Some receiver don't work well with some speakers and vice versa. One of the reasons for this is that amplifiers tend to have a "sound signature" or put more simply they tend to not be perfectly flat across the whole frequency band and produce the same amount of detail and even the same amount of power over the whole frequency band. And of course speakers are the same but to an even worse degree. Onkyo amps are somewhat lower frequency dominant similiar to harman kardon,and your speakers are small and have no bass to speak of but a detailed top end-while the onkyo's have a somewhat smooth sounding midrange and slightly rolled off top end. SO you either need to get speakers with a bigger woofer or a new receiver. my favorite speakers at the moment are cerwin vega-i recently made the mistake of buying one of these "secret deal" speakers that seemd great on paper (actually the are the same as the current emp floorstanders that this site is hyping but with different midrange and tweeter)-bass is lumpy and not detailed and midrange and treble are ok but not super duper at all. If you need smaller speakers I would recommend ascend acoustics-i recently bought some and although they are also a little rolled off on top they sounded best when i used them with my onkyo 2 ch recent model receiver. if you're going for larger speakers I really recommend the cerwin vega ve series floorstanders which sell for $350 online from A1. As a reference I have also used B&W,monitor audio,wharfedale,and some others as well-I like all those but in my experience what is most satisfying for most people in most situations is a speaker that is detailed and has good bass(tight bass that has detail and a decent amount of depth). Most speakers don't use a big enough or powerful enough woofer to provide what I call good bass-that doesn't mean they are all bad just that you will get varying levels of bass quality-for example wharfedale is pretty good but not quite as tight or detailed as cerwin vega (and wharfedales sound overly smooth with some amps like denons in my experience and also don't always work well with every amp and the are somewhat dark sounding speakers-although that was just the sp-87 model I used)-monitor audio's are good but unless you get the expensive big floorstanders you're not going to get tons of bass and they have a minor "metal" sound from the metal drivers (it's minor though) and they are very open sounding-really the only thing against them is price and not being perfectly even sounding as they focus more on the midrange imo.And B&W's I have a pair of older one's (10years old lowest model but I've heard many more)-they are well made speakers with an even sound and great midrange detail but they don't "rock" as well as other speakers imo (like cerwin vegas). So-trust me you will be very happy with either ascend sp's (and I have the "monitor's but I would suggest the lowest model because they probably have a bit more bass and unless you are a major audio nut you don't need the "precision" of the monitors (I actually wish I had purchased the lower model) because the monitors do not have enough bass for me-I have heard the montitors I purchased have more detail though so it really comes down to deciding on how much you want to spend and what you're looking for in sound-just keep in mind that for your large listening space you might want a tiny bump in bass from the extra woofer space in the begining model. And if you want to make sure you have enough bass and your budget is bigger buy the cerin vega ve series 12in woofer model (I don't like horn speakers so I would not recommend cerwin vega horn speakers btw-although in a large space they could definitely send the sound around which might be good if you need to send the sound to the other end of the room). If you decide to change your amp instead I would suggest pioneer or maybe yamaha (yamaha is my favorite receiver,although marantz is a little more "high end" sounding and denon also sounds good but i worry about denon and marantz reliability right or wrong-and that may be wrong especially if you buy an extended warranty or whatever)-denon would probably sound good with your energys-pioneer would sound exciting with the energys,marantz would give lots of details--in your case because of your big room I think your money is best spent on new speakers but if you want a different receiver instead your best bet would be denon or marantz (marantz sounds better but denon might have a little more oomph and bass for the equivelent priced model)-yamaha may actually be the easiest choice because they're amps are powerful,exciting,and detailed-the just don't have the "high end" sound of the marantz or to a lesser degree the denon.And pioneer would be a good choice if you want an easy to set up and use receiver with a dynamic sound (but it won't be quite as loud or as good sounding as they other 3 IMO)-although the entry level pioneer I heard last year had an exciting and musical sound -although I tend to like the yamaha ever so slightly smoother sound-but you do lose some upper end detail to the pioneer. However I like the sound of marantz amps as good and maybe better than yamaha,but i don't like hot running amps and am very picky so i lean toward cooler running amps like marantz or maybe the midrange yamahas and I think denon still makes cool amps.the onkyo will sound great with the ascend's or the cerwins I guarantee it (the ascends may actually sound a little better,but the cerwins will give you a much louder (in a good way) sound and will sound maybe a touch more "open" but will lose just a touch of the subtelty of the ascends). I think the cerwins are actually the best deal but if subtelty and speaker size is important to you ascends are a great choice. Onkyo's do sound really good in my experience probably just as good if not better in some instances than yamaha-I do believe marantz and maybe denon make the best sounding amps but unless you were to upgrade your speakers to big monitor audio's or something I don't think the difference would necessarilly be that noticeable and in fact if you just want a good sounding system the onkyo will sound fine to great with the proper speakers like the ones I've mentioned.
