WHAT ARE THE 3 PRIMARY FACTORS DETERMINING POWER LOSS IN SPEAKER
CABLE RUNS? |
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| NAME 3 ELEMENTS THAT HAVE THE GREATEST EFFECT ON SYSTEM DESIGN? |
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| NAME 3 TYPES OF SPEECH INTELIGIBILITY MEASUREMENTS? |
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%Alcons
Speech Transmission Index
Clarity Ratio |
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| WHAT IS THE NAME USED TO DECRIBE UNITS OF ABSORBTION? |
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| DEFINE CRITICAL DISTANCE. |
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| The distance from the source where the reverberant and direct sound field are equal in level |
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| HOW DOES A TEMPERATURE LAPSE AFFECT SOUND? |
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| During the day, the air temperature is warm close to the ground. This temperature decreases as you increase height. The sound bends toward the sky. |
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| HOW DOES A TEMPERATURE INVERSION AFFECT SOUND? |
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| During the night, the air temperature is lower closest to the ground and increase with height. The sound bends toward the ground. |
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| WHAT 2 ELEMENTS ARE AFFECTED BY WIND WHEN DOING OUTDOOR SHOWS? |
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Sound upwind is refracted and attenuated
Sound downwind propagates consistently with it’s speed and frequency slightly altered |
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| WHAT IS THE IMPORTANCE OF A “PHON”? |
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| The phon allows us to account for the frequency dependent nature of the human hearing |
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| WHAT IS PURPOSE OF “A WEIGHTING” ON AN SPL METER? |
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| This contour is designed to approximate the ear at the 40phon level. This weighting is used to measure ambient sound levels. |
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| WHAT IS PURPOSE OF “Z WEIGHTING” ON AN SPL METER? |
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| WHAT IS PURPOSE OF “C WEIGHTING” ON AN SPL METER? |
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This contour approximates the ear’s response at very high sound levels.
Often used to measure traffic noise |
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| WHAT IS THE RECOMMENDED SPL METER WEIGHTING AND RESPONSE TIME? WHY? |
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A weighted slow – correlates with most standard exposure limitation charts.
A weighted slow – also recommended because it focuses attention on the frequencies that sound the loudest and are vital for communication. |
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NAME SOME COMMONLY USED SPEAKER CABLE CONNECTORS USED BY
PROFESSIONAL SOUND COMPANIES (MANUFACTURER AND MODEL). |
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NL-4/NL – 8
EP/AP 4,6,8
Power – NEMA 4-pin |
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| WHAT DOES THE 5% RULE STATE? |
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| Cable resistance should never exceed 5% of load resistance. |
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| WHAT IS “DAMPING FACTOR”? |
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| Damping factor is a numerical indication of how well an amplifier can “control” a loudspeaker’s cone motion |
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| LIVE AUDIO SYSTEMS ARE OPTIMIZED FOR… |
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| PROGRAM SOURCES VARY IN _________, ____________ AND ______________. |
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| NAME THE 3 TYPES OF PROGRAM SOURCES. |
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Microphones
Instruments
Playback |
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| WHAT IS A MIXER’S MAIN JOB WITH REGARD TO PROGRAM SOURCES? |
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| To scale mic level signals to line level (+4dBu) |
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| WHAT ARE 3 MAIN TYPES OF SIGNAL PROCESSING? |
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| WHERE DO WE USE “MATCHED” OR “TERMINATED” INTERFACE? |
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Wireless antenna systems
Video systems |
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IN A ___________ AUDIO CIRCUIT, IT IS BENEFICIAL TO HAVE THE LOAD IMPEDANCE
__ TIMES THE SOURCE IMPEDANCE TO INSURE EFFICIENT ________TRANSFER FROM
DEVICE TO DEVICE. |
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| WHY CAN’T WE “Y” 2 OUTPUTS TO AN INPUT? |
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Outputs will both try to drive each other’s low impedance causing high current to develop
Outputs are low impedance and meant to drive the higher impedance of the input |
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| LOUDNESS AND POWER RELATE TO THE ___ OF THE SIGNAL. |
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| HARMONIC DISTORTION IS CAUSED BY _________. |
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| WHY IS MONITORING THE PEAKS OF SIGNAL IMPORTANT? |
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| WHY IS MONITORING THE RMS OF SIGNAL IMPORTANT? |
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| Helps avoid loudspeaker damage |
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| The time it takes for a meter to respond to a signal aka Meter Ballistics |
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| WHAT IS THE DIFFERENCE BETWEEN A “QUASI-PPM AND A TPPM? |
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A quasi-PPM has a 5-10ms integration time
A quasi-PPM will often read 8-10 dB lower than a TPPM
