RONNIE JAMES DIO is not exactly a subtle guy. Take a look at how many names he uses; if that doesn't drive the point home, he's taken care to call his band "Dio." No ego problems here.

Coming up through the ranks of Rainbow and Black Sabbath, he developed a style that was blaringly bombastic, making the most of his strong upper register and wide vibrato, easily slicing through the heavy-metal thunder of his bandmates. Since going solo in 1983 he hasn't fleshed out the formula much, simply reshuffling the components so his voice decisively dominates the guitars.

Which, by rights, ought to have given him a strikingly commercial sound. Somehow, though, things haven't worked out that way. True, "Time to Burn," the sole studio track from the otherwise live "Intermission," has all the right instincts, but between the self- conscious arrangements and the singer's preening delivery, it falls flat.

Still, that's an improvement on the concert cuts, which find his vocal vibrato so out of control that he's frequently singing sharp.

Perhaps Dio ought to take a tip from Accept, an unfortunately underrated German band that's probably the best heavy-metal act on vinyl today. It isn't simply that the guitar work is hard-hitting and efficient or that singer Udo Dirkschneider provides plenty of lung power without grandstanding or overstatement. Rather, as "Russian Roulette" shows, Accept harnesses its musical muscle to ideas beyond the usual "gonna rock all night" drivel. Brawn plus brains makes an unbeatable combination.

DIO -- "Intermission" (Warner Brothers 9 25443-1);

ACCEPT -- "Russian Roulette" (Portrait BFR 40354); both appearing Friday at Merriweather Post Pavilion.