An electro-mechanical device for converting varying audio voltages into corresponding sound waves.
Dynamic
Amplifier sends alternating voltages to a voice coil that moves within a magnetic field. Magnet that surrounds voice coil moves voice coil and paper or synthetic diaphragm which creates sound waves.
Sizes
Damage Control
Excessive heat in voice coil due to volume or low frequencies.
Tweeters particularly susceptible.
Fuses in house wiring.Excessive excursions (volume)
Bottoming - clacking of voice coil hitting back plate
Rattle - voice coil pops out of slot and does not properly reenter.
No sound - coil jammed in slot.
Characteristics of Dynamic Loudspeaker
Higher fidelity
"Sweeter" sound
Compression Drivers
Thin metal diaphragm that compresses air into a pressure chamber that leads to a horn-type radiator.
Excellent for high-frequencies.
Less capable of recreating low frequencies.
More volume
More directionality
Enclosures
Phasing
All sound waves should have same exiting point from the speaker so acoustic waves are in sincAcoustic Demands
Speakers are designed for assumed acoustic environment
Backwave Considerations
Infinite Baffle
Cabinet Proportions
Depth = A
Width = A x 1.73
Height = A x 2.46
Lower frequencies boosted when large sealed enclosure such as an adjoining room is used.
Bass Reflex (or Vented Box)
Open port for bass backwave to be added to resonant frequency. (Only very low frequencies move easily around corners).
Folded Horn
Baffles used to lengthen the backwave path.
Crossover Networks
Separates frequencies into overlapping ranges that are routed to speaker designed best for that particular range.
JBL Control 1 Pro Loudspeaker
- Passive Crossover
Frequency Range: 80 Hz to 20 kHz
Power Capacity: 150 W
Crossover Frequency: 4.2 kHz
Active Crossover
Compressed Driver Domeo Tweeter: 3-16 kHz
Compressed Driver Horn Midrange: 200 Hz-5 kHz
Folded Horn Woofer: 16-300 Hz
OAP T-102
Frequency Range: 78 Hz - 16 kHz
Power Capacity: 300 W
Bass-reflex enclosure
38Hz-150Hz
600 watts
Angle at which there is no more than 50% drop in Db
Higher frequencies are more directional than low frequencies
Cellular cones may limit beaming.
Impedance
Electrical resistance speaker presents to amplifier (16, 8, or 4 ohms).
Divides by half each time an additional speaker is introduced in parallel.
Frequency Response
Range of frequencies particular speaker reproduces. Generally linear, unless
more of particular frequency is desired.
Nominal Power Handling
Maximum power (measured in watts) that can be handled over long period of
time without damage to the speaker.
System Configurations
