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43 Cards in this Set
- Front
- Back
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What is the purpose of the speaker enclosure?
2 reasons... |
To stop natural elements (wind) from pushing the rear of the driver causing extra movement of the voice coil. To stop resonating frequencies behind the driver from escaping to the front.
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What is the purpose of the port on the speaker enclosure?
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To reinforce the low end frequencies.
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What are two determining factors in the placement and size of the port?
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Diameter will allow certain resonating frequencies to escape depending on the wavelength.
Length of the tube will add slight time delay to avoid phase cancelation. |
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What are two features of the Speaker Horn.
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They are efficient due to natural compression in the throat.
They are highly driectional. |
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What is the dynamic range and what determines it?
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Difference in dB between noise floor and system maximum output before distortion.
Determined by the system. |
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What is headroom and what determines it?
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Difference in dB between the softest and loudest mix before distortion.
Determined by the engineer |
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What is white noise?
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Equal energy per Hz
3db increase per octave Sound of current (electron movement through the system) |
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What is pink noise?
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Equal energy per octave
White noise with 3 dB rolloff filter |
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What is popcorn noise?
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Caused by dust and debris inside connectors.
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What is HD?
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Harmonic Distortion (happens on weak passive systems) requires excessive EQing to correct
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What is the speed of sound?
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1130 FPS
761 MPH |
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What is the speed of light?
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186,242 miles per second
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What is another name for a woofer?
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Direct radiator
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What is the stationary magnetic field?
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The result of the voice coil being surrounded by the magnet.
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What is the secondary magnetic field?
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The result of the amplifier output though the voice coil.
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What causes the actual transduction in a speaker system?
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The interaction of both the stationary and the secondary magnetic field.
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What is the frequency response?
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Any component's ability to produce an output signal with the same freq range as the input signal.
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What is the State of tolerance?
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Amplifier or speakers ability to produce the intended freq range within a margin of error.
Speaker +/- 3dB Amp +/- 1 dB |
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What is Power Handling and how is it measured?
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Measured in watts and is judged based upon three ratings, Continuous Rating, Peak Rating, and Program Rating.
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What is the Continuous rating?
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Low Level Signal sent to the speaker for a long period of time to determine how well the voice coil can handle the heat.
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What is the Peak rating?
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A very loud signal sent to the speaker for no more than a tenth of a second.
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What is the Program rating?
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Represents the actual program including silence.
It is used to match the power to the amplifier. |
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What is the sensitivity?
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a test of a speakers ability to reproduce and project low level signal at a distance.
A) 1 watt @ 1 meter B)1 watt @ 4 ft C) 1 milliwatt @ 30ft. |
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What is impedance?
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Total opposition to the flow of electrons in an A/C circuit. It equals Resistance + Reactance.
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What are the three types of system impedance?
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Source Impedance: Impedance of the Amp.(never changes)
Load Impedance: Impedance of the speaker. (always changes) Nominal Impedance: lowest amount of impedance the speaker presents to the amp. The load impedance should always be more than the source or disaster will strike. |
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What is the voice coil?
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Flat cable wrapped around the former
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What is the former?
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Chemically treated paper to make it heat resistant.
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What does the magnet in a speaker look like?
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A donut shape fitted top and bottom with 2 steel plates.
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What is the pole piece?
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A steel rod inserted into the donut shaped magnet.
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What is the gap?
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Space between the pole piece and the magnet that is home for the voice coil.
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What is the dome?
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The dust cover for the gap.
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What is the spider?
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Attaches voice coil to the cone and dome.
Allows easy suspension of the voice coil. |
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What is the cone?
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Attaches to the basket.
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What is the basket?
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Actual physical shape of the driver.
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Active Crossover Characteristics
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Pre the Amplifier
Works on very low (line) level signal Cost effective No Insertion loss |
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Passive Crossover Charachteristics
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Post the Amplifier
Works on a very high level signal A ton of insertion loss |
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What is insertion loss?
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it is the loss of no more than 1dB of signal due to the heat of the fundamental electronic components in a passive crossover. 1dB=21Watts
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How far from the flat range is a cutoff frequency always at?
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-3dB
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What is the slope?and how is it measured?
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The rate at which the frequency to its own driver will start to gradually fall after the cut off frequency point.
It is measured by db/octave |
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What is a 1st order crossover?
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6dB/ Oct (consumer)
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What is a 2nd order crossover?
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12dB/ Oct
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What is a 3rd order crossover?
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18dB/ Oct (Semi Pro)
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What is a 4th order crossover?
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24dB/ Oct (Pro)
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