What makes a timeless riff? In this edition of Loudwire's Gear Factor, powered by Sweetwater, The Music Experience's Squiggy talks with Tremonti's Mark Tremonti and Eric "Erock" Friedman about what riffs will stand the test of time and the guys weigh in with some pretty legendary suggestions.

"I think the simplest ones [are often timeless], the old school ones that just stick in your head right off the bat. There's nothing better than that 'Smoke on the Water' riff. Everybody knows it right off the bat," says Tremonti, who breaks out a bit of the Deep Purple classic.

Friedman suggests Metallica's "Enter Sandman," taking some kidding from Tremonti about being from a younger generation. He also plays a bit of the instantly recognizable AC/DC "Thunderstruck" riff. Watch the two musicians playing in the video above.

Squiggy also talks to the musicians about being part of the PRS Family, with Tremonti detailing the painstaking process of coming up with his signature guitar and SE edition.

"I love PRS and they sent me out some guitars. I love the guitar, but the switches are in the wrong spots," recalled Tremonti. "I grew up on Les Paul. So once we put the switches where I wanted them, I still didn't like the tone as much. It was a little rounder than I was used to, so after giving them back five guitars back and forth, it was like why don't we just make a guitar that you want to play."

The guitarist says it took a while before they came up with the right aesthetic and look, but one of the things he most loves is the pickups. "Once we got the aesthetic done, the pickup was really important. They have hot pickups at PRS, and I've had people come up to me and say they love the pickups and I love it," says the guitarist.

As for the SE, Tremonti couldn't be more pleased: "When I saw the SE and saw how much it cost and I played it, it was like you did it perfect. It is the best guitar for that price that I've ever played."

The guitarist is also beaming over his MT15 amp, which is a current popular seller in the industry. "I'm very proud of that amp, and I'm an amp fanatic. I was really weary about bringing that amp out because I didn't want to hear anything negative about it. I'm more in tune with amps than I am guitars," says Tremonti, "But I designed that amp and it came out and we went to NAMM with it and it got Best in Show, I was as happy as a kid in a candy store."

Learn more about Mark Tremonti's signature guitar and SE Models here, the MT15 amp here and be sure to visit Sweetwater.com for all of your gear needs. Tremonti are currently off the road as the guitarist returns his attention to Alter Bridge. Keep up with Tremonti's activity here.

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