Tesla’s Jeff Keith was interviewed by  “That Metal Interview” podcast, where he was asked what’s his secret to keep his voice in shape. Here’s what Keith said:

“Well, I’ll tell you one secret. We started dropping things down to, instead of in E, the key of E, we dropped it to E flat. On particular songs, where I sing really high, I don’t even know how I hit the notes back then in the ’80s and the ’90s, but I think they can drop as low as… there’s E flat, and then you can drop as low as D.

”And on a couple of songs we drop down to the D tuning, so I can sing the same melody but dropped down a whole step. And from what I understand, you can’t drop any lower than that, or the strings are so loose [that they are too floppy to play]. So, we just dropped some keys, and then we tried it on a couple of songs and when we even dropped down a whole step, I still can’t quite hit the notes (on some songs).”

“Once again, I don’t know how the heck I hit them notes way back then, but all I know is from ‘Into The Now’ on, I started thinking about, ‘Hey, I’ve gotta watch out what key we’re doing it in, because next thing you know, I sing something that I can’t go out there and do it night after night live.’ I mean, it is 37 years later, so…”

He went on:

”So, with ‘Forever More’, ‘Simplicity’, all that stuff, I just started keeping in mind, ‘Hey, whatever you write, you’ve gotta sing it night after night.’ Back in the ’80s, and stuff like that, I wasn’t thinking about it. You just do 20, 30 takes of something, pick the best out of it, and go, ‘Hey, there you go. That’s great.’

”But I never had the thought in mind of, ‘Hey, you’ve gotta go out there night after night and sing it.’ And back then, I could, thankfully, but today, it’s, like, ‘Hang on a second.’ I’m gonna turn 65 in October. It’s, like, ‘Hang on now.’ I’m starting to fill out forms for Medicare and all that stuff. So (I’ve gotta) be careful with what melodies I come up with because I’ve gotta be able to do it night after night.”