Maximising the acoustics of your meeting room

Glyn Chapman

Acoustic Arrangements

Room Acoustics

• Reverberation

• Intelligibility

• Feedback

• Sound System Equalisation

Reflections

Shapes of room

• Worst possible room shape is a cube.

• The next worst is a room where all dimensions are multiples of the height. A pretty horrible example is a room 6m high, 12m wide, and 18m long.

• A good shape would be, say,

6m high, 10m wide and 14m long

Building Construction

• Sound Absorption Coefficient

Example: Painted Brick 0.02 @ 1khzDrape (18oz) 0.48 @ 1khzPleated Drape 0.75 @ 1khz

Full absorption = 1.0 Full reflection = 0.0

Acoustic Treatments

• If it soaks up water, it soaks up sound!

• Carpets, Drapes, Soft Furnishings

• Acoustic Panels

• You can’t fix it in the mix!

Graphic Equalizers

• Removes rooms resonant frequencies

• Increases headroom

• Improves tonality

• Increases intelligibility

How to set your graphic eq• Pink Noise and RTA• Auto EQ products – dbx Driverack• Ringing Out

Sensitive flat response microphone.Flat EQ on mic channel and graphic.Set gain level just below feedback.Increase each band until feedback and reduce by inverse amount.

orIncrease gain until feedback and reduce offending frequency.

Mid Sweep EQ

Loudspeakers

• Placement

• Dispersion

• Point Source ‘v’ Distributed

Other Tools

• Notch Filters

• Feedback Suppressors

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