This document discusses how to properly calibrate monitorspeakers. It recommends aiming the speakers towards the listening position and setting an equal distance between the speakers and listener. The optimal speaker height is ear level. Room acoustics like early reflections and wall distance impact sound and should be addressed. Genelec products help correct issues from room interactions to achieve accurate sound reproduction.
5. Standard stereo pair, a virtual sound image
Virtual sound image (in this case
stereo image) is formed
between the loudspeakers.
Precision of the sound image
depends on 3 elements:
1. The quality of audio source
2. The quality of loudspeakers
3. The acoustics in the listening
room
6. Preventing early reflections
Early reflections can be attenuated by:
• Removing or turning reflecting
surfaces
• Adding absorption or diffusion on the
reflecting surfaces
• Moving the speakers
The hard surface can be turned so
that reflection does not hit the listener
7. Loudspeaker layout and aiming
– Aim the loudspeakers towards the
listening position
– Set equal distance from the
loudspeakers to the listening position
– Set correct angles
• Left - Right distance is the same as the
distance from listening position to the
loudspeakers (60 degrees)
Recommendation ITU-R BS.775-1
8. Loudspeaker height
• Loudspeakers optimal height is at the
listener’s ear height , typically around 1.2m
• If unwanted floor reflections occur, try
increasing the monitor height
• If the speakers are set on a higher level, the
tilt-down should be max 15 degrees - to avoid
the displacement of sound image
12. Loudspeaker radiation pattern
Enclosed driver
Omnidirectional radiation Radiation to forward Forward beam width
typically f < 200Hz direction only becomes narrow
typically f > 300 Hz typically f > 10 kHz
13. Wall loading effect
Wall loading increases output level at bass frequencies boomy sound can be corrected by equalization
free half quarter 1/8 space
space space space
Flat +6dB +12dB +18dB
No walls flat response One wall close to Two walls (corner) Three walls close to
the loudspeaker close to the loudspeaker the loudspeaker
15. Recommended wall distance
The minimum distance
allows the bass reflex
port to work properly
The distance produces bass cancellation, causes
loss of bass frequencies in the listening position
16. Back wall cancellation
• Back wall cancellation will cause loss of bass in
the listening position
• Avoid placing the monitors between 1- 2.2 m
from the wall due to back-wall cancellation!
You can easily find the cancellation
frequencies with the Genelec AcoustiTape.
Ordercode MAI-0079.
16
18. Conventional ”square box” design
On axis Gain A
Gain, dB
Conventional Loudspeaker
15 Horiz Gain
Horizontal off axis 30 Horiz Gain
90
45 Horiz Gain
85 60 Horiz Gain
80
75
70
65
60
55
50
10 100 1,000 10,000 100,000
19. Genelec 8000 series
On axis Gain A
Gain, dB Genelec 8050A - Horizontal off axis 15 Horiz Gain
90 30 Horiz Gain
45 Horiz Gain
85 60 Horiz Gain
80
75
70
65
60
55
50
10 100 1,000 10,000 100,000
• Next we will introduce Genelec briefly and take you through some principles in setting up good monitoring
• “Standard stereo pair, as we have here today”
• Early reflections cause: - coloration of sound - blurred sound image
•Here is how to do it, “Triangle where each sides are the equal length”Where to sit for listening in the room, symmetrical set up
In the Monitor set up guide you can read more
Omni directional Low frequency to narrow beam High frequency.
• Low frequenciescontain more energy and act like “flooding water”• Short soundwaves are more directive and have less energyLowest frequency of some sound suorces.
Free space frequency response when the loudspeaker leaves the factory.
Bass tiltBass roll off
1m from the back wall will get about 15 dB down at 85Hz, -3db at 60Hz and 120Hz
AcoustiTape how it shall be used.
• Conventional speaker with a flat front baffle design without the Waveguide• Moving off-axis the frequency frequency becomes uneven and unnatural - e.g. due to edge diffraction
• DCW• MDE Minimum Diffraction Enclosure results much smoother frequency response in both On- and Off-Axis
Genelec DSP MonitorerIn The Genelec DSP loudspeaker systems we can with the AutoCal software control and calibrate the DSP loudspeaker for our room.AutoCal comes whit a Genelec measurement microphone and an interface. The Program can be down loaded from our web site.