Equalizer Frequency Calculator

An audio equalizer shapes sound by boosting or cutting specific frequency ranges — the Equalizer Frequency Calculator works out the exact filter boundaries for any EQ band so you can tune precisely without guessing. Enter your center frequency, Q factor, and gain, then select a filter type (Peaking, Low Pass, High Pass, Band Pass, or Notch) and sample rate. You'll get the filter's bandwidth in Hz and octaves, plus the lower and upper -3dB cutoff frequencies and angular frequency.

Hz

The center frequency of the EQ filter

Quality factor - higher values = narrower bandwidth

dB

Boost or cut in decibels

Results

Bandwidth

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Bandwidth (Octaves)

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Lower -3dB Frequency

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Upper -3dB Frequency

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Angular Frequency

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Frequently Asked Questions

What is Q factor in equalizer design?

Q factor (quality factor) determines the bandwidth of an EQ filter. Higher Q values create narrower, more precise frequency adjustments, while lower Q values affect a broader range of frequencies. Q is calculated as center frequency divided by bandwidth.

How do you calculate the bandwidth of an EQ filter?

Bandwidth is calculated using the formula BW = f0 / Q, where f0 is the center frequency and Q is the quality factor. The bandwidth represents the frequency range between the -3dB points of the filter response.

What's the difference between peaking and bandpass filters?

Peaking filters boost or cut frequencies around a center point while allowing all frequencies to pass through. Bandpass filters only allow frequencies within a specific range to pass, blocking frequencies outside that range.

How does sample rate affect EQ filter calculations?

Sample rate determines the maximum frequency that can be processed (Nyquist frequency = sample rate / 2). Higher sample rates allow for more precise filter calculations at high frequencies and reduce digital artifacts.

What is the relationship between Q factor and bandwidth in octaves?

Bandwidth in octaves (N) is approximately equal to 1.44/Q for narrow-band filters. This relationship helps audio engineers translate between different measurement systems when designing EQ curves.

How do I choose the right Q factor for my EQ?

For musical applications, Q values between 0.5-2.0 sound natural. Higher Q values (3-10+) are useful for surgical cuts or correcting specific resonances. Lower Q values (0.3-0.7) work well for gentle tonal shaping.

What are the -3dB cutoff frequencies?

The -3dB cutoff frequencies are the points where the filter response drops to half power (70.7% of the peak level). These frequencies define the effective bandwidth of the filter and are used to calculate Q factor.