EQ tips for eliminating background noise from your mixes (a table of note frequencies)

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Eliminating background noise from mixes[This article was written by Alex Andrews of Ten Kettles Inc. Their new music theory app, “Waay: Music theory that matters” is now available. Click here to learn about its video lessons, interactive exercises, progress-tracking tools, and more.]

What’s the frequency of C, and why should you care?

It’s 261.6 Hz. Why would we ever need to know this? Well, there could be a few different reasons, but one has to do with mixing audio. When equalizing (EQing) an audio track, one common challenge is filtering out background noise—especially if the track was recorded with a microphone. Here’s what the mic might be picking up:

* The rumble of a streetcar or truck going by in the distance

* An accidental knock of the microphone stand

* A door closing somewhere in your building

Your best route to eliminating background noise is to cut it out at the source, but in many cases (barring time travel) that’s just not possible. So we use an equalizer, or EQ, to lend a helping hand.

Take a guitar track for example. What’s the lowest sound you’d expect to come from a guitar? If it’s in standard tuning, the lowest string is tuned to E2, which has a frequency of 82.4 Hz (see the table below). This means that any sound below ~80 Hz is not guitar. So, if we filter out everything below that frequency, we cut out the low noise (like the streetcar rumble) but keep all that great guitar sound. Not bad! The name for this kind of filter is a high-pass filter, because it lets all the high frequencies pass—and keeps out the low ones.

Below is a table of all the note frequencies, with the highest and lowest notes of various instruments highlighted. The first column is the octave number. For example, the low E string on a guitar is tuned to E2—that’s E in the 2nd octave.

Note Freq. (Hz) Instrument
0 C 16.35
C♯/D♭ 17.32
D 18.35
D♯/E♭ 19.45
E 20.60 Approximate lower limit of human hearing
(increases with age)
F 21.83
F♯/G♭ 23.12
G 24.50
G♯/A♭ 25.96
A 27.50
A♯/B♭ 29.14
B 30.87 Lowest note of a 5-string bass
1 C 32.70
C♯/D♭ 34.65
D 36.71
D♯/E♭ 38.89
E 41.20 Lowest note of a 4-string bass
F 43.65
F♯/G♭ 46.25
G 49.00
G♯/A♭ 51.91
A 55.00
A♯/B♭ 58.27
B 61.74
2 C 65.41
C♯/D♭ 69.30
D 73.42
D♯/E♭ 77.78
E 82.41 Lowest note of a guitar
F 87.31
F♯/G♭ 92.50
G 98.00 Approximate low-end of male vocals
(depends greatly on individual)
G♯/A♭ 103.8
A 110.0
A♯/B♭ 116.5
B 123.5
3 C 130.8
C♯/D♭ 138.6
D 146.8
D♯/E♭ 155.6
E 164.8
F 174.6
F♯/G♭ 185.0
G 196.0 Approximate low-end of female vocals
(depends greatly on individual)
G♯/A♭ 207.7
A 220.0
A♯/B♭ 233.1
B 246.9
4 C 261.6 (Middle C)
C♯/D♭ 277.2
D 293.7
D♯/E♭ 311.1 Highest note of a 4 or 5-string bass
E 329.6
F 349.2
F♯/G♭ 370.0
G 392.0 Approximate high-end of male vocals
(depends greatly on individual)
G♯/A♭ 415.3
A 440.0
A♯/B♭ 466.2
B 493.9
5 C 523.3
C♯/D♭ 554.4
D 587.3
D♯/E♭ 622.3
E 659.3
F 698.5
F♯/G♭ 740.0
G 784.0 Approximate high-end of female vocals
(depends greatly on individual)
G♯/A♭ 830.6
A 880.0
A♯/B♭ 932.3
B 987.8
6 C 1047 Highest note of a 20-fret guitar
C♯/D♭ 1109
D 1175
D♯/E♭ 1245
E 1319
F 1397
F♯/G♭ 1480
G 1568
G♯/A♭ 1661
A 1760
A♯/B♭ 1865
B 1976
7 C 2093
C♯/D♭ 2217
D 2349
D♯/E♭ 2489
E 2637
F 2794
F♯/G♭ 2960
G 3136
G♯/A♭ 3322
A 3520
A♯/B♭ 3729
B 3951
8 C 4186
C♯/D♭ 4435
D 4699
D♯/E♭ 4978
E 5274
F 5588
F♯/G♭ 5920
G 6272
G♯/A♭ 6645
A 7040
A♯/B♭ 7459
B 7902
9 C 8372
C♯/D♭ 8870
D 9397
D♯/E♭ 9956
E 10,548
F 11,175
F♯/G♭ 11,840
G 12,544
G♯/A♭ 13,290
A 14,080
A♯/B♭ 14,917
B 15,804
10 C 16,744
C♯/D♭ 17,740
D 18,795
D♯/E♭ 19,912 Approximate upper limit of human hearing
(decreases with age)
E 21,096
F 22,351
F♯/G♭ 23,680
G 25,088
G♯/A♭ 26,580
A 28,160
A♯/B♭ 29,834
B 31,609

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Bio: Alex Andrews is an engineer, musician, and runs Ten Kettles Inc in Toronto, Canada. Ten Kettles is an indie app company that builds apps for music education. Their newest app, “Waay: Music theory that matters,” brings together video lessons, interactive exercises, and progress-tracking tools to teach music theory for songwriters. You can find out more here.

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  • David Ma

    Cool that table will be very very helpful for me in the future! Thanks big bunch!

    • Alex (Ten Kettles)

      No problem, glad you find it useful!

  • That’s a great chart for helping to determine where to set a high-pass filter. But it would be a little more clear if you explained that instruments do not only produce fundamental frequencies.

  • Alex (Ten Kettles)

    Hey Jon, thanks for the comment! You’re right that an instrument’s sound includes a range of frequencies, with the “fundamental frequency” being the lowest. For setting high-pass filters, this is the frequency we care about because it’s the lowest pitch in the sound—and we want to be careful not to cut it off unintentionally!