After reading some of the threads below and listening to just about everything in the archives i can only conclude that on the whole the level of musicianship far exceeds the quality of the singing in the progressive Rock genre. Sure there are some quirky singers that have a charm of their own eg. Ian Anderson,Peter Gabriel and some high pitched rock singers eg  Geddy Lee who is a master of the style but all in all there are not too many exceptional singers who have tonal qualities and technique that make them great. Jon Anderson comes to mind and the best example is when he sings a duet called chagal from change we must. Here he is singing alongside a classically trained opera singer and sounds beautiful.

Even Peter Hammill who is often held up as an example of great singing is often found floundering as he overreaches or starts off in the wrong key or hits the wrong note

Overall the general level of singing could be better

One former Prog vocalist who was a refreshing exception to this rule was John Wetton. Wetton had an authoritative tone that really carried, like a natural echo or something. Greg Lake's voice was similar in this respect also. Voices like those would have been neat to hear with some of the music by Genesis, Yes and Rush....when those groups were in their prime that is.

I've criticized Peter Gabriel's failure to sing decently ('71-'73 era only) with Genesis, on a few previous posts. I've done this only because I liked their music so much, otherwise. Gabriel was a most effective showman though. Yet I was always displeased with those deep croaks 'n' grunts he used (Genesis Live), in lieu of notes.

Also: I've heard a limited amount of a recent album by Rush - I think its called Feedback or something similar - where they do covers of really old classic rock tunes. Geddy Lee's voice sounds good for a change; very level. So I'm not sure why he chose to squeak and screech during their prime years. But they did well nonetheless, obviously.

The problem with vocalists in prog is that a great percentage of the musicians are classically trained in their respective instruments but the singers not (At least in singing), so the difference between a well trained musician and another not trained is evident, despite the natural vocal range.

Classic music (One of the main influences of Prog) is mainly instrumental and chorale so the only classical training for singers would be Opera,  honestly I don't know any Prog' vocalist who had operatic formation, except maybe Annie Haslam and Francesco di Giaccomo from Banco who I believe have some training in Italy and Freddie Mercury who I'm sure had formal musical education in India and read somewhere was part of a classical choir (Not sure of this last one).

But people forget that despite this classical influence, Prog' is mainly Rock, in this case a tenor would be too much for the genre and probably would almost never sing in a popular music band (Except after they made enough money with opera like the three tenors).

But bands like Genesis, Yes, ELP, Jethro Tull, Kansas, Rush, Pink Floyd, etc, wouldn't be the same without vocals.

Iván

The singer in Deux Ex Machina is the closest I have heard yet to an operatic tenor doing prog. I saw them at one of the progfests in LA years ago.

I think the singer in The Mars Volta is very good as well.

What lets most prog bands down more than the singers is the lack of a really good song. Yeah, you need instrumental virtuosity but you must have a solid composition to build on and that's what I find lacking more than anything else (if one is looking for weak points among prog bands).

If you want a singer that sounds like opera, try Klaus Nomi. He would also be a good contender for a poll about "weirdest stage appearance".