First, double-check to make sure that your Marantz settings are correctly configured for 2.0 (stereo) speaker output.
Main speaker setting should be: Front speakers = Large
All other speakers = Off.
Also experiment with different speaker placements to ensure that you're not having bass cancellation effects from the room (less likely).
Although the NHT's are inefficient speakers, the Marantz at > 100 Watts/ch should be powerful enough to drive them in a reasonably-sized room.
That said, these NHT's are designed to benefit from bi-amplification, if for nothing more than to fine-tune the bass response.
Maybe others can offer experiences on using other channels of the Marantz for bass amplification in a stereo configuration. I'm inclined to think that using the center channel to power the bass will not give you what you are looking for here, but other Agoners will have had direct experience with this.
Sandstone
Main speaker setting should be: Front speakers = Large
All other speakers = Off.
Also experiment with different speaker placements to ensure that you're not having bass cancellation effects from the room (less likely).
Although the NHT's are inefficient speakers, the Marantz at > 100 Watts/ch should be powerful enough to drive them in a reasonably-sized room.
That said, these NHT's are designed to benefit from bi-amplification, if for nothing more than to fine-tune the bass response.
Maybe others can offer experiences on using other channels of the Marantz for bass amplification in a stereo configuration. I'm inclined to think that using the center channel to power the bass will not give you what you are looking for here, but other Agoners will have had direct experience with this.
Sandstone