What genre of music is this?

Here's a link to a 1 minute clip I got of a band playing at a bar I was at. I know I couldn't buy any of their stuff, because I'm pretty certain is was improve, but I'd love to know similar, well-known groups who perform a similar genre.

I'm getting a sort of funk/jazz vibe from this. I also LOVE the fact that there isn't a vocalist.

Which genre and similar band names please! Thanks!

Here's the link (be warned earphone users, iPhone microphone has made this very treble>bass and hurt my ears!):

Thanks!

Added (1). Not 'improve' in the first sentence. I meant 'improv' as in improvising.

I guess "funk-jazz" or "jazz-funk" is a good name for this, but it could be called "groove music" or "fusion music" (jazz-rock). Though, as you warn us, the sound quality is very bad, it reminds me very much of the band Tower of Power. I think I can distinguish an organ sound (electronic keyboard) behind the guitar. Earth Wind & Fire has a few instrumental things that sound like this, but many bands produce this type of instrumental groove with guitars vibe.

Like you, I prefer instrumental music and I have heard similar things on the "Groove Jazz" channel at Accujazz.com. You could also search YouTube.com for "instrumental groove with guitars" or some such qualifier. Happy listening.

P.S. Though they are keyboard-driven, Modeski, Martin & Wood have done a lot of this type of groove.