Any Benefit to Bi-Amping Bookshelf Speakers?


I recently upgraded an old receiver (pre-HDMI old) to a Marantz SR7012 for an existing 5.1 system in the living room. Mostly just wanted to add functionality and get rid of all the legacy connectors but it sounds quite a bit improved as well. I added a zone 2 on the patio, but that still leaves me with 2 of the 9 amp channels without a home and the improvement so far has me wondering what might be possible. The wife won’t let me tear up the ceiling for Atmos until after we remodel the kitchen so don’t bother with that suggestion :). 

The front R & L speakers are B&W 685s2. Max power handling per the specs is 100W but they are bi-amp capable. Would there be any advantage to bi-amping a smallish bookshelf speaker like this with minimal power handling capability (the receiver already puts out >100W/channel) or would I only be risking blowing them up or messing up the integration with the center and surrounds by doubling down on power? I have the wires run through the walls for aesthetic reasons so I don’t want to bother pulling new wires if there’s not any expected benefit. Use is about 80/20 TV/Music so any benefits to 2-channel experience would be worth noting as well.

Thanks!
ethos123

It really depends on how the Marantz handles "bi-amping".  If the Marantz will send the same signal on both bi-amp outputs, then you should be fine with experimentation.  However, I have seen some receivers that handle bi-amp in a weird way.  They will use an active "comparator" circuit to determine the frequencies that the "bass" bi-amp output is actually using.  Then they will subtract those frequencies from the signal and output the "difference" on the high bi-amp output.  The result here is significant loss of sound quality.

In either way, I don't think you'll be getting much benefit because both bi-amp outputs will share the same power supply in your Marantz.  I have heard others that report an increase in sound quality.  If your speaker wire is all run through walls, then it may not be worth the effort.

Only if an active x-over is used to split the signal between low and high frequencies. One amp then gets only the low frequencies and the other amp the upper range signal.