Merging threads a bit...
I have the ADA 1500 M100S VP 180 4 QS8s. thinking QS10S OR EP 500. My room is about 2600....
I have not had a chance to compare QS10s with QS8s so take this with a grain of salt, but my main reasons for updating would be:
- I had a large room and QS8s were starting to be the weak link in terms of SPL+quality
- I wanted to run at a lower crossover frequency than the QS8s are comfortable with (~80 Hz)
In your case both of these potentially apply, in the sense that the QS8s are definitely the "smallest" speaker in your system and all of your other speakers are able to cross over at much lower frequencies than your QS8s.
Where it gets more complicated is that your room isn't what I would call too big for QS8s unless you are playing at very high SPLs... but since the rest of your speakers are very capable and you have enough power you could very well be doing just that.
That said, once you raise the topic of spending your $$ on upgrading surrounds or adding an EP500 my first thought is the same as Matt's, basically that you can never have enough good subwooferage.
A few questions that haven't been asked yet:
1. What do you have in the way of subwoofer(s) now ?
2. What crossover frequency are you running at, and is your receiver / pre-pro able to set different crossover frequencies for different channels (like my old HK 630 can) ?
3. How loudly do you run the system ?