MP's assertion that it gives him a different vibe.......well I guess only he'd know. I wouldn't argue if he says so but I still have to ask what could be done on the single kick kit, could be done on the other. It was just two kits.
Well, I'm sure you
could do anything on a single kick kit. Peter Wildoer seems to have handled the DT drummer audition just fine with only a single kick drum setup. But I still completely get having the two kits together. As already pointed out, the drums on the single kit and different from the drums on the double kit. They sound different. It may not be an appreciable difference to some listeners, but others can and do pick out the different sounds. And it's not really any different than a guitar player switching between different guitars during a gig (as far as songs that do not require different actual tunings, or require an extra low B string, for example). Is there any reason Adrian Smith needs to switch between his Les Pauls and his strat style guitars during any given Iron Maiden show? For songs that are in the same tuning, wouldn't just one guitar be enough? Yeah, he
could just have one guitar for each tuning. But as a musician, even if the differences in sound are very subtle and not noticeable to the average listener, he likes the differences in tone, sustain, and other areas, and likes the different feel, and he feels that certain sounds are more appropriate for certain songs. So he switches it up. Same with Portnoy using a larger drum kit with different sounding bass, snare, and tom drums. It's just that it is less conventional for a drummer to do that.
And, for the record, here is Mike's statement on that issue, just so we can make sure we are being accurate about his reasoning:
MP: I had been using my last setup for the last two albums and tours, and I felt that it was time for a new kit. When I started to put it together I was faced with the decision of going bigger or smaller. I had been using smaller kits on the Transatlantic and Liquid Tension albums. Most of the clinics I had done were also on a smaller kit, and I was really starting to enjoy it. But the more I thought about it, I felt that going smaller with Dream Theater just wouldn't be appropriate. I didn't think the fans would accept seeing me perform on a smaller kit. I can remember when Neil Peart scaled down to a single bass drum. As a fan, I was disappointed. So I came up with the idea of putting together the small kit with the big kit and incorporating it all into one huge kit. It's set up so that I can play certain songs with one kit, and then move over to the other kit for a different sound.