Is my room big enough for the Harbeth HL5's?

As a former Compact 7 owner who has used those speakers in two different listening rooms (which were slightly smaller and significantly larger than yours) and heard the HL5's in several settings my advice would be to invest your funds in upgrades to other parts of your system. Both are fantastic speakers but I would say that the C7 is ideally suited to the size room you have. While the HL5 would probably work well in that space they would ideally like a little more room to breath. I don't know if the money spent on upgrading the speakers would be as well realized as an equivalent amount invested elsewhere in your system. I don't think you can go wrong either way but if it were me I'd upgrade what was feeding my C7's and stay with those.

A parallel thread is running here:

http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1303719698

I think the thing you have to consider with the Harbeth's is that they are quite forgiving of room size, ancillary equipment and placement. HOWEVER, they are remarkable speakers that can really sing if you get them out into the room and away from the boundaries. This becomes more important as you move from their smaller to their larger models. If you read my initial post carefully I did not say the HL5's would not sound good in your room. Rather my point is that given the cost differential and the size of your listening room it is my opinion that you would be better served by keeping the C7's and investing the difference that you would have spent on the HL5's into other equipment upgrades. I don't claim to be an expert about a lot of things audio but I do know the Harbeth's pretty well and just wanted to clarify my prior submission.

You may want to post over on the Harbeth forum. Many users there and plenty with smaller rooms as they are largely from Europe or Asia.

By my reading nobody has said that the OP's room is too small for either speaker.