Total Harmonic Distortion Calculator
Convert between THD percentage and distortion attenuation in decibels for audio systems
THD Calculator
Enter percentage value (0.001% to 100%)
Conversion Results
Formulas used:
THD% to dB: aₖ = 20 × log₁₀(k/100)
dB to THD%: k = 10^(aₖ/20) × 100
THD Quality Guidelines
Example Calculations
High-Quality Audio Equipment
THD: 0.01% (very low distortion)
Distortion Attenuation: 20 × log₁₀(0.01/100) = -80 dB
Quality: Excellent - virtually inaudible distortion
Consumer Audio Equipment
THD: 0.1% (acceptable distortion)
Distortion Attenuation: 20 × log₁₀(0.1/100) = -60 dB
Quality: Very Good - minimal audible distortion
Basic Audio System
THD: 1.0% (noticeable distortion)
Distortion Attenuation: 20 × log₁₀(1.0/100) = -40 dB
Quality: Fair - distortion may be audible
THD Applications
Audio Amplifiers
Measure amplifier linearity and fidelity
Speakers
Evaluate speaker driver performance
Headphones
Test headphone audio quality
Microphones
Assess microphone signal clarity
Conversion Formulas
THD Measurement Tips
Lower THD values indicate better audio quality
THD below 0.1% is generally inaudible to humans
Distortion attenuation is always negative in dB
Every audio component adds some level of distortion
Understanding Total Harmonic Distortion
What is THD?
Total Harmonic Distortion (THD) is a parameter that measures the harmonic distortion present in a signal. It's defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency.
Why is THD Important?
- •Measures audio system accuracy and fidelity
- •Indicates presence of unwanted harmonic frequencies
- •Helps compare audio equipment quality
- •Critical for professional audio applications
THD Measurement
THD can be expressed in two ways: as a percentage (distortion factor) or in decibels (distortion attenuation). The percentage represents how much of the output signal contains unwanted distortion.
Practical Examples
0.01% THD: High-end audio equipment
0.1% THD: Quality consumer audio
1.0% THD: Basic audio systems
3.0% THD: Poor quality audio
Human Perception
The human ear has difficulty perceiving THD levels below 0.5%, especially when it's only a small fraction of a percent. However, in critical listening environments, even small differences in THD can be significant.
Applications in Audio Systems
Professional Audio
Recording studios and live sound systems require extremely low THD (typically <0.01%) for accurate sound reproduction.
Consumer Electronics
Home audio systems typically aim for THD levels below 0.1% for good quality sound reproduction.
Testing & Quality Control
THD measurements are crucial for quality control in manufacturing audio equipment and ensuring specifications are met.