Bi-amp them with an active crossover on the bottom it really opens up the NHT's. On the high end of your range I used an EAD Powermaster 2000 5 channel (400watts x5) to biamp the NHT through an active crossover (actually my EAD Signature processor) and used the spare channel for the center Aerial Center Channel! Amazing results and a more liquid top end then the Aragon suggested above (Aragon would work nice for the bottom since they are a real workhorse).
If I remember correctly the bottom was crossed over at 100hz.
Chris
If I remember correctly the bottom was crossed over at 100hz.
Chris