TC1280 STEREO DIGITAL AUDIO DELAY OWNERS MANUAL Rev. 2.1, Software version 2.04
Page 8 of 9
DISTANCE MODE CALCULATION
The show distance value corresponding to the delay time setting is based on 344 meters/Sec or
1129 feet/Sec which is the speed of sound in air at 20°C and 60% humidity.
The equation for the delay time is:
where "
c
" is the speed of sound in air
A convenient formula for the speed of sound in air is:
T
in Centigrade and
c
in meters/sec
or
T
in Fahrenheit and
c
in feet/sec
The speed of sound in air at a temperature of 0 degrees C and 50% relative humidity is 331.6
m/s. The speed is proportional to the square root of absolute temperature and it is therefore
about 12 m/s greater at 20 degrees C. The speed is nearly independent of frequency and
atmospheric pressure but the resultant sound velocity may be substantially altered by wind
velocity.
Temp
12°C 14°C 16°C 18°C 20°C 22°C 24°C 26°C 28°C 30°C
Humidity 53,6°F
57,2°C 60,8°C 64,4°F 68°F 71,6°F 75,2°F 78,8°F 82,4°F 86°F
40%
339,0 340,2 341,4 342,6 343,9 345,1 346,3 347,6 348,8 350,1
60%
339,1 340,4 341,6 342,9 344,1 345,4 346,7 348,0 349,2 350,6
80%
339,3 340,5 341,8 343,1 344,4 345,7 347,0 348,3 349,7 351,0
Temp
12°C 14°C 16°C 18°C 20°C 22°C 24°C 26°C 28°C 30°C
Humidity 53,6°F
57,2°C 60,8°C 64,4°F 68°F 71,6°F 75,2°F 78,8°F 82,4°F 86°F
40%
1112 1116 1120 1124 1128 1132 1136 1140 1144 1149
60%
1113 1117 1121 1125 1129 1133 1137 1142 1146 1150
80%
1113 1117 1121 1126 1130 1134 1138 1143 1147 1152
Comment on HAAS EFFECT
- or the “principal of first arrival”. Most of us are born with the gift of being able to hear quite
easily from where in a circular sphere around us a given sound originates. As most of us are
born with two ears spaced apart, separated by a head, the direct sound from any source will
arrive at slightly different times to each ear. Even in a strong reverberant ambience our brain is
capable of ignoring the reflections and tells us the direction to the source. The Haas effect
implies also to stereophonic reproduction from only two loudspeakers.
In essence we do not "hear" the delayed sound if the subsequent arrivals are within 30
milliseconds. If the later arrivals are longer than this, two separate sounds are perceived.
The Haas effect is true even when the second arrival is louder than the first (even by as much
as 10 dB).
T
459
49
c
+
=
T
273
20
c
+
=
c
distance
time
=
