Magneplanar Listening Comparison 1.7 vs. 3.7 Speakers

the big space you can see on the RH side extends into a kitchen - so the room is about 30 ft wide at the speakers; but is about 12 ft wide at the listening position (not counting the cavity in the chimney created by the firebox - the smney stack itself must act like a port (!))

Wendell at Magnepan says the 3.7 is acoustically SMALLER than the 1.7, even tho it is physically larger (different design internally)

Did Wendell elaborate on that term ? How did he describe that one ?

Are you planning to setup against the short or long wall?

On the short wall.  The pic shows where they would go - on either side of the TV just like the 1.5QRs.

I asked Wendell if the internal design differences were the reason the 3.7 was acoustically smaller than the 1.7 and he said yes.  The stmt may also be on their web site.

What does "acoustically smaller" mean?