Couple of xtra comments..room is actually 26 by 12'4"....not counting that alcove under stairs. Also, the lighting looks terrible in these pics! ..but room in very nicely lit, and the camel/beige is newly painted...would kind of like to keep it, since I like it, and actually paid painters, instead of doing the hard labor myself!

You're thinking for performances? We would actually use the space very casually to play around, not really perform. So, seating can gather around a coffee table, or something like that, not necessarily facing forward to the drums. A couple of chairs that look cool and swivel possibly, paired with a loveseat or something?

You can check out Candace Olsen off of HGTV check her website she might have a solution
Bridgette

So, I start with 'barn door style' sliding doors where you don't need the doors to match another room -- it will make for less bulk when opening the door, and they come in some nice styles that do not look like barn doors -- search in HOUZZ.

Right now it looks like the drummer would get whapped by someone coming in that door behind him...and that does not look like one that could be turned into a barn (flat to the wall slides; like an exposed pocket door). So I'd move the drummer out of the walking flow of the room, and then look for a couple of apartment sized sofas or an L shaped unit to make a seating area. If you want to make one end a 'stage' for the musicians, then you could have one seating area facing them (audience) and back that with another seating area ... given your length to width ratio -- you probably want to break the space up into zones but keep the 'walk-thru' traffic path from being either a straight line or TOO impeded.

Consider swivel tub chairs opposite a sofa -- can turn to either grouping

Thanks for the comments...! As for the doors behind drummer, it's actually just the access to furnace / water heater area (probably a 12x4 space) The doors are almost never opened..so the drummer is safe! :-) It's an interesting idea, though, to consider changing up the look of the doors, if nothing but to add interest in the look!
Apartment sized sofas are probably the right way to go.....how many chairs do you think can really fit in the space?

depends if you like large overstuffed chairs or prefer leather tub/club chairs

https://www.google.com/search?q=tub+chair+swivel&tbm=isch&tbo=u&source=univ&sa=X&ei=W4GXUqysBo_woAS1qoDoCw&ved=0CEgQsAQ&biw=1270&bih=728

I find it best to decide what I want to do in the room, and then browse until something catches my eye. Padded leather coffee table in between sofa and chairs can double as extra (backless) seating for a performance if the group is < 30 years old, not so likely if it's grandma/grandpa down there.