CEA Speaker Systems & Amplification 3

Question 1

Line array speaker systems are designed to produce what type of wave front, and what is its key distance advantage?

Accepted Answer

A cylindrical wave front that loses only 3 dB of SPL per doubling of distance

Answer

A spherical wave front that doubles SPL every 6 dB per distance doubling

Answer

An omnidirectional wave front suitable for small club environments

Answer

A flat wave front that maintains constant SPL regardless of distance

Question 2

Four 8-ohm speakers are wired in series. What is the total impedance?

Accepted Answer

32 ohms

Answer

2 ohms

Answer

8 ohms

Answer

16 ohms

Question 3

Why is a limiter placed in a speaker-system signal chain before the power amplifier?

Accepted Answer

To prevent amplifier clipping and protect drivers from excessive or distorted power

Answer

To extend the low-frequency response of the woofer

Answer

To add harmonic warmth to the audio signal

Answer

To increase the signal-to-noise ratio of the system

Question 4

A compression driver used in a high-efficiency PA horn employs which transducer mechanism?

Accepted Answer

Moving-coil (dynamic) with a phase plug

Answer

Electrostatic diaphragm

Answer

Ribbon element

Answer

Piezoelectric crystal element

Question 5

In a properly set gain structure, the amplifier's input sensitivity control should be adjusted so that:

Accepted Answer

The amplifier reaches full rated output exactly when the mixer outputs its maximum clean level

Answer

The amplifier clips just before the mixer's master fader reaches unity

Answer

The amplifier operates at its minimum gain setting to reduce the noise floor

Answer

The amplifier output exceeds the speaker's RMS rating by 6 dB for added headroom

Question 6

How does speaker efficiency differ conceptually from speaker sensitivity?

Accepted Answer

Efficiency is the ratio of acoustic output power to electrical input power; sensitivity is a standardized SPL reading at 1W/1m

Answer

They are identical measurements described with different terminology

Answer

Sensitivity is measured in watts; efficiency is measured in decibels

Answer

Efficiency applies only to subwoofers; sensitivity applies to full-range systems

Question 7

When two identical subwoofers are placed side by side on the floor facing the audience, the primary acoustic result compared to a single subwoofer is:

Accepted Answer

Up to 6 dB more on-axis SPL with narrowed horizontal dispersion

Answer

Exactly 3 dB more SPL with no change in horizontal coverage pattern

Answer

Frequency response extended one full octave lower

Answer

A cardioid polar pattern that reduces bass behind the stage