very interesting ...
Thanks for the information...
The other is a recording of Didos Lament ("When I am Laid In The Earth") featuring Emma Kirkby. It starts off very quiet, and Kirkby doesn’t have the biggest voice compared to others that have recorded it (Jessye Norman, etc) but the volume and intensity ramp up and Kirkby has laser like intonation; I have found that systems that get this right will do well by vocal recordings