Dynaudio Air Series manual Acoustics Background Info

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ACOUSTICS - BACKGROUND INFO

At low frequencies a monitor can be considered as to radiate the sound energy in all directions.

This is also called a 4 π radiation.

When placing the monitor close to a solid boundary - for instance a wall - the sound energy that should have been radiated in the direction of the wall instead is radiated into the free half space. Hence the sound pressure is doubled in the half space, which yields +6 dB.

This is also called a 2 π radiation.

Placing the monitor against two boundaries - for instance in a corner limited by two walls - it is now radiating to the quarter space. Now the sound pressure is doubled twice, which yields +12 dB.

This is also called a π radiation.

Placing the monitor against three boundaries - for instance in a corner limited by the floor and two walls - the sound is radiated into 1/8 of the space. Compared to free space, the sound pressure now is increased by 18 dB.

This is also called π/2 radiation.

In practice the placement close to boundaries will influence the frequency range below 125-150 Hz.

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Contents Page Page Important Safety Instructions Voltage Line plug according to standardPage Table of Contents Quick Setup Reference Quick Setup Reference Operational Overview Main DisplayStereo Setup with mono Subs SetupsStereo Setup Stereo Setup with stereo SubsThis illustration shows how to connect a 5.1 digital setup Digital SetupAnalog Setup This illustration shows how to connect a 5.1 analog setupThis illustration shows how to connect a 5.3 Digital setup This illustration shows how to connect a 5.3 Analog setupThis illustration shows how to connect a 6.1 Analog setup Dig/6 MasterAnalog/Digital setup Stereo Setup With Chains on L & ROther Chained Setups Analog connectionsDigital 192 kHz Digital Setup Break IntroductionThis Manual Product ConceptMaster Unit Remote ControlCommon Features Slave & Sub UnitsSlave/Sub Rear Panel Description MasterMaster Unit Analog I/O Optional Digital I/O cardEnter key Cursor UP/DOWN keys AIR DisplayOverload Indication Overload Indication LEDBasic operation in all menus Press Enter to access the Select ModeParameter Description Main DisplaySet Monitor Task Setup MenuSetup External ClockStore LFE channel noteRecall Placing the Monitors OverviewOther situations Close to wall / WallOn the bridge / Console Checking by ear when listening to the signals In phase Checking the placementPhase checking EvaluationEqualizing NextAcoustic level calibration Calibrating Main Monitors CurvesInterchannel calibration CurvePlacing the Subwoofer Low frequency sweeps EvaluationControlling standing waves Checking summing phase cancellationTo Calibrate Checking the CrosspointLFE Gain PhasePhase Introduction PolarityReverberation time AcousticsGood acoustics Sabines formula Membrane absorbers AbsorbersDiffusers Absorbtion or diffusion ? Resonance absorbersBackground Info Acoustics Standing WavesRoom modes Axial Tangential RadialHow to prohibit standing waves How does the standing waves influence the sound field?Acoustics Background Info Comb Filtering Or + Dip frequenciesRear wall cancellation Subwoofer Background Info SubwooferCross-overs Subwoofer & LFE Channel Background InfoLFE Channel Low Pass LFE GainCinema setup Delaying Monitors LINE-UP & CalibrationAcoustic summation of audio signals Calibration of 5.1 in an ITU-775 arrangement How to measure the sound pressure?LINE-UP & Calibration Background Info Introduction Remote Control FeaturesAIR Remote REF Level 1-3 keys Preset 1/3 and 2/4 keysVolume potentiometer Shift keyAIR Soft Navigating AIR SoftMain ToolsPreset List NetworkSystem Setup Calibrate AIR-Base Chained monitorsGlobal Parameters Reset ProceduresMiscellaneous Local ParametersAES/EBU Standard cables CablesTC Link Standard Cat-5 cables Serial to Cat-5 cableAIR 6 & AIR 15 Master and Slave AIR 20 & AIR 25 Master and SlaveAIR-Base-1 & AIR-Base-2 AIR BaseAIR Remote specs Room & DistanceGeneral for all Products Delay in System & Error Messages ETC Error messages etcAIR AIR-Base Certificate of ConformityCertificate Of Conformity Preset List # Name