Overview

WaveMetrics calculates the speed of sound in air based on environmental conditions (altitude, temperature, and humidity). It also provides related calculations including flight time, distance, and wavelength.

Perfect for live audio engineers who need accurate speed of sound calculations for delay calculations, system alignment, and acoustic measurements.

Getting Started

Enter Required Values

1. Altitude: Your elevation above sea level (feet or meters)
2. Temperature: Current air temperature (°F or °C)
3. Humidity: Relative humidity percentage (0-100%)

View Results

Once all three required values are entered, the app automatically calculates and displays:

• Speed of sound (m/s and ft/s)
• Time per distance (ms/ft and ms/m)

Optional Features

Calculate Wavelength

Enter a frequency (Hz or kHz) to calculate the wavelength of sound at the current environmental conditions.

How to Use:

1. Enter the required environmental values (altitude, temperature, humidity)
2. Enter a frequency in the wavelength field
3. View the calculated wavelength based on the current speed of sound

Use Case: Determine the physical length of sound waves for acoustic measurements, speaker placement, or room analysis.

Calculate Flight Time or Distance

Use the Distance/Time input field with two modes:

Distance Mode

• Enter a distance (feet or meters)
• App shows the flight time in milliseconds for that distance

Use Case: Calculate how long it takes for sound to travel a specific distance, useful for delay calculations.

Time Mode

• Switch to "Time" mode
• Enter time in milliseconds
• App shows the distance traveled in both feet and meters

Use Case: Determine how far sound travels in a given time period, useful for system alignment and delay settings.

Understanding Results

• Speed of Sound: How fast sound travels in the current conditions (displayed in both meters per second and feet per second)
• Time per Distance: Milliseconds it takes for sound to travel one foot or one meter
• Flight Time: Time for sound to travel a specific distance (when distance is entered)
• Distance: Distance traveled in a given time (when time is entered)
• Wavelength: Length of one complete sound wave cycle (when frequency is entered)

Technical Details

Speed of Sound Formula

Base formula: c = 331.3 + 0.606 × T_C (m/s)

Where T_C is temperature in Celsius. The app applies corrections for:

• Humidity: Water vapor increases speed slightly
• Altitude: Lower pressure at altitude slightly reduces speed

Important: Temperature is the dominant factor; humidity and altitude have smaller effects (< 1 m/s typically).

Other Calculations

• Time per distance: ms/unit = 1000 / speed_per_second
• Flight time: time_ms = distance × ms_per_unit
• Distance from time: distance = time_ms / ms_per_unit
• Wavelength: λ = speed / frequency

Common Use Cases

Use Case 1: Delay Calculations

Scenario: You need to calculate delay times for speakers at different distances.

Solution:

1. Enter current environmental conditions (altitude, temperature, humidity)
2. Use Distance Mode to enter the distance to each speaker
3. View the flight time in milliseconds
4. Use this value to set delay times in your audio console or processor

Use Case 2: System Alignment

Scenario: Aligning multiple speaker arrays that are different distances from the source.

Solution:

1. Enter environmental conditions at the venue
2. Calculate flight times for each speaker distance
3. Use the time differences to align the system

Use Case 3: Acoustic Measurements

Scenario: Measuring room acoustics and need to know wavelength at specific frequencies.

Solution:

1. Enter environmental conditions
2. Enter the frequency you're testing
3. View the calculated wavelength
4. Use this information for room analysis and treatment decisions

Troubleshooting

No results showing?

• Ensure all three required fields (altitude, temperature, humidity) are filled
• Check that values are valid numbers
• Results appear automatically once all required fields are entered

Invalid number error?

• Use decimal numbers (e.g., 72.5, not 72 1/2)
• Distance must be between 0 and 1000
• Humidity must be between 0 and 100%
• Temperature values should be reasonable for your location

Reset the form

• Tap the "Reset" button in the top-right corner to clear all inputs
• This returns all fields to their default state

Tips

• Temperature has the largest impact on speed of sound - changes in temperature affect speed more than humidity or altitude
• Higher temperatures = faster speed of sound - sound travels faster in warmer air
• Humidity and altitude effects are small but included for accuracy - typically less than 1 m/s difference
• Use the Info section in the app for detailed formulas and explanations
• Update conditions when moving between venues or when temperature changes significantly
• For outdoor shows, check conditions at show time as temperature can change throughout the day
• For indoor venues, conditions are usually more stable, but still check temperature and humidity

Understanding Environmental Effects

Temperature

Temperature is the most significant factor affecting speed of sound:

• At 0°C (32°F): Speed ≈ 331.3 m/s (1,086 ft/s)
• At 20°C (68°F): Speed ≈ 343.4 m/s (1,127 ft/s)
• At 40°C (104°F): Speed ≈ 355.5 m/s (1,166 ft/s)

Each degree Celsius change affects speed by approximately 0.6 m/s.

Humidity

Humidity has a small positive effect on speed of sound:

• Higher humidity slightly increases speed
• Effect is typically less than 0.5 m/s
• More noticeable at higher temperatures

Altitude

Altitude has a small negative effect on speed of sound:

• Higher altitude (lower pressure) slightly decreases speed
• Effect is typically less than 1 m/s
• More noticeable at very high altitudes

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