A true PPM (TPPM) has instant ballistics that read out any short term peaks. |
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| WHAT IS THE MAIN DRAWBACK OF USING A PPM? |
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| A PPM cannot monitor loudness or RMS |
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| 0 DBFS CAN BE REFERENCED TO A ________ OR A ________ WAVE. |
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| WHEN WOULD A TRUE PEAK PROGRAM METER BE USEFUL? |
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| When recording to avoid short term peaks that would cause unwanted harmonic distortion |
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| WHAT IS THE RESPONSE OR INTEGRATION TIME OF A VU METER? |
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| HOW MANY VOLTS DOES 0VU EQUAL? |
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The difference between peak and average signal
Crest factor in dB=10log(peak/average) |
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| WHAT IS THE CREST FACTOR OF A SINE WAVE? |
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WHAT IS THE DIFFERENCE BETWEEN AES PINK NOISE AND TRADITIONAL PINK
NOISE? |
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| AES pink is filtered so that it has 6dBCF and traditional pink noise has a crest factor of 10dB |
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| Peak level -> Noise floor |
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The result of atoms bumping into each other
Electronic noise |
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| WHY ARE WE FORCED TO DEAL WITH SYSTEM GAIN STRUCTURE? |
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There is no standard noise floor level
There is no standard peak input/output level |
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| HOW MANY VOLTS DOES 0 dBu EQUAL? |
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WHAT DEVICES ARE USED TO ADJUST ATTENUATION WHEN SETTING A SYSTEM’S GAIN
STRUCTURE? |
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External pads
Onboard input/output controls provided they are “before” the preamp |
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| WHAT IS THE PURPOSE OF A SYSTEM LIMITER? |
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To act as an early warning device that allows you to take measures to protect the system
“Canary in a coal mine” |
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| WHAT RATIO SETTING IS BEST FOR A SYSTEM LIMITER? |
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WHEN USING AN OSCILLOSCOPE TO FIND CLIP POINTS, HOW DO YOU CONNECT THE LEADS
OF THE SCOPE TO THE DEVICE UNDER TEST? |
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Tie low (pin 3) to ground (pin 1)
This allows you to read accurate voltage |
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| BEFORE PHYSICALLY SETTING GAIN STRUCTURE, WHY DO YOU FIRST RUN SIGNAL THROUGH THE SYSTEM? |
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| To check the integrity of the system |
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| WHY WOULD WE ZERO OUT AN EQ BEFORE ATTEMPTING TO SET GAIN STRUCTURE? |
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Any cuts or boosts will affect the EQ output during calibration
Log the existing curve before zeroing to prevent possible hurt feelings |
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| WHAT IS AMPLIFIER INPUT SENSITIVITY? |
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| The amount of voltage required at an amplifier’s input to produce full rated output |
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| WHAT ARE THE TWO COMPONENTS THAT MAKE UP A RADIO WAVE? |
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Magnetic Field (H Field)
Electric Field (E Field) – determines polorization |
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| Base unmodulated frequency the TX and RX remain locked to |
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| NAME TWO TYPES OF MODULATION? |
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WHAT TYPE OF MODULATION IS USED FOR WIRELESS MICROPHONE AND INEAR
–MONITOR SYSTEMS? WHY? |
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| Frequency modulation has a wider frequency response ( 50-16khz) and better dynamic range (90+dB) |
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| WHAT TWO TYPES OF AUDIO SIGNAL PROCESSING ARE USED IN TRANSMITTING AND RECEIVING? WHY? |
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Pre/post emphasis eq
Companding |
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| WHAT DOES TRUE DIVERSITY MEAN? |
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| The ability to sample the radio field 2 or more locations and/or the ability to select/combine the resulting signal |
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| WHAT DIVERSITY DESIGN IS MOST COMMON? |
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| Receiver switching diversity |
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| WHAT IS THE MINIMUM SIZE FOR A TRANSMITTING OR RECEIVING ANTENNA? |
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| 1/4 the size of the wavelength you are transmitting or receiving |
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WHAT IS THE BEST WAY TO MAINTAIN MAXIMUM EFFICIENCY BETWEEN A
TRANSMITTING AND RECEIVING ANTENNA? |
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| Line of sight between TX and RX |
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| NAME 4 TYPES OF COMMONLY USED ANTENNA DESIGNS. |
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Ground Plane
Whip
Yagi
Helical |
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WHAT ARE THE TWO TYPES OF ANTENNA DISTRIBUTION AND WHEN WOULD
WE USE THEM? |
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Passive (up to 2)
Active (more than 2) |
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| WHAT CAUSES “DROP OUT”, “NOISE UP” AND “HITS”? |
