I guess it is difficult to give advice about a problem without hearing it personally but it is hard to see how bad room acoustics could give "grittiness". Bad acoustics could give rise to bad soundstaging, odd resonances, loss of definition, but I still suspect grittiness to be back at the first stage. However that is not decrying the good suggestions for improving the room. This room here is very highly damped and that seems to work well.

Acoustic memory is a very tricky thing and most are unreliable, even for a few moments. This makes the work of the clever salesman so much easier so he can concentrate on selling the product through his pleasant engaging personality. Apologies for the cynicism but I've been caught by this many times in the distant past.

However the improvements which good modders like Steve Nugent can bring have to be heard to be believed. A modder Luddite for years, I failed to accept that manufacturers would not implement such improvements in their products to make them more competitive. The two factors overlooked in this approach are (1) the multiplying effect of even a few cents more have on the end price of a product & (2) most who buy the components would not hear the difference in sound anyway. In turn this could be because they really are immune to detecting poorer sound or have such mediocre associated equipment no one could ever hear it anyway.

Fortunately manufacturers like Meridian have raised the bar somewhat, abeit at a high price. That is where the modders can slip under that radar and offer significantly better results from otherwise ordinary sounding components.

But there I go, rambling off topic yet once again!!

John