Need some Amp help - a little new to properly powering speakers

@kosst,

The OP stated that it "sounded much clearer at lower levels." He did not say it played "louder."

The fact of the matter is that a fair comparison of amplifiers requires matched levels.

High efficiency speakers manage greater low-level dynamics for a given volume.  His original post stated that he noticed a lot of "imaging" loss at lower levels. Maybe he was referring to imaging in the true sense of the word, but I'm betting that dynamics is the more appropriate adjective. I've never had an issue with low-level imaging, but all mid-efficiency speakers I've owned struggled to produce decent dynamics under 70db, regardless of the paired amp.

 I know...I know...you'll tell me I've never owned any decent speakers and that I apparently haven't heard the Focal Arias...

You do not need more efficient speakers for more detail. The most detailed speakers may well be Quad electrostats, and they are horribly ineffcient. The Harbeth range is also very detailed, at both high and lowe levels, and they are not particularly efficient either. All that such speakers need is power, and the more the better.

@Helomech, dynamics are the more appropriate adjective. There was some mid range and high range loss, but anything below -35DB on the Yamaha receiver (150 watt @8ohm) (which again, is a $1,999msrp receiver), had a LOT of dynamic loss.  

Then when paired with the Rotel Receiver (100watt @8ohm), the dynamics were more apparent at lower volumes. As the Receiver measures its volume in DB, the Rotel does not (0-100). Around 30, the Rotel receiver brought out more dynamics, and mid ranges that sounded lost with the Yamaha, at what was a much lower volume. 

I'm pretty new to this, but overall after doing some DB sensitivity research and other things, it's pretty safe to say that Polk LSIM707s definitely aren't the most responsive towers on the market. 

However, @Charles1dad, I think I'm gonna give a tube amp with them a shot. Seeing as how I'm new, the experimentation would be fun =). 

@Charles1dad, what tube amp would you recommend in or under the $1000 range? I don't mind buying used audio equipment on Ebay. I do however live in Oklahoma and needless to say....there isn't a whole lot of after market trading here. 

Also, I feel the need to thank everyone who has posted their opinions and thoughts here. 

It has helped broaden my understanding. I also read the research on the 1watt charts that were posted. I then looked at the emotiva amps and as someone posted above, I'd basically be throwing the same power that the Yamaha receiver is already producing which would indeed be a total waste. 

It is much appreciated