Lumping Mudhoney in with the Seattle sound is like nailing jelly to a tree.

"I like the Temptations a lot, especially 'Psychedelic Shack,' " says Mudhoney co-founder and lead singer Mark Arm from the Seattle offices of Sub Pop records. This may seem a strange statement from the man credited with coining the term "grunge" to describe the metallic punk sound that emerged from the fog of Seattle's '80s and '90s suburban sprawl. But it was Motown that provided the upstart Sub Pop label with many of its cues for visual design and business organization.

Considering punk and grunge's stylistic debt to Motor City groups like the Stooges, Mudhoney fans found it no surprise to hear that Arm was doing a brief stint as lead singer for Detroit's MC5 back in 2004. This nod, from Seattle to Detroit, is especially evident on Mudhoney's 2006 CD Under A Billion Suns, on which the solid thump of factory rhythm carries excited vocals and guitars thrashing in electrified dirt.

As for comparison with peers like Pearl Jam, Alice in Chains and Soundgarden, Arm says, "They're friends of ours, but musically I don't think we have a whole lot in common except that we play rock 'n' roll." These days, Arm is more likely to compare his band to the recently formed San Francisco act Comets on Fire than to any historic Seattle group.

Noting that Mudhoney's work in recent years sometimes jumps entirely off the grunge map, Arm says matter-of-factly, "At this point I'm like 44 years old, and our [band's combined] record collections are vast. But I don't think we had much to do with heavy metal. There were some bands that were thought of as metal, like Black Sabbath, Motor Head and proto-metal bands like Blue Cheer. But the real rigid anal chugging guitar things you hear in Metallica, Iron Maiden or Slayer bring me no joy."

As to what impact nearly 20 years of touring and seven CDs has had on Mudhoney's work methods, Arm explains, "We all kind of write the music together. It hasn't changed that much. We are old men and are stuck in our ways of doing things. We work quickly in the studio."

One thing that's inarguably clear is Mudhoney's increasingly political stance. With song titles like "Where Is The Future?" "Empty Shells" and "Hard-On For War," Mudhoney express what Arm calls "a reflection of the times and the frustrations that come with them." In his opinion, "It's pretty brutal over here [in the United States]." And if listeners are looking for a blues influence, Arm admits, "It's in there."

Experimentation still has a role in Mudhoney's sound. Perhaps the most extreme case of this is a 30-minute-plus hidden track titled "woC eht rehtorB yM" on the band's 1995 Reprise release My Brother the Cow. An even more effective use of experimentation has been their recent collaborations with Seattle's avant-punk-jazz wizard Craig Flore. His edgy brass arrangements began lending their spice to selected Mudhoney tracks in 2002, with their Sub Pop release "Since We've Become Transparent," and continue on the band's latest CD.

Although Flore's brass section will not be making the trek to Europe, this uncompromising band — known to list beer among their technical requirements for concerts — is, according to Arm, "really looking forward to coming to Prague and hanging out for a couple of days."