Table 1: Effects of Equalisation on Voice Reproduction
1/3 Octave centre frequency (Hz) | Effect on voice |
40, 50, 63, 80,100,125, | Sense of power in some outstanding |
| bass singers. |
160, 200, 250, | Voice fundamentals. |
315, 400, 500 | Important for voice quality. |
630, 800, 1k | Important for voice naturalness. Too |
| much boost in the 315 to 1k range |
| produces a telephone like quality. |
1.25 to 4k | Vocal fricatives - accentuation of vocals. |
| Important to speech intelligibility. Too |
| much boost between 2 and 4kHz can |
| mask certain speech sounds e.g “m”, “b” |
| and “v” can become indistinguishable. |
| Too much boost anywhere between 1 and |
| 4kHz can produce “listening fatigue”. |
| Vocals can be highlighted by slightly |
| boosting the vocal at 3kHz and at the |
| same time slightly dipping the instruments |
| at the same frequency. |
| Accentuation of voice. |
5, 6.3, 8k | The range from 1.25 to 8k governs the |
| clarity of voice. |
10,12.5, 16k | Too much boost causes sibilance. |
Table 2: Effects of Equalisation on Music Reproduction
1/3 Octave centre frequency (Hz) | Effect on music |
31,40, 50, 63 | Fundamentals of bass drum, tuba, double |
| bass and organ. These frequencies give |
| music a sense of power. If over- |
| emphasised they make the music “muddy”. |
| 50 or 60Hz band also used to reject ac. |
| Mains hum. |
80, 100, 125 | Fundamentals of lower tympani. Too much |
| boost produces excessive “boom”. 100 or |
| 125Hz also used for hum rejection. |
160, 200, 250 | Drum and lower bass. Too much boost |
| produces excessive “boom”. Also useful |
| for 3rd harmonic mains hum rejection. |
315, 400, 500 | Fundamentals of string and percussion. |
630, 800, 1k | Fundamentals and harmonics of strings, |
| keyboards and percussion. |
| Boosting the 600 - 1kHz range can make |
| instruments sound horn like. |
1.25 to 4k | Drums, guitar accentuation of vocals, |
| strings and brass. |
| Too much bass in the 1 to 2kHz range can |
| make instruments sound tinny. Too much |
| boost anywhere between 1 to 4kHz can |
| produce “listening fatigue”. |
5,6.3, 8k | Accentuation of percussion, cymbals and |
| snare drum. |
| Reduction at 5kHz makes overall sound |
| more distant and transparent. |
| Reduction of tape hiss and system noise. |
| The 1,25 to 8k governs clarity and |
| definition. |
10, 12.5, 16k |
|
| Cymbals and overall brightness. Too much |
| boost causes sibilance. |
| Reduction of tape hiss and system noise. |
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