Why you must calibrate your Audio Monitor speakers and how to do it

Post on 20-May-2015

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Transcript of Why you must calibrate your Audio Monitor speakers and how to do it

Why you must calibrate your Monitorspeakersand how to do it

Finland:

- North of Europe

- Population 5,4 Mil.

- Iisalmi 400 km from the Arctic Circle

Helsinki

Kuopio

Helsinki

Iisalmi

Kuopio

Arctic Circle

• Genelec has been manufacturing active loudspeakers in Finland for almost 35 years

Setting up the monitors

Standard stereo pair, a virtual sound image

Virtual sound image (in this case stereo image) is formedbetween 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

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

absorbing surface attenuates

the reflected sound level

The hard surface can be turned sothat reflection does not hit the listener

refle

ctio

n

reflection

direct sound

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

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

height H

height 1,2 m

Floor level distance D

Listener

Max 15 degrees

Loudspeaker distance, choosing the right monitor

This information is availableon web site www. genelec.comand in the Monitor Setup Guidehandout

Loudspeaker in a room

Loudspeaker radiation pattern

Enclosed driver

Omnidirectional radiationtypically f < 200Hz

Radiation to forward direction onlytypically f > 300 Hz

Forward beam width becomes narrowtypically f > 10 kHz

Flat +6dB +18dB+12dB

Wall loading effect

Wall loading increases output level at bass frequencies boomy sound can be corrected by equalization

No walls flat response One wall close tothe loudspeaker

Two walls (corner)close to the loudspeaker

Three walls close tothe loudspeaker

freespace

halfspace

quarterspace

1/8 space

Compensation of the wall loading

Bass Tilt-6dB

Recommended wall distance

The minimum distance allows the bass reflex port to work properly

The distance produces bass cancellation, causesloss of bass frequencies in the listening position

Back wall cancellation

16

• 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.

Genelec Directivity Control Waveguide, DCW

Conventional ”square box” design

Conventional LoudspeakerHorizontal off axis

50

55

60

65

70

75

80

85

90

10 100 1,000 10,000 100,000

Gain, dBOn axis Gain A

15 Horiz Gain

30 Horiz Gain

45 Horiz Gain

60 Horiz Gain

Genelec 8000 series

Genelec 8050A - Horizontal off axis

50

55

60

65

70

75

80

85

90

10 100 1,000 10,000 100,000

Gain, dBOn axis Gain A

15 Horiz Gain

30 Horiz Gain

45 Horiz Gain

60 Horiz Gain

Genelec DSP products - solutions to a perfect sound

Genelec Loudspeaker Manager -

automated calibration system

• Even problematic rooms can become usable!!

Genelec DSP monitoring loudspeakers

8260Acoaxial three-way

8250A8240A8130A 1238CF

Supporting DSP subwoofers

7260A 7270A 7271ASE7261A