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Learn About Audio Testing

Everything you need to know about frequency testing, speaker calibration, and hearing assessment

When you are ready to turn calibration observations into training prompts, tap into PromptCraft for instant workbook-style practice scenarios tailored to your sessions, and explore FictionForge when you want to turn technical notes into engaging long-form explainers.

Audio Testing Guide

Audio testing is the process of evaluating audio equipment, systems, or hearing capabilities using precision test signals. Whether you're a professional audio engineer, audiophile, or just curious about your hearing, understanding basic audio testing principles will help you get the most accurate results.

Why Test Audio Equipment?

  • Speaker Calibration: Ensure flat frequency response and proper placement
  • Equipment Verification: Test amplifiers, DACs, and audio interfaces for distortion
  • Room Acoustics: Identify resonances, dead spots, and frequency buildup
  • Quality Control: Verify that gear performs to manufacturer specifications
  • Troubleshooting: Diagnose issues like phase problems or frequency dropouts

Basic Testing Workflow

  1. Set Safe Volume: Always start at low volume to prevent equipment damage or hearing loss
  2. Choose Test Signal: Select appropriate tone (sine wave, sweep, pink noise, etc.)
  3. Run Test: Play test signal through your equipment
  4. Measure/Listen: Use measurement tools or critical listening to evaluate
  5. Document Results: Record findings for comparison over time
  6. Make Adjustments: Apply corrections based on test results

Frequency Reference Charts

Frequency Ranges

Sub-Bass (20-60 Hz)
Felt more than heard. Subwoofers, kick drums, organ pedals
Bass (60-250 Hz)
Bass guitars, low male voices, toms, fundamental notes
Low Midrange (250-500 Hz)
Body of guitars, lower harmonics, warmth
Midrange (500-2000 Hz)
Vocals, guitars, pianos, most musical content
Upper Midrange (2-4 kHz)
Presence, clarity, definition, attack
Treble (4-8 kHz)
Cymbals, hi-hats, sibilance, brilliance
High Treble (8-20 kHz)
Air, sparkle, shimmer - often lost with age

Musical Note Frequencies

A440440.00 Hz (Concert Pitch)
C4261.63 Hz (Middle C)
C5523.25 Hz
A3220.00 Hz
E282.41 Hz (Low E string)

Common Test Frequencies

1 kHzStandard reference tone
10 kHzHigh-frequency test
100 HzBass reference

Hearing Range by Age

Average upper frequency hearing limits by age (approximate):

20 kHz
Under 20
18 kHz
20-30 years
15 kHz
40-50 years
12 kHz
60+ years

Equipment Testing Procedures

How to Test Speakers Properly

  1. Position Speakers: Place at equal distances from listening position, aimed at ear level. Measure distances to ensure symmetry.
  2. Run Frequency Sweep: Use 20 Hz - 20 kHz sweep to identify resonances, dropouts, or distortion. Listen for rattles or buzzing.
  3. Test Phase Alignment: Play identical tones on both speakers. Sound should be centered. If image shifts, check phase/polarity.
  4. Check Frequency Response: Use pink noise and spectrum analyzer (or ears) to identify peaks and dips. Target flat response.
  5. Test Subwoofer Integration: Play bass sweeps to find port tuning frequency and ensure smooth crossover with mains.

Headphone Testing

  • Driver Matching: Play single tones alternating L/R to verify both drivers sound identical in volume and timbre.
  • Frequency Extension: Test with sweeps to determine actual bass extension and treble roll-off compared to specifications.
  • Distortion Check: Play loud tones at 100 Hz, 1 kHz, 10 kHz. Listen for distortion, crackling, or rattling.

Room Acoustics 101

Your room significantly affects what you hear. Understanding room acoustics helps you achieve better sound:

  • Standing Waves: Occur at frequencies where wavelength divides evenly into room dimensions. Causes bass buildup or cancellation.
  • First Reflections: Sound bouncing off walls/ceiling/floor once before reaching ears. Can cause comb filtering and imaging issues.
  • Reverberation Time: How long sound takes to decay. Too much = muddy, too little = dead.
  • Sweet Spot: Optimal listening position where frequency response is most balanced and stereo image is centered.

Audio Testing Glossary

Frequency (Hz)
Number of cycles per second. Human hearing: 20 Hz - 20 kHz.
Decibel (dB)
Logarithmic unit for measuring sound pressure level or gain.
THD (Total Harmonic Distortion)
Measure of unwanted harmonics added to signal. Lower is better.
Frequency Response
How equipment or room responds across frequency spectrum.
Phase
Timing relationship between waveforms. Critical for stereo imaging.
Pink Noise
Equal energy per octave. Sounds like "shhhh", used for calibration.
White Noise
Equal energy per Hz. Brighter than pink, used for some tests.
Sine Wave
Pure tone at single frequency. Fundamental test signal.
Sweep
Tone that changes frequency over time. Reveals full-range response.
SPL (Sound Pressure Level)
Measure of sound loudness in dB. 85 dB+ can damage hearing.

Interactive Demos

Hear the Difference: A/B Comparisons

Compare different audio characteristics side by side. Click "Play A" or "Play B" to hear the difference.

Sine Wave vs Square Wave (440 Hz)

A sine wave is pure and smooth. A square wave has harsh harmonics.

High Frequency vs Low Frequency

Compare bass (100 Hz) with high treble (10,000 Hz).

Frequency Tour: Hear What You're Testing

Click each frequency range to hear what it sounds like. This helps you understand what you're listening for during tests.

Waveform Comparison

Different waveforms produce different timbres. All at 440 Hz (Concert A) for easy comparison.

Sine Wave

Pure, smooth tone with no harmonics. The fundamental building block of all sounds.

Square Wave

Rich in odd harmonics (3rd, 5th, 7th). Hollow, clarinet-like sound.

Sawtooth Wave

Contains all harmonics. Bright, buzzy sound like classic synthesizers.

Triangle Wave

Soft, mellow tone with weak odd harmonics. Similar to sine but with more character.

Hearing Health and Protection

Protect Your Hearing

Hearing damage is permanent and cumulative. Always use caution when testing audio equipment at high volumes.

Safe Listening Levels

  • 85 dB: Maximum safe exposure = 8 hours
  • 88 dB: Maximum safe exposure = 4 hours
  • 91 dB: Maximum safe exposure = 2 hours
  • 100 dB: Maximum safe exposure = 15 minutes
  • 110 dB+: Risk of immediate damage

Protection Tips

  • Always start testing at low volume and increase gradually
  • Take regular breaks during extended listening sessions
  • Use hearing protection when working with loud equipment
  • Monitor for early warning signs: ringing, muffled hearing, ear fatigue
  • Get regular hearing tests from a professional audiologist
  • Be especially careful with headphones - easier to reach damaging levels

Looking for more audio tools?

Check out AudioKit →