I've always used my tulip and then pepperpot Tannoys in similarly-distanced configurations. I've also heard the Glenairs (both models) many times. There are differences in sound between various models, but all were coherent at short distances. Though the Glenairs are not my favorite Tannoys, I do like them, and they're pretty neutral -- certainly not bright. It's unfortunate to hear about your troubles, and I'd suggest spending some time investigating whether any upstream gear or even connections may be the culprit.
Though you may be dealing with significant back-wall reflections, since you're firing down the short dimension, in my experience it's still very difficult to "drag a Tannoy down with the room". Thus, I would suspect some kind of electrical/matchup issue before room acoustics.
Though you may be dealing with significant back-wall reflections, since you're firing down the short dimension, in my experience it's still very difficult to "drag a Tannoy down with the room". Thus, I would suspect some kind of electrical/matchup issue before room acoustics.