Suggestions for bookshelf speakers that have great dynamics, budget of $500 used.


So I really do not know where to start with bookshelf speakers as not been in the market for any for ever it seems.
This is for a second system where a pair of Monitor Audio Silver 3i are currently doing duty.
Room is largish and open but ultimate sq is not the aim as it is occasional use only, but when I do fire this rig up I usually like to play fairly loud.
Sources are many, fm radio, cassette tape, vinyl and streaming.
I have plenty of horses to feed them so even inefficient models can be considered.
Prefer to buy used as big savings to be had obviously and already broken in.
So suggestions around a maximum price break of $500 used.
Thank you in advance.
128x128uberwaltz
You might be able to find a dealer willing to discount some B&W 607s. An industry typical 15% discount would bring their price to $595. Saving just a bit longer to step up to these from the typical ~$400 offerings would be a good move IMO. The older 600 series was quite dynamic and some reviews claim the new 607s are as well. 

You could probably audition 20 other brands and not find any more dynamic than Epos or B&W. One exception might be the new Klipsch RP-600M. I haven't heard them yet but many are raving about their dynamics. However, my presumption is their midrange isn't as refined as some of the British brands. 



Anybody got first hand experience of Revel?
Looking at a pair of M20 CW stands for a fair price.
I have seen Dynaudio Focus 140s go for around 500. If you have plenty of horses as you say they will be really good for that price. 
Wharfedale 10.1 or 225 models are pretty decent and much better than their price might suggest.