You're right the Auto-Tune can be heard well in some DSABH songs. For example Please Don't Let It Go, during the 2nd verse "death sings our song" it's obvious when it corrects the vibrato. I think every album except Greatest Lovesongs has Auto-Tune or Melodyne. It's very slight. I am not sure about Tears On Tape, could be very slight. There is one flat note in the first chorus of Drawn & Quartered :p
In my opinion Ville's best live vocals were during the America 2007 leg. He is very well on key on Digital Versatile Doom. For example St. Gallen 1999, so off-key. I bet his ear monitor sucked during that gig. Anyone noticed the chorusy kinda effect during the 2013 tour? Ville sang very well on that year.
For me it's hard to listen if a singer is not in key.
YES! The 2007 north america gig was good because the whole band tuned down the songs and Ville has an easier time singing at a lower key (Like Jyrki69 from the 69 eyes he has a deep voice)
they played that way until 2008 I believe.
I think during 1998 to 2000 or so not only did he have problems with the key because of equipment, but I think he was trying to "find his sound" Like Linde starting in 2003 or so, he started using wah for his solos, but now, it seems he has "mastered his sound" almost to the point where you know what the solo will sound like before he plays it.
I thought it was most obvious during Dark Light that they didn't use Ville's natural Voice for many reasons, mainly because they were trying to give their best "polished" product. But during the few gigs we saw in 2005 (Rock am Ring and Download Festival) I think he did a great job, although he may have been sick
I did notice during the 2013 tour, he used either chorus or some kind of effect, I think because he didn't have Mige and Burton backing him up