Avalon Acoustics Sentinel - Manual (Page 48)

48
Low Frequency Reflections
The first significant reflection of low frequency sound waves comes from two
corners behind the loudspeakers. Another important reflection occurs on the
wall behind the speakers, midway between them. Similarly, low frequency
corner and wall reflections take place at the opposite wall, behind the
listener. These reflections can cause significant distortions in phase and
amplitude, resulting in muddy bass definition, smeared bass transients, and
compressed image definition.
Placing Tube-Traps (available from Acoustic Sciences Corporation) at
selected locations and orientations in the listening room can significantly
control these bass colorations and restore the quickness of bass transients and
the depth of sound stage. We recommend placing floor-to-ceiling columns of
Tube-Traps at all four room corners, at the wall behind the speakers centered
between them, and centered at the wall behind the listener. For listening
rooms with low ceiling height, consider treating the wall-ceiling junctions with
tube traps as well.
Radial orientation of tube traps is critical. The traps at the wall directly behind
the listener, at the wall centered behind the speakers, and at the two corners
behind the listener should be placed with their absorptive sides (the side with
the seam) facing into the room, parallel with the side walls. The traps at the
two corners behind the speakers can be tuned to the listening room, using the
following rough guidelines (see Figure 9.3):
•
seam toward center of room, parallel with back wall: adds depth to
sound stage
•
seam away from center of room, parallel with back wall: adds width
to sound stage
•
seam pointing into corner: sounds livelier, best tonal balance
Figure 9.3 – Tube trap placement and orientation. In this example, the tube
traps are oriented for best overall tonal balance.
Seam facing
into room
Seam facing
into room
Seam facing
into room
Seam facing
into room
Seam facing
into corner
Seam facing
into corner