VANDERSTEEN 3A - THIRD DIMENSIONS PLACEMENT

Several factors influence how speakers interface
with a room other than the room’s basic dimensions so
it is possible that none of the placement options on the
wall you initially place the speakers on will sound quite
right. The sound may have too much or too little bass
or be too forward or too withdrawn. If you are unable to
achieve satisfactory sound with the speakers placed on
one wall, try placing the speakers on another wall of
the room. Even in a rectangular room, the speakers will
interface differently with the room depending upon
which of the four walls they are placed. In some rooms
the speakers will sound best placed on a short wall
while in other rooms the speakers will work better
placed on a long wall.
Third Dimensions Placement
A placement method that provides some unique
effects is to place each speaker on the thirds of the
room measurements and the listening position on the
third of the length. The speakers are placed one third
the length of the room from the wall behind them and
one third the width of the room from the walls along
side them. The listening position is then placed one
third the length of the room from the wall behind it.
In our 14 by 18 foot example room, the thirds are
72 inches in the long dimension and 56 inches in the
short dimension. The intersections of these measure¬
ments are used for third dimensions placement. In addi¬
tion, the listening position is placed 72 inches from the
rear wall of the room.
r
Listening
Position
t
56
56
72 72
Both speakers should be tried up to two inches
ahead and behind the intersections to determine if this
improves the sound. Both speakers should be moved
the same amount forward or backward.
Third dimensions placement reduces the interac¬
tion of the speakers with the room to an absolute mini¬
mum, but can create aesthetic or room function
problems due to the speakers and listening position
being so far out into the room. (The lower the odd num¬
ber used to divide the room dimensions the lower the
interaction between the speakers and the room.
Acoustical Center
The Model 3A's acoustical center is the physical
center of the loudspeaker. In a perfect rectangular
room with absolutely rigid walls and no doors or win¬
dows, the acoustical center of the loudspeaker would
be placed exactly at the point where the two dimen¬
sions intersect to realize the full benefits of odd dimen¬
sions or third dimensions placement. In a real room,
the actual best placement may vary from the intersec¬
tion by as much as two inches or so. Fine-tuning the
placement by moving the speakers a couple of inches
off the odd dimension intersections takes these real
world conditions into account.
No placement should be used that would place the
acoustical center of the loudspeaker the same distance
from the rear and side walls. The measurement from
the center of the loudspeaker to the two walls should
differ by at least two inches. If any of the odd dimen¬
sion intersections are within two inches of the same dis¬
tance from both the side and rear wall, those
intersections should not be used.
Speaker Toe-in
The degree of toe-in can affect the imaging and
response characteristics of the speakers. In most
rooms, the speakers will sound best facing straight
ahead or slightly toed-in. Speakers that are placed
close to the side walls or in rooms with very reflective
side walls may require additional toe-in to avoid a con¬
fused image and/or a forward midrange and treble.
If the speakers need an excessive amount of toe-
in to image properly or achieve good center fill, there
may be a problem with the set-up or connection of the
speakers or some part of the system may not be
functioning as intended. To determine why the
speakers require excessive toe-in, check all your
speaker wire connections for correct phase and verify
that the electrical components in the system are con¬
nected and functioning properly.
Acoustic Treatments
If the speakers are close to the side walls and you
hear a brightness in the midrange/treble or a problem
with the imaging that toeing-in the speakers does not
help, some sound absorbent material should be
g
Model 3A Operation Manual