Subjective listener aspect

Acoustic quality

Single number frequency averaging (Hz)

Just Noticeable Difference (JND)

Typical range*

Subjective level of sound

Sound Strength, G, in dB

500 to 1000

1 dB

-2 dB; +10 dB

Perceived reverberance

Early Decay Time, EDT, in s

500 to 1000

Rel. 5%

1.0s; 3.0s

Perceived clarity of sound

Clarity, C₈₀, in dB
Definition, D₅₀
Centre Time, T_s, in ms

500 to 1000
500 to 1000
500 to 1000

1dB
0.05
10ms

-5 dB; +5 dB
0.3; 0.7
60 ms; 260 ms

Apparent Source Width, ASW

Early Lateral Energy Fraction LF or LFC

125 to 1000

0.05

0.05; 0.35

Listeners Envelopement

Late Lateral Sound Level, LG in dB

125 to 1000

Not known

-14 dB; +1 dB

Ensemble conditions**

Early Support, ST_Early (dB)

250 to 2000

Not known

-24 dB; -8dB

Perceived reverberance**

Late Support, ST_Late (dB)

250 to 2000

Not known

-24dB; -10dB

* Typical range is for averaged values in single positions in auditorium of non-occupied concert– and multi-purpose halls up to 25000 m³ .
** Performers listener aspect, on orchestra platform. See also Stage Acoustics.