Clarity
- In concert hall acoustics, the ratio, expressed in decibels, of the energy in the first 80 milliseconds of an impulse sound arriving at a listener′s position divided by the energy in the sound after 80 milliseconds. The divisor is approximately the total energy of the reverberant sound.
- More generally, clarity refers to the degree to which the separate strands in a musical performance perceptually stand apart from one another.
- If the clarity is too low, the fast parts of the music are not readable.
- If there is no reverberation in a room, the music will be very clear and C80 will have a large positive value.
- If the reverberation is large, the music will be unclear and C80 will have a relatively high negative value.
- If the early and the reverberant sound are equal C80 goes to 0 dB.
- For orchestral music, a C80 of 0 dB to -4 dB is optimal.
- For orchestral rehearsals, a higher clarity of 1d B to 5 dB gives more control over the performances.
- For vocal performances, the clarity should in the range -4 dB and +4 dB.
- For speech, in comparison to music, Clarity is measured as the ratio of the first 50 milliseconds (C50) instead of C80.
- If the clarity is too low, the fast parts of the music are not readable.
- A long reverberation time adds richness and fullness, but at the same time decreases clarity of articulation. So fullness and richness work against clarity, and a reasonable reverberation time must be reached by an appropriate compromise of clarity versus fullness.
- At specific locations in auditoriums, the direct sound may be blocked and so the proportion of reverberant sound versus direct sound reaching the location decreases the clarity.
See also: Apparent Source Width, Haas Effect, Reverberation Time, Sound Definition.
Subjects: Audio