Rethinking my system: Your ideas are appreciated

Are you using active high pass on the monitors, or are you running them full range, with the sub simply augmenting the lowest octaves?

If you're not running an active XO between sub and mains, adding the ability to cut everything below 80Hz from the mains will allow them to play with more dynamic range for two reasons:

Reduced excursion requirements on the mains allowing cleaner midrange reproduction

Reduced peak to average ratio on the amplifier, allowing better dynamic peaks for more realistic impact.

With the size of your room, you really need something bigger to load the room if you are looking for fullness instead of pinpoint imaging. At your budget, I would recommend the PSB Golds. You then might need more power to do the speakers justice in that room. Something in the 250 wrms range. I liken your current system to a turbo 4 engine in a car. Might have enough horsepower, but not enough torque, like a V8 would have. You need more torque

i vote with the upgrade-the-amp folks. your dynaudios (which i really like) are very inefficient at 84db, while your avr is rated at only 75w/ch. like manitunc says, you need more torque--even if you were to upgrade speakers you might find your rotel can't cut it. you can find a nice used parasound or comparable for a few hundo. you're also getting good advise re: setup.

I have not tried a dedicated power amp, but I'm thinking that's the way to go here. As much as I love the Dynaudio sound, I still think they're a bit too small for my area even with the added power amp. I will probably get floorstanders to move more air.

I looked at the Anthem 225 — any other suggestions for integrated amps? Also, many of the integrated amps I've looked at don't seem to have sub outputs - just 2-channel for mains. Any way around this to hook up the sub?

Since you're using a 7-channel (with 5 powered channels) AV receiver and have a subwoofer, is this a surround HT system or are you using it for 2.1 ch. stereo?

I notice you're considering changing to a 2-channel integrated (Anthem 225), so I'm guessing you're not using the Rotel for surround sound. I just looked at a photo of the back panel of your sub and you really don't have to worry about whether you can hook it up with whatever you buy. Your sub has a versatile set of inputs--you can plug in a mono LFE RCA interconnect, R-L stereo interconnects, or speaker cables. The Anthem 225 has a pair of preamp-out jacks, so you could use a stereo pair of interconnects to drive your subwoofer. If you were to get a stereo integrated amp *without* pre-outs, you could still connect your sub with speaker cables.

Now on to the speakers. I have recently auditioned a pair of speakers that should be about perfect for your situation. 20x24 is a large room, and many good floorstanders that can fill that space are above your budget. However, the Monitor Audio Silver RX8 is an excellent, well made speaker with a neutral tonal balance, excellent low level detail, and BIG sounding in a modest size and right about at your budget. They retail at $1750/pair (here's a demo pair right at your budget) and are a demure 38" high. I heard these in a ~16x20 room and they were actually a bit much for it. They should be perfect for 20x24. In fact, this double-ported speaker comes with a pair of foam plugs for the ports if you need to dampen the port output to fit the room. That gives you 4 different physical bass damping configurations.

I also listened to the next size down, the RX6, which is slightly smaller and has one less woofer. It's amazing how much more sound Monitor Audio got out of the RX8 with just one more woofer. The RX8 makes the RX6 sound like a compact by comparison--nice sounding in the sweet spot, but not at all room-filling like the RX8. The Absolute Sound noticed the same things about the RX8's clarity, detail, smoothness, tonal balance, dynamics, and room-filling abilities in this review. It was also a TAS Editor's Choice.