Magnepan MG 3.6 - Manual (Page 9)

9. ROOM ACOUSTICS
Magneplanars, like other bipolar speakers, usually sound best with a moderately
reflective surface behind the speakers. In situations where the speakers must be
placed closer than 2 feet from the back wall, a heavy damping material directly behind
the speakers is advised; however, it should not cover the entire wall.
Damping material in other parts of the room is a matter of trial and error. A word of
caution-when audiophiles discover the effectiveness of damping material, they
sometimes overdo it (on the premise that if a little is good, more is better). Before you
make a permanent change to your room, experiment with the positioning of the
damping material. Usually a portion of one or two parallel walls should have some
damping.
An overdamped room will provide very precise imaging, but you will have a reduced
sense of ambience (less reverberation, spaciousness). An underdamped room may
heighten the illusion of being in a concert hall, but the imaging will seem imprecise with
all the instruments mixed together. Moderation is the word.
10. OPTIONAL RIBBON TWEETER ATTENUATION
There are two principal reasons for needing to attenuate the Magneplanar Ribbon
Tweeter:
A. Recordings, typically in the "pop" or "rock" vein, often exhibit a pronounced rise
in the treble region.
B. The Magneplanar Ribbon Tweeter is very efficient in its total "energy
dispersion." If the surrounding walls are exceptionally reflective, the overall
perceived acoustical balance will be tipped towards a "hot" high end.
Attenuation is performed through insertion of a simple non-inductive resistor in series
with the tweeter.
There are inputs provided on the connector plate of each speaker for insertion of a
resistor. To insert a resistor, simply loosen the Alien screws, remove the jumper, insert
the resistor, and tighten the screws.
The pair of 1 ohm non-inductive resistors provided will attenuate the tweeter
approximately 1-2dB. Other values are available from your Magneplanar dealer.