Pennsylvania State Rep. Peter J. Daley has introduced legislation that would require entertainers using pre-recorded music in concert to say so - both on tickets and in advertisements.

Daley, a Democrat, says the bill would apply to both lip-synched vocals and to instrumentals, everything from drum machines to "sequenced" parts, which are programmed beforehand and essentially played by a computer."A live concert is, by definition, music performed. And that's not music performed; that's music pantomimed. I think when people pay $30 or $40 (for a ticket), they should be informed."

Although the groups don't like to admit it, it's common knowledge that dance-pop acts including Milli Vanilli, New Kids on the Block, Paula Abdul, Madonna and Janet Jackson all lip-synch at least part of their lead or background vocals.

But it's a good bet the majority of touring acts use some kind of pre-recorded instrumentals, trying to re-create the sound of the drum machines, sequencers and sampled "loops" of old recordings they use in the studio.

Trish Heimers, vice president of public relations for the Recording Industry Association of America, said "lip-synch" bills have been proposed in at least two other states - New Jersey and California. The RIAA hasn't taken a position on the bills, she added.