User Manual

A White Paper Of The Installation Series Loudspeakers
θ L=6 m L=12 m L=24 m
5 0,087 /
4.336 Hz
0,087 /
4.332 Hz
0,087 /
4.331 Hz
10 0,174 /
2.170 Hz
0,174 /
2.168 Hz
0,174 /
2.167 Hz
15 0,261 /
1.449 Hz
0,261 /
1.448 Hz
0,261 /
1.447 Hz
20 0,347 /
1.089 Hz
0,347 /
1.088 Hz
0,347 /
1.088 Hz
Phase difference = 120 degrees
To confirm the validity of our consideration,
we made the following test.
Using the Yamaha SREV1, we created the
phase differences of 90, 120 and 150 degrees at
2 kHz by simulating the impulse response that
has a different inclination of phase
characteristics in the frequency range.
Then we compared the frequency response at
the testing point.
Figure 7 shows the test condition while Figure
8 shows the result.
The testing point is fully apart from the wall.
We use a boundary microphone in order to
avoid the effect of the reflected sound from the
wall and floor.
All the results are standardized by the result
under the condition where θ=0 and no phase
difference.
Both speakers have a 60x40 directivity and the
degree of their side taper is 15 degree.
When there is no phase difference, if θ is 15
degrees or less, the level difference at 2 kHz or
below is within 3 dB. If θ is 25 degrees or less,
the level difference at 1 kHz or below is within
3 dB.
As the phase difference increases, the area
affected by the dip caused by the interference
expands, as well as the dip frequency lowers.
When the phase difference is 90 degrees, if θ is
15 degrees or less, the level difference at 1kHz or
below is within 3 dB.
When the phase difference is 150 degrees, even
if θ is 0 degrees or less, the level difference at
1kHz or below is more than 6 dB. These results
show that, when using more than one speaker,
it is very important to match the phase
characteristics of the speakers in order to get
the same response at any position in the room.
<Figure 7: Test condition>
60ft
0 degree
Boundary Mic.
5 degree
10 degree
<Figure 8: Characteristics in the overlapped area>
Phase 0 degree
-25
-20
-15
-10
-5
0
5
100 1000 10000
Frequency [Hz]
Relative S.P.L. [dB]
deg 5
deg 10
deg 15
deg 20
deg 25
deg 30
Phase
AMP
YAMAHA: SREV1
θ
PC
Smaart
Live
- 6 -