Yes, I know there are many differences between singing Rock music and Opera. But the main difference is in the size of the consonants, or, more importantly, the balance between consonants and vowels.
Rock music has massive crisp consonants that outweigh the vowels substantially when you're singing. This is true for many 'popular' forms of music.
In Opera it's all about the vowels ringing out and, in some cases, the consonants become almost non-existent.
Let's take two examples : click on the titles to hear on YouTube
Living on a Prayer by Bon Jovi. Jon Bon Jovi's vocal is crisp and he punches all the consonants, this is what gives the song its drive.
Nessun Dorma by Luciano Pavarotti. One of the great operatic ballads. Listen to how the vowel is much more dominant in the song and the consonants are less important than in the rock song, they also are much slower and less punchy.
You can obviously sing Living on a Prayer as an operatic song (if you softer the consonants), and Nessun Dorma as a Rock song (by making the consonants much more punchy and crisp).
When we talk most of the time our consonants are punched in much more of a rock style than an operatic style. If we, in speech, don't make our consonants punch we sometimes sound lazy, if we are presenting to anyone we tend to make our consonants punch more.
The punchier and most crisp we make the consonants the more the song we are singing will sound conversational, which in many cases is what we want. Most popular songs are written as a conversation and therefore to get the audience to empathise with us the more the consonants need to punch.
This is obviously not true of every song, but it all depends on the style of song. Musical Theatre in the 50s and 60s stylistically had much more in common with Opera than many of the shows being written today. In 21st Century Musical Theatre many of the songs, and indeed shows, have more in common with popular music than Opera. Again this is not true for every show but again here's two examples, one from the 1950s and one from 2018.
Although these are both in the same genre (musical theatre) the consonants are much punchier in the Mean Girls song than in the song from Carousel.
Some consonants are instantly punchy, ie T - P - B - C - D (it's impossible to these anything but punchy) , but some are more tricky and the slower these get the less punchy the song will sound. The main culprits for being slowed in song are L - H - M - R - F. Whenever we have double consonants i.e. CH, ST (even occasional treble consonants STR, NGS) the more we naturally slow things down. Getting through the consonants quickly is important with these, and when we have a ballad these are even more delayed as we have a natural tendency to slow the consonants when the music & singing is slower.
I'm not saying that one is better than the other, it's just being aware that if you want a song to sound more poppy/punchy then making the consonants pop is one of the ways to help your performance.
Singing Tips | The difference between rock music and opera : The Consonants