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Obstructions
Dead or dying batteries
Multi-path effects |
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| WHAT IS THE PURPOSE OF THE SQUELCH CIRCUIT? |
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| To mute the audio output of the receiver when RF signal level falls below a set threshold |
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| WHICH FREQUENCY BAND HAS its TRANSMITTER POWER LIMITER TO 50mW? |
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| WHICH FREQUENCY BAND HAS its TRANSMITTER POWER LIMITER TO 250mW? |
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| WHICH FREQUENCY BAND ILEGAL TO USE AS OF JUNE 2010? |
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| NAME SOME UNIQUE BENEFITS EAR MONITOR SYSTEMS PROVIDE. |
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Mobility
Safer On Ears
Stage Site Lines |
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| GIVE SOME APPLICATION EXAMPLES FOR AN IN EAR MONITOR SYSTEM. |
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Theater
Broadcast
Live Performance
Studio Monitoring |
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| A BASIC WIRELESS IN EAR MONITOR SYSTEM CONSIST OF: |
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Console
Multi-band Peak Limiter/Processor
Transmitter
Receiver
Ear Molds |
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WHY IS IT IMPORTANT TO DRIVE AN IN EAR MONITOR SYSTEM TRANSMITTER
PROPERLY? |
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If the input is too low, you will have to operate the receiver volume at too high a level leading to excessive noise
If the input is too high, you will cause overmodulation distortion. There is also a danger of bleed into adjacent radio channels |
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| WHY IS A PEAK LIMITER NECESSARY AT THE TRANSMITTER INPUT? |
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To prevent hearing damage due to a level spike or feedback loop
To enhance the mix |
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WHAT BAND POSITIONS TYPICALLY USE A HARDWIRED IN EAR MIX AS
OPPOSED TO A WIRLESS ONE |
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| WHAT IS THE FIRST THING YOU NEED TO DO TO OBTAIN CUSTOM EAR MOLDS? |
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| Go to a hearing aid center or an audiologist and have impressions taken of your ears |
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| HOW DOES AN AMBIENT MICROPHONE FED INTO A MUSICIAN’S IN EAR MONITOR MIX HELP THE MUSICIAN? |
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It helps the musicians hear crowd response
Helps with localization when using isolating
Allows communication on stage |
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| EXPLAIN WHY A MONITOR WEDGE WOULD BE USED IN COMBINATION WITH AN IN-EAR MIX. |
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| WHAT IS MULTI-BAND LIMITING? |
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| Multi Band Limiters allow separate limiter control over multiple frequency bands |
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| NAME SOME TECHNIQUES (BESIDES A WEDGE) USED TO ENHANCE THE LOW END OF AN IN EAR MIX. |
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Bass “Shaker”
Side Fill Subs |
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| WHAT ADVANTAGE DOES THE FOCAL POINT OF AN ARRAY OFFER? |
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It helps us determine accurate splay angles
Point at which a listener in the “far field” perceives the sound originating |
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| HOW DOES THE TRAPEZOID SHAPE HELP IN FORMING ARRAYS? |
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Helps achieve a higher array density
Helps mechanically align multiple speakers |
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| HOW DOES THE TRAPEZOID SHAPE HELP IN FORMING ARRAYS? |
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Helps achieve a higher array density
Helps mechanically align multiple speakers |
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| WHAT ARE THE TWO PRIMARY FACTORS THAT AFFECT ARRAY PERFORMANCE? |
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Coverage angle of an individual speaker
Splay angle between adjacent angles |
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| WHAT ARE THE TWO BASIC WAYS TO ADJUST THE COVERAGE ANGLE OF A POINT SOURCE ARRAY? |
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Electronically (amplitude tapering)
Mechanically |
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| WHAT ARE 4 BASIC TYPES OF POINT SOURCE ARRAYS? |
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Electronically (amplitude tapering)
Mechanically |
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| WHAT ARE 4 BASIC TYPES OF POINT SOURCE ARRAYS? |
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Point source wide (splayed)
Point source narrow (tight)
Point destination (split xfire)
Exploded (split point source) |
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| WHAT TYPE OF ARRAY IS RECOMMENDED FOR FRONTFILL APPLICATIONS? |
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Split parallel
Flown center cluster
Onstage fill |
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| WHAT POINT SHOULD FRONTFILL SPEAKERS OVERLAP? |
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| 6dB down point (2k) at the first row of listeners |
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| WHY ARE DELAY FILLS USED? |
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Outdoors: To overcome the natural attenuation of high frequencies by the air
Indoors: To increase the direct to reverberant sound ratio |
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| WHAT IS A FICTICIOUS SOURCE? |
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A point used for the time reference of the system
All speaker systems are delayed to this point |
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| NAME SOME IMPORTANT CONSIDERATIONS WHEN USING DELAY TOWERS. |
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Maintain the same axis as the mains
Many small zones are more effective than 1 big one
Make them transparent to the mains |
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| WHAT IS THE DIFFERENCE IN LEVEL BETWEEN HALF SPACE AND ? SPACE? |
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| WHAT IS THE DIFFERENCE BETWEEN A DIRECTIVITY FACTOR AND A DIRECTIVITY INDEX? |
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Factor is beam width expressed as “Q”
Index is the increase in sound pressure level on axis due to confinement |
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| WHAT IS SO IMPORTANT ABOUT A HORN’S CUT OFF FREQUENCY? |
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| The lowest frequency a horn can safely produce and maintain acoustic loading |
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EXPLAIN THE PROPER POWER UP AND POWER DOWN SEQUENCE FOR A
PRO AUDIO SYSTEM. |
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Turn amps on last
Turn amps off first
Digital consoles: Racks before console |
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| NAME 3 METHODS USED TO TEST A LOUDSPEAKER DRIVER. |
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Sine wave sweep station
Multimeter signal generator
Battery (CONE DRIVER ONLY) |
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| NAME THE TWO MODES USED WITH A DMM WHEN TESTING LOUDSPEAKERS |
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| NAME 3 BENEFITS OF USING FERROFLUID. |
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Heat dissipation
Coil centering in gap
Damping |
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| NAME 3 TYPES OF MATERIAL USED TO MAKE COMPRESSION DRIVER DIAPHRAGMS. |
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Aluminum
Beryllium
Titanium |
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| NAME 2 BENEFITS OF ADOPTING A THOROUGH LABLING SCHEME FOR YOU AUDIO SYSTEM. |
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Detect bad amplifiers
Show stage hands how to hook up PA |
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| NETWORKS ARE CLASSIFIED USING TWO PROPERTIES, NAME THEM. |
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| NAME THE THREE COMMON NETWORK TOPOLOGIES |
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| WHAT WOULD THE NUMBER 137 LOOK LIKE IN BINARY? |
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| WHAT IS THE BASE 10 NUMBER 137 IN HEXADECIMAL NOTATION? |
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| WHAT IS THE DIFFERENCE BETWEEN BASEBAND AND BROADBAND TRANSMISSION? |
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Base band sends binary values directly as pulses of voltage or current.
A broadband transmission is an analog communication strategy in which multiple channels are used simultaneously. |
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| WHAT IS THE DIFFERENCE BETWEEN SINGLE ENDED AND DIFFERENTIAL? |
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| Differential is to balanced as Single ended is to Unbalanced.
Single Ended – All data lines share one ground. |
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| WHAT IS ASYNCHRONOUS TRANSMISSION? |
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| A communication strategy that uses a start and stop bit to indicate the beginning and end of a transmission rather than using a constant timing sequence as in synchronous transmission. |
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| WHAT IS SYNCHRONOUS TRANSMISSION? |
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| A communications strategy that uses timing to control transmission. |
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| WHAT IS ISOCHRONOUS TRANSMISSION? |
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| An isochronous transmission is one whose operation is dependent on constant time intervals. |
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| WHAT IS COBRANET TECHNOLOGY? |
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| Cobranet is a combination of hardware, network protocol, and firmware…that allows us to send digital audio in real time over Ethernet. (64 channels, 48K) |
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| WHAT IS THE JOB OF A “CONDUCTOR” IN A NETWORK USING COBRANET ? |
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| WHAT DOES “10/100BASE T” TELL YOU ABOUT A NETWORK? |
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Speed
Signal Type
Cable Type |
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| WHAT IS DATA TERMINAL EQUIPMENT? |
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| Refers to any devices that produces or consumes data on a network |
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| GIVE TWO EXAMPLES OF DATA COMMUNICATION EQUIPMENT. |
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| A protocol specifies a common set of rules and signals the devices on the network use to communicate. |
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| WHAT 3 THINGS DOES OSI ALLOW US TO DO CONCERNING PROTOCOLS? |
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Provides a common way to analyze protocols
Allows one to compare protocols
Helps one troubleshoot network problems |
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| Used to identify a node on a network |
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| WHAT LAYER OF OSI DOES AN IP ADDRESS OPERATE? |
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| WHAT ARE THE TWO WAYS AN IP ADDRESS CAN BE ASSIGNED TO A NODE ON A NETWORK? |
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| WHICH OSI LAYER HANDLES PORT ACCESS? |
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| Layer 4 (application specific) |
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