Grimm Audio LS1, User Manual, Page: 11 / 62

2. The reflection of the left loudspeakers‘ sound to the left wall and vice versa becomes
attenuated a bit. Since this reflection path is usually relatively short, it needs to be
attenuated to not interfere with the stereo image. An easy trick to check if this reflection
is too loud is to listen to a mono sound on one loudspeaker only. Close your eyes and
point in the direction of the sound. Now open your eyes again and look at your finger. If
it is pointing towards the center of the loudspeaker everything is fine. If you point a little
bit off-center in the direction of the wall, the reflection is too loud. If turning the LS1‘s
toe-in does not cure the problem, you will need to apply acoustic absorption at the reflec-
tive spots. Mark that by turning the left LS1 like this, its reflection to the right wall will
become louder. Usually this is not a problem because this reflection comes later. Psycho
acoustics says it can even help to extract the ‚ambience‘ information from the recording.
3. It offers a lower distortion. All drivers suffer from a distortion called ‚cone break up‘.
The Seas woofer we selected has a very high break up frequency of 4 kHz. This is far
above the cross-over frequency of 1.5 kHz so the in band sound is not affected by it.
A loudspeaker however is never free of distortion. The third harmonic of 1kHz is at 4 kHz
and this distortion component will be amplified a bit by the cone break up. Since 4 kHz is
a very high frequency for a large woofer, it is radiated as a narrow beam. We measured a
significant drop in distortion around 4 kHz at 15 degrees off-axis, compared to the already
very good on-axis performance.
In about 20% of the rooms, the classic setup with the LS1‘s facing the listener still sounds
better. This is usually the case in fairly large rooms or in rooms with acoustics that are so
well balanced between left and right that a disturbance of that sounds less good. Please
accept this as an invitation to experiment and listen in your own environment.
Once you have decided on which of the two setups sounds best, please run the LS1 remo-
te software and set the „Toe-in angle‘ in the preferences to either 45 degrees or 30 de-
grees. This applies a small correction to the high end, making sure the frequency
response is linear at the listening position.
page 11
Positioning
Positioning