Fundamentals of Audio Production, Chapter 10 1 Fundamentals of Audio Production Chapter Ten: Loudspeakers

Fundamentals of Audio Production, Chapter 10 2 Loudspeakers as transducers The speaker converts electrical energy into physical energyThe speaker converts electrical energy into physical energy Alternating electrical current causes the voice coil to move in relation to a permanent magnetAlternating electrical current causes the voice coil to move in relation to a permanent magnet Movements in the coil are transferred to a diaphragm or cone, which create movements in air moleculesMovements in the coil are transferred to a diaphragm or cone, which create movements in air molecules

Fundamentals of Audio Production, Chapter 10 3 Voice Coil Permanent magnet Voice coil Dust cover

Fundamentals of Audio Production, Chapter 10 4 Elements of the Loudspeaker Voice Coil Permanent Magnet Spider Coil Form Dust Cover

Fundamentals of Audio Production, Chapter 10 5 Elements of the Loudspeaker

Fundamentals of Audio Production, Chapter 10 6 Speaker operation

Fundamentals of Audio Production, Chapter 10 7 Enclosures Speakers lack efficiency in converting electricity into audio energySpeakers lack efficiency in converting electricity into audio energy Placing the speaker inside an enclosure improves its efficiencyPlacing the speaker inside an enclosure improves its efficiency

Fundamentals of Audio Production, Chapter 10 8 Enclosures

9 Compression Drivers Compression drivers operate on the same principle, but are attached to hornsCompression drivers operate on the same principle, but are attached to horns Horns increase the efficiency of the driver by enhancing sound wave propagationHorns increase the efficiency of the driver by enhancing sound wave propagation The result is that horns “sound louder” with the same level of amplificationThe result is that horns “sound louder” with the same level of amplification

Fundamentals of Audio Production, Chapter Compression Drivers Driver Horn Mouth Horn Throat

Fundamentals of Audio Production, Chapter Alternative driver designs Electrostatic driver design

Fundamentals of Audio Production, Chapter Crossover Networks Crossovers separate the signal into component frequencies which are routed to individual driversCrossovers separate the signal into component frequencies which are routed to individual drivers Separating the frequencies allows the drivers to be more efficient and protects them from being overdrivenSeparating the frequencies allows the drivers to be more efficient and protects them from being overdriven

Fundamentals of Audio Production, Chapter Crossover Networks Crossovers may be passive which are internal – inside the speaker enclosureCrossovers may be passive which are internal – inside the speaker enclosure –Passive crossovers have fixed crossover frequencies Crossovers may also be active which are outboard units that are user adjustableCrossovers may also be active which are outboard units that are user adjustable –Active crossovers are used in bi-amplifying or tri-amplifying sound systems

Fundamentals of Audio Production, Chapter Tri-amplified sound system

Fundamentals of Audio Production, Chapter Three and four way systems Tweeters reproduce high frequencies (above 5 KHz)Tweeters reproduce high frequencies (above 5 KHz) Mid-range drivers reproduce middle frequencies (1-2 KHz)Mid-range drivers reproduce middle frequencies (1-2 KHz) Woofers reproduce low frequencies (below 1) KHzWoofers reproduce low frequencies (below 1) KHz Sub-woofers reproduce very low frequencies (below 100 Hz)Sub-woofers reproduce very low frequencies (below 100 Hz)

Fundamentals of Audio Production, Chapter Speaker Placement Studio monitors should be placed equidistant from the listenerStudio monitors should be placed equidistant from the listener

Fundamentals of Audio Production, Chapter Speaker Placement Speaker distances may be described asSpeaker distances may be described as –Far field –Mid field –Near field –Ultra near field

Fundamentals of Audio Production, Chapter Speaker Placement Traditional “side stack” speakers for live sound

Fundamentals of Audio Production, Chapter Speaker Placement “Central Cluster” for live sound

Fundamentals of Audio Production, Chapter Impedance Electrical impedance is the reluctance for alternating current to flow in a voice coilElectrical impedance is the reluctance for alternating current to flow in a voice coil Mechanical impedance is the physical opposition for the speaker cone or diaphragm to moveMechanical impedance is the physical opposition for the speaker cone or diaphragm to move Acoustic radiation impedance refers to how efficiently the speaker moves airAcoustic radiation impedance refers to how efficiently the speaker moves air

Fundamentals of Audio Production, Chapter Speaker impedance must be matched closely to the amplifier’s output impedance to avoid damaging the amplifier, and to increase system efficiency As speaker impedance drops, current flow increases, causing overheating of the amplifier components Impedance