Grimm Audio LS1, User Manual, Page: 8 / 62

Positioning
Room Acoustics
Keep in mind that one always hears the loudspeaker plus its acoustic environment.
Although the LS1 has superior acoustical characteristics, positioning it correctly in your
room remains of great importance. Let‘s first have a brief look at room acoustics and then
see how positioning the LS1 influences them.
Roughly speaking there‘s three factors in acoustics that influence the audible perfor-
mance of a loudspeaker: first reflections, low frequency coupling of nearby walls and
room modes (or room resonances). Lateral first reflections influence the stereo image.
Since high frequencies are dominant in acoustic imaging, adding fabric acoustic absorp-
tion like curtains at the reflection spots on the left and right walls helps a lot. Since the
LS1 has a wide baffle, aiming the loudspeaker away from the reflective spot helps too. A
special case is reflections against a vertical obstacle in front of the listener, like a table or
a computer screen, bouncing the sound toward the front wall and from there back to the
listener. In those cases, absorbing the reflection at either the obstacle or the wall cures
the problem. Due to the wide baffle of the LS1, reflections on the wall behind the listener
tend to have more impact than with other loudspeakers. Please consider to add
absorption or sound scattering objects like bookcases against this wall.
First reflections also introduce phase distortion in the early sound if the walls are too
close. Psycho acoustics tells us this effect is important down to 250 Hz. The period of a
250Hz tone is 4ms and sound travels app. 1.4 m in that time. Rules of thumb are there-
fore that you need to have at least 80cm distance from the side walls (1.5 m is better)
and 60cm from the back wall (1.2m is better). The wide baffle of the LS1 makes the
distance to the wall behind them less critical, but if you have the chance, please allow for
some distance.
Next issue is low frequency coupling of nearby walls. Below 250 Hz the LS1 radiates
sound in all directions and sound travelling backwards and sideways reflects against the
walls and adds up to the direct sound. Although the ear is less sensitive to the resulting
phase errors at these low frequencies, the impact on the low frequency energy itself can
be dramatic. A real solution is to apply low frequency absorption behind the loudspeaker
so the reflection is attenuated. Those who cannot afford such measures are invited to
spend some time shifting the speakers back and forth untill the optimal compromise is
found.
Positioning
page 8