing voice like Jussi BjΓΆrlingβs seemed to float over the pit without effort, while a bigger but duller voice can sound loud in the room and still vanish in the hall. The companion page Overtones explains formants, the resonances that shape every vowel.
The onset (attacco) is how a note begins. Ideally breath and vocal folds start together and the note simply appears, on pitch. Air first gives a breathy βhβ; folds clamped first give a hard click in the throat. Arriving from below the note is scooping, one of the most common faults and impossible to unhear once noticed.
Legato, the unbroken line, is the foundation of Italian singing: the vowel keeps sounding from note to note, consonants are quick, the breath never stops. A deliberate slide between two notes is portamento, an expressive tool used sparingly and on purpose. The difference from a scoop is intent: a portamento joins two particular notes, a scoop is a habit of starting every note low.
Coloratura or fioritura is the florid writing of Handel, Rossini and Donizetti: runs, leaps and trills. Clean coloratura keeps the legato inside the run, each note distinct but the tone never stopping. Two faults bracket it. Aspirated runs put a small βhβ before each note, so the pitches are clear but the line is chopped. Smeared runs slide through the notes until the pitches blur.
The voice has more than one way of vibrating. Low down, the vocal folds are thick and meet over their full depth: chest voice (voce di petto). Higher up they thin and stretch: head voice (voce di testa). The zone where one gives way to the other is the passaggio. For tenors it lies roughly between E4 and G4, for sopranos roughly between E5 and Fβ―5; every voice type has its own.
A well-trained singer smooths the transition so you hear one voice. Part of the craft is vowel modification (aggiustamento) and, for men, covering (copertura, or girare, turning): rounding the vowel slightly while rising so the top stays round instead of spreading. Two things go wrong. A singer who carries the open, heavy sound straight up spreads: louder, brighter, tighter, until the top cracks or goes sharp. A singer who cannot negotiate the shift has an audible break, a gear change where the colour suddenly thins.
Not every audible register shift is a fault. Many mezzos and contraltos, Marilyn Horne and Ewa PodleΕ among them, use an exposed chest register as a deliberate colour in Rossini and Handel. The question is whether the singer controls the shift, or the shift controls the singer.
The messa di voce, a held note that swells from soft to loud and back without changing colour or pitch, was the old Italian schoolβs proof of control. Mezza voce, half voice, means soft singing that keeps its support and its ring, as opposed to merely quiet and breathy. A singer who cannot sing a high note softly is often holding it up by force. When a score marks a high note pianissimo or morendo, dying away, listen to whether the singer does it.
Use this table when something sounds wrong and you cannot name it. Teachers disagree about causes and cures; the sounds themselves are widely agreed on.
| Name | What you hear | Usual cause |
|---|---|---|
| Pressed, pinched | Thin, hard, edgy tone; effortful high notes; tends sharp; cannot sing softly. | The throat squeezing to do the work of breath support. |
| Throaty (ingolata) | Muffled, swallowed, woofy; unclear words; under the pitch; no ring. | Tongue root and larynx pulled down and back. |
| Spread, white (aperta, bianca) | Wide, blaring, shouty; no core; top notes crack or go sharp. | Open vowels carried through the passaggio unmodified. |
| Over-darkened (intubata) | Hooty, manufactured depth; every vowel drifts to βohβ; often flat. | Pressing the larynx down to sound bigger than the voice is. |
| Breathy | Air around the tone; short phrases; fuzzy soft singing. | Vocal folds not closing fully. |
| Nasal | A honk on every vowel. Not the same as ring. | Soft palate too low. |
| Wobble | Slow, wide swing; two notes instead of one. | Fatigue, age, pushing. |
| Bleat (caprino) | Fast, narrow flutter. | Tension in the larynx; too much pressure. |
| Scooping | Notes approached from below. | Habit; poorly coordinated onsets. |
| Aspirated runs | βHa-ha-haβ in coloratura. | Breath pulses separating the notes. |
| Register break | A sudden change of colour or volume at the same place in every scale. | An unco-ordinated passaggio. |
| Mushy diction | Lovely vowels, no consonants, words lost. | Tone put before text. Often a trade-off rather than a pure fault. |
Each recording below is chosen for one thing it teaches. Listen once for pleasure, then again for the one thing named.
The videos come from YouTube. Nothing loads from YouTube until you press βplay hereβ; then the player is fetched from youtube-nocookie.com, which passes your IP address to Google (details in the privacy notice). Uploads come and go: if one has vanished, βother uploadsβ searches for the same recording.
The end of βCeleste Aidaβ. Verdi marks the final high Bβ pianissimo and morendo. Most tenors sing it loud, and many houses expect it. Listen to four or five tenors and only to that note: who honours the marking, who manages a real diminuendo with the tone intact, and who gets louder because they cannot get softer? Start with Bergonzi, who sings it as written. The other players start about a minute before the end of the aria.
βNessun dormaβ. Listen to Pavarotti, then to two or three other tenors, including a crossover singer who performs with a microphone. Ask the five questions on the held notes of βVincerΓ²!β: is the vibrato even, is there ring or just volume, does the top B spread or stay round? A microphone hides a lack of squillo; an opera house does not. For the crossover version, search on YouTube β.
Start with one fault at a time. Each clip plays a short reference pitch, then a held note over a quiet drone. Name what you hear. Clips are drawn at random, so you can keep going.
Real singers rarely have just one problem, and faults travel together: a pushed voice often wobbles and goes sharp, a tired one goes flat and loses its ring. Each clip here is a short phrase, up and down an arpeggio, over a drone on its home note. It may be clean, or have up to three faults at once. Mark every one you hear, then check. βSung cleanlyβ plays the same phrase with every fault removed, for comparison.
mark every fault you hear
No term matches. Try a shorter word, or choose βallβ.
Constantin Lisson Β· 2026