Classical Music - Terms..

Classic vs Pop.Turando-Classic
An 'Aria'.
The Italian Arias.
Classical Crossover.
Opera  Singer - Opera Voice.
“High Fifth”; High ‘C’
A singers “Octave Range”.
Head Voice vs..
Falsetto.

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Classic vs Pop.

'Pop' is short for 'popular' - but the "popular" does not refer to the 'listen count', it refers to the fact that anyone can sing it. Only one in ten thousand can sing 'classic' because it covers 3 octaves. Most folk cannot sing two octaves - so Pop is written for one & a half octaves. (Most Church hymns cover just one octave.)
The Listen Count of the top Pops is only 5% of the top Classics. That's partly due to the fact that the Classics (as the name implies) have been popular for many generations! Some Arias have been popular for over 200 years! And still insanely popular.
Some 'Pop' bands have discovered the power of the "High Cs" and have recruited a top Tenor. These bands can then write music using 3 octaves and achieve Listen Counts ten times that of other Pop bands. Eg. Ice House, Linkin Park, Cold Play, Elton John, 'Imagine Dragons'..

The Arias.

The Arias are the 'best bits' of the operas, they are the songs that give the listener "Tears & Goosebumps".
The word 'Aria' has the same root as 'spirit' and implies 'Lifting your Spirit' or 'Transcendental'. Ie. an Aria carries you away to a higher place.
As mentioned above, "Only one in ten thousand can sing 'classic' because it covers 3 octaves". With the Arias, only one in a million can sing them because "Tears & Goosebumps" require a pure tone 'high fifth' (G5, A5, B5) - and that is a rare 'opera voice'. (Think Pavarotti or Jackie Evancho)

The Italian Arias..

These are the worlds "Top 100" of all time.. Their listen count can be in the billions..
They have an amazing advantage over other Arias in that most listeners do not understand one word of the lyrics - and therefore, their mind is free to paint its own magical images from the depths of its most mystical imaginations! (Italian listeners do not have this advantage and thus do not rate them so highly.)
As Morgan Freeman said in 'Shawshank Redemption'..
"I had no idea what those two Italian ladies were singing about, and frankly, I don't want to know! (in my imagination) they were singing about something so beautiful it can't be expressed in words - and, for a brief moment, everyman in (this prison) felt free!" (the Aria was 'The Marriage of Figaro' by Mozart.)

Classical Crossover.

Classical Crossover refers to the singing of the Arias (mostly Italian) while ignoring the operas they came from.
As with the Arias, only one in a million can sing them, and, because of the huge popularity of the Arias, they can make an enormous amount of money.
True Opera singers have much greater skills but never make that kind of money. They tend to look down upon Crossover singers. Most Crossover singers do not have an "Opera Voice", nor do they have the pure 'High 5th' required for "tears & goosebumps". They merely rely on the popularity of the Arias to be successful.

“High Fifth”; High ‘C’

'High 5th' refers to the top half of the 5th octave. (5G, 5A, 5B) These are the notes famous for "Tears & Goosebumps". (Sheet music often specifies 'high 5th' assuming Tenors will sing an octave lower.)
For Ladies, 'High 'C'' refers to 'C6' (Soprano 'C' - the top note required for a Soprano)
For Males, 'High 'C'' refers to 'C5' (Tenor 'C')(Middle 'C' is C4)

Opera Voice..

An Opera Voice is a one in ten million voice! It has to..
* Cover 3 octaves; * Be 'Pitch Perfect'; * Have no discernible distortion. (Pure tone)
With "No discernible distortion".. The main reason for this requirement is that all of the hundreds of opera singers around the world have to be able to sing as one voice. That requires them all to have similar voices. A 'Barbra Streisand' voice may be nice, but there is only a few of them on earth.
Most 'distortions' in voices are unique.. Some distortions are common enough to have hundreds that could sing as one (eg. country & western) - but that voice would not suit an opera.
With "Pitch Perfect"..
In most operas, there are periods of minutes where the line of singers stand silently.. Then, as one voice, they all have to hit an A5 perfectly! (in pitch and timing). It will be painfully obvious if one of them is off key by more than a few percent! That takes huge natural ability and (normally) a decade of practice. (we say 'normally' because there was one 10 year old girl who could do that! - and we don't want her millions of fans emailing us!)

A singers “Octave Range”.

The human vocal chords can NOT cover more than 4 octaves..
There is a common miss-conception that some singers can cover 6 octaves. This mistake comes from the crazy policy of the 'Guinness Book of Records' to include ANY useable sound that the mouth can make! That includes whistles and burps. Most 'claimants' do not present with a 'front of tongue' whistle, but a 'top of tongue' whistle can be made to sound like a normal 7th octave voice.
Also, a 'Falsetto' voice can go a whole octave higher than the normal 'head voice'.. (Falsetto is produced by blowing high pressure air past very tight vocal chords causing just a tiny section of the chords to 'squeak' a high note.)
The 1st octave 'claimants' use the modified 'burp' style which is mandatory for all 'Batman' actors.
Note.. "Head Voice" vs "Chest Voice" simply refers to where the resonance occurs.
The Vocal Chords need a resonance cavity to reinforce the sound. Low notes will resonate in the chest, Higher notes need the smaller cavities of the head. Head Voice has nothing to do with 'Falsetto'.

The Vocal Range of the traditional classifications..

Ladies..
Soprano  C4-C6
Mezzo-Soprano G3-A5
Contralto  E3-F3

Men..
Tenor  B2-C5
Baritone  F2-F4
Bass  D2-D4

wip.