Microphone Calibration

Why Calibrate?

No microphone is perfectly flat. Even measurement microphones have small deviations from a flat response, typically ±2-3 dB at the frequency extremes.

A calibration file tells Sounn exactly how your specific microphone deviates from flat, allowing Sounn to compensate. Without calibration:

Your measurement includes the mic's frequency response errors
Correction filters will "correct" for problems that don't actually exist in your room
Results are less accurate, especially at high frequencies

How Much Does It Matter?

For most users, uncalibrated measurements with a decent measurement mic (UMIK-1, etc.) are still quite useful. But if you want the most accurate results possible, calibration eliminates one source of error.

Getting Calibration Files

Individual Calibration (Best)

Many measurement microphones come with individual calibration files measured for your specific unit:

miniDSP UMIK-1/UMIK-2: Individual calibration file downloadable from miniDSP website using serial number
Earthworks M23/M30: Individual calibration certificate and file included
Dayton Audio EMM-6: Individual calibration available for purchase from Cross-Spectrum Labs

Generic Calibration

If individual calibration isn't available, generic calibration files represent the "average" response of a microphone model. This is better than no calibration but won't account for your specific unit's variations.

90° vs 0° Calibration

Many mics have different calibrations for different orientations:

90° (perpendicular): Use when mic points straight up—recommended for room measurement
0° (on-axis): Use when mic points directly at the sound source

UMIK Calibration

For miniDSP UMIK microphones, download the 90° calibration file from the miniDSP website. The file will be named something like "UMIK-1_90deg_123456.txt" where 123456 is your serial number.

Importing Calibration Files

Supported Formats

Sounn accepts calibration files in these formats:

.txt - Space or tab-separated frequency/dB pairs
.cal - REW-compatible calibration format
.csv - Comma-separated values

Import Steps

Open Sounn and go to Settings (gear icon)
Navigate to Devices
Find your microphone in the Input Device section
