Hi Crimson Wrath
As has been noted by others the reason you are running into the harshness or brightness in the high frequencies at higher volume levels is your amp clipping. Your Pioneer is rated at 120 watts with one channel driven which is not a lot of total system power. Typically receivers also employ a switching power supply rated to the maximum output specified which means there will be no dynamic headroom above the 120 watts. Dynamic headroom is important to avoid clipping as it can give you useful dynamic capabilities in excess of double the rated power. This is why we use linear power supplies with large (and heavy) toroidal transformers and loads of capacitor storage. When you add together the much higher rated power output of an ADA amplifier and all the dynamic headroom they incorporate you will get the high volume without distortion you are looking for. Murph mentioned the exponential nature of amp power earlier which is an important part of this equation also. Every time you double the amp power you only gain 3dB more in output before clipping; which means big spaces and/or higher desired listening levels require loads of amp power.
The LFR880s would be a good option since you can get the optional ADA1000 DSP/amp combo unit with high level inputs that will work from your Pioneer VSX-919 receiver. Now I am wondering if we shouldn’t have a 5-channel version of this available with a centre channel high level input to allow the entire front of the system to be driven with a high power ADA1000-5 amp just leaving the surrounds to be driven by the receiver amp.
The above said if you do make the jump to the Pioneer Elite you can get the model that incorporates pre-amp outputs and then go to something really big like the ADA1500-5 for the front channels.
