CAT CAT Amplifiers and Loudspeakers 1 — Questions and Answers
Question 1: What does the damping factor of a power amplifier measure?
- The ratio of load impedance to amplifier output impedance (Correct answer)
- The ratio of input voltage to output voltage
- The thermal dissipation capacity of the output stage
- The maximum continuous power output in watts
Correct answer: The ratio of load impedance to amplifier output impedance
Damping factor is the ratio of the load impedance to the amplifier's output impedance and affects how well the amp controls loudspeaker cone movement.
Question 2: Which loudspeaker enclosure type uses a tuned port to extend low-frequency response?
- Bass reflex (ported) (Correct answer)
- Infinite baffle (sealed)
- Open-back cabinet
- Transmission line
Correct answer: Bass reflex (ported)
A bass reflex enclosure uses a tuned port or slot that resonates to reinforce bass frequencies and extend the low-frequency response.
Question 3: What is the purpose of a crossover network in a multi-way loudspeaker system?
- To divide the audio spectrum and route each band to the appropriate driver (Correct answer)
- To match the amplifier impedance to the speaker load
- To protect the tweeter from DC offset voltage
- To boost the overall sensitivity of the enclosure
Correct answer: To divide the audio spectrum and route each band to the appropriate driver
A crossover network splits the full-range audio signal into frequency bands so that each driver (woofer, mid, tweeter) only receives the range it is designed to reproduce.
Question 4: In a 70-volt distributed speaker system, what component is mounted at each speaker to match impedance?
- A line-matching transformer (Correct answer)
- A passive crossover
- An impedance bridge
- A balanced attenuator pad
Correct answer: A line-matching transformer
Each speaker in a 70V system has a small step-down transformer that converts the high-voltage line to a level the speaker voice coil can handle.
Question 5: A power amplifier is rated at 500 W into 8 Ω. What is the expected output voltage (RMS) at full rated power?
- 63 V (Correct answer)
- 40 V
- 100 V
- 125 V
Correct answer: 63 V
Using V = √(P × R) = √(500 × 8) = √4000 ≈ 63 V RMS.
Question 6: What does 'sensitivity' mean on a loudspeaker specification sheet?
- SPL produced at 1 meter with 1 watt of input power (Correct answer)
- Maximum continuous power handling in watts
- Minimum impedance seen by the amplifier
- Efficiency percentage of acoustic energy conversion
Correct answer: SPL produced at 1 meter with 1 watt of input power
Loudspeaker sensitivity is measured as the sound pressure level (in dB SPL) produced at a distance of 1 meter with 1 watt of input, indicating how efficiently the driver converts power to sound.
CAT CAT Amplifiers and Loudspeakers 1
What does the damping factor of a power amplifier measure?