None. Unless we're intentionally speeding up or slowing down.
And time fluctuations aren't the same as feel (which is the focus of the John Bonham video above). You can still have perfect timing but have a feel that's slightly behind the beat. It's enjoyable to play with a drummer who has great timing but a different feel than other drummers. It's completely unenjoyable (and often exhausting) trying to play with a drummer with bad timing. I can deal with (not happily!) fluctuations in the snare, but if the kick is all loose goose, then NO THANKS.
And time fluctuations aren't the same as feel (which is the focus of the John Bonham video above). You can still have perfect timing but have a feel that's slightly behind the beat. It's enjoyable to play with a drummer who has great timing but a different feel than other drummers. It's completely unenjoyable (and often exhausting) trying to play with a drummer with bad timing. I can deal with (not happily!) fluctuations in the snare, but if the kick is all loose goose, then NO THANKS.
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