AVIXA CTS-D: Loudspeaker Impedance
& Amplifiers Exam Questions and
Answers
Impedance - Correct Answers -the total opposition to current flow in an AC circuit.
Takes into account resistance and includes forces that oppose changes in current
(inductive reactance) and voltage (capacitive reactance). As frequency changes this
value changes as well.
What loudspeaker circuit wiring is the easiest to troubleshoot - Correct Answers -
Parallel
Series/Parallel Loudspeaker Circuit - Correct Answers -Groups of loudspeakers called
"branches" are wired together in series. Typically, loudspeakers in the same branch
have the same impedance. Each branch is connected to the positive and negative lines
of the amplifier in parallel.
Impedance Meter Tests - Correct Answers --Short Circuits
-Open Loudspeaker Lines
-Transformers that are tapped incorrectly
-Verification of the correct tap values used in the constant voltage system
Best practice in terms of loudspeaker and impedance - Correct Answers -Amplifiers
have a specified impedance that is expected to be connected to their output terminals.
Matching this specified impedance with the loudspeaker load maximizes the energy
transfer from amplifier to loudspeaker to acoustic energy.
First step before installing loud speakers. - Correct Answers -Verify the expected
impedance of the loudspeaker system circuit
Loudspeaker circuit wiring options - Correct Answers -1. Series
2. Parallel
3. Combination Series-Parallel
What loudspeaker circuit wiring is the hardest to troubleshoot - Correct Answers -
Combination Series-Parallel
Series Circuit Impedance Formula - Correct Answers -ZT = Z1 + Z2 + Z3 ...ZN
Where:
, ZT = the total impedance of the loudspeaker circuit
ZN = the impedance of each loudspeaker
Parallel Loudspeaker Circuit - Correct Answers -The positive output of the amplifier
connects to every loudspeaker's positive terminal, and each loudspeaker's negative
terminal connects to the amplifier's negative terminal.
Series Loudspeaker Circuit - Correct Answers -Each loudspeaker's coil is connected to
the next loudspeaker. The power amplifier's positive output terminal connects to the
positive terminal of the first loudspeaker. The last loudspeaker's negative terminal
completes the circuit by connecting to the amplifier's negative terminal
Parallel Circuit Impedance Formula: Loudspeakers with the Same Impedance - Correct
Answers -ZT = Z / N
Where:
ZT = the total impedance of the loudspeaker system.
Z = the impedance of each loudspeaker.
N = the quantity of loudspeakers in the circuit.
If all of the loudspeakers are of the same impedance, the impedance of the loudspeaker
divided by the number of loudspeakers wired in parallel equals the impedance of the
circuit.
Parallel Circuit Impedance Formula: Loudspeakers with Differing Impedance - Correct
Answers -ZT = 1 / ((1/Z1) + (1/Z2) +... (1/ZN))
Where:
Zx = the impedance of each individual loudspeaker
ZT = the total impedance of the loudspeaker circuit
Impedance Measurement Process - Correct Answers -1. disconnect the wires from the
amplifier.
2. Calibrate the meter
-Connect the test leads to the meter.
-Using the three range buttons, select the scale that is appropriate for your expected
value for greatest accuracy.
-Hold the test leads together so the tips are touching, or press and hold the zeroing
button.
-Rotate the calibration knob until the reading indicates "0" (zero).
3. Connect one lead to the each of the wires on the first loudspeaker in the chain.
Polarity is not important.
& Amplifiers Exam Questions and
Answers
Impedance - Correct Answers -the total opposition to current flow in an AC circuit.
Takes into account resistance and includes forces that oppose changes in current
(inductive reactance) and voltage (capacitive reactance). As frequency changes this
value changes as well.
What loudspeaker circuit wiring is the easiest to troubleshoot - Correct Answers -
Parallel
Series/Parallel Loudspeaker Circuit - Correct Answers -Groups of loudspeakers called
"branches" are wired together in series. Typically, loudspeakers in the same branch
have the same impedance. Each branch is connected to the positive and negative lines
of the amplifier in parallel.
Impedance Meter Tests - Correct Answers --Short Circuits
-Open Loudspeaker Lines
-Transformers that are tapped incorrectly
-Verification of the correct tap values used in the constant voltage system
Best practice in terms of loudspeaker and impedance - Correct Answers -Amplifiers
have a specified impedance that is expected to be connected to their output terminals.
Matching this specified impedance with the loudspeaker load maximizes the energy
transfer from amplifier to loudspeaker to acoustic energy.
First step before installing loud speakers. - Correct Answers -Verify the expected
impedance of the loudspeaker system circuit
Loudspeaker circuit wiring options - Correct Answers -1. Series
2. Parallel
3. Combination Series-Parallel
What loudspeaker circuit wiring is the hardest to troubleshoot - Correct Answers -
Combination Series-Parallel
Series Circuit Impedance Formula - Correct Answers -ZT = Z1 + Z2 + Z3 ...ZN
Where:
, ZT = the total impedance of the loudspeaker circuit
ZN = the impedance of each loudspeaker
Parallel Loudspeaker Circuit - Correct Answers -The positive output of the amplifier
connects to every loudspeaker's positive terminal, and each loudspeaker's negative
terminal connects to the amplifier's negative terminal.
Series Loudspeaker Circuit - Correct Answers -Each loudspeaker's coil is connected to
the next loudspeaker. The power amplifier's positive output terminal connects to the
positive terminal of the first loudspeaker. The last loudspeaker's negative terminal
completes the circuit by connecting to the amplifier's negative terminal
Parallel Circuit Impedance Formula: Loudspeakers with the Same Impedance - Correct
Answers -ZT = Z / N
Where:
ZT = the total impedance of the loudspeaker system.
Z = the impedance of each loudspeaker.
N = the quantity of loudspeakers in the circuit.
If all of the loudspeakers are of the same impedance, the impedance of the loudspeaker
divided by the number of loudspeakers wired in parallel equals the impedance of the
circuit.
Parallel Circuit Impedance Formula: Loudspeakers with Differing Impedance - Correct
Answers -ZT = 1 / ((1/Z1) + (1/Z2) +... (1/ZN))
Where:
Zx = the impedance of each individual loudspeaker
ZT = the total impedance of the loudspeaker circuit
Impedance Measurement Process - Correct Answers -1. disconnect the wires from the
amplifier.
2. Calibrate the meter
-Connect the test leads to the meter.
-Using the three range buttons, select the scale that is appropriate for your expected
value for greatest accuracy.
-Hold the test leads together so the tips are touching, or press and hold the zeroing
button.
-Rotate the calibration knob until the reading indicates "0" (zero).
3. Connect one lead to the each of the wires on the first loudspeaker in the chain.
Polarity is not important.
