Just wondered what people thought of the difference between

a) boy trebles and lady sopranos
countertenors and contraltos

Personally I think that boy trebles and countertenors work best for most choral works, and for a lot of oratorio stuff as well, or just generally music from the Baroque era... although they do have to be good!!!

But for later works, such as Classical opera and Romantic song, I think contraltos and sopranos suit them better!!!

I have worked with a dear college friend of mine who is a counter-tenor on a couple of duet recitals where the central work was the Pergolesi Stabat Mater.

Counter-tenor soloists certainly work well in Bach, but where the part was composed for a woman, I would rather hear a contralto. A good treble soloist sounds great where a big sound is not requires, but do not rule out a female soprano.

A good counter tenor, is much more versatile than they first appear. 19th Century music may not have much to offer, but 20th century stuff, certainly has. There sound is totally different from a contralto, and works well with a soprano, but you do have to watch intonation and vibrato speeds.

One of the most amazing choirs I have heard was a combined effort in Durham, the Cathedral choir (lots of young males voices plus some excellent men singing) and one of the best choral ensembles (mixed voices) The combined effect was wonderful, with amazing tenor and bass sounds, and the combination of all the sweetness of boys' voices and the texture and power of good trained female voices. Fantastic! I think it depends on the work, but I have to say my one experience of that mixture was quite amazing.

I think older choral music suits the four male voices better, no surprise given that's what it was written for. That said, the Tallis Scholars use a soprano going easy on the vibrato and using what sounds to me like singing from the head more than usual. Using a soprano rather than a treble was probably a necessary trade-off given the complexity of some of of the works they sing.