Ok! I put the clip out to my many professional musician friends, and we discussed it. Everyone agrees that it's probably a clip from a Dvorak imitating composer or a wedding gig book. None of us has played it. Everyone was stumped. We all thought it sounded like a cross between the Glazunov you mentioned and Dvorak. Since your cellist plays a ton of weddings and parties (from his website) I'm going to guess it is from a gig book. If it were an actual Dvorak or Glazunov, he'd remember it, or at least one of my string playing friend would recognize it. Shoot- I really thought we were going to solve this for you. Oh well- I guess you should dig into some Dvorak. I can recommend Goldmark- he wrote some beautiful quartets and work in film scoring in Hollywood for a long time. I think you'd love his string pieces. Cheerio!