Yamaha Q2031A - Manual (Page 7)

ACOUSTIC CONTROL
I
The Q2031 A’s 20 Hz to 20 kHz spectrum enable it to be applied in a variety of ways to improve the listening environment. Some
of these are described below.
• Maintaining Ideal Indoor Propagation Characteristcs
Speaker systems that demonstrate flat responses in anechoic
rooms will normally have irregular responses in a concert hall
due to acoustic conditions. The Q2031A equalizer can be
used to minimize these irregularities.
To smooth the playback system response, connect a pink
noise generator to the consoie so that pink noise is radiated
from the speakers. While measuring the pink noise at
strategic iistening positions in the room using a spectrum
analyzer, adjust the Q2031A until preferred response is dis-
piayed.
SPEAKER
-OM
SPEAKER
SPECTRUM
ANALYZER
• Ensuring Adequate Feedback Margins in Stage Monitor
Feedback can resuit in howling or ringing being generated at
specific frequencies dependent on the monitor system and
microphone characteristics. The Q2031A can be adjusted to
reduce leveis at the effected frequencies and thereby control
the feedback, but a pink noise generator and a spectrum
analyzer are again required.
Set the equipment up just as for an actual performance.
Connect the pink noise generator to the spare input connec-
Systems
tors on the console. After ensuring that pink noise is being
properly radiated from aii monitor speakers, graduaily raise
the output level until it is evident at which frequencies feed­
back wiil occur, using the spectrum analyzers and calbrated
microphone near the monitor speakers. Use the Q2031A to
reduce the ievels of these specific frequencies and provide a
safety margin against feedback when the output level is
raised.
Measuring instruments can only go so far in providing sound
realism. After you have completed the indoor propagation
and feedback compensating adjustments, make the final
adjustments using the ultimate judge, your trained ears.
A Pink Noise Generator generates a uniform level of
random noise throughout the audio spectrum. (Equal
Energy per octave)
A Spectrum Analyzer divides the audio spectrum into
ranges and indicates the sound pressure for each range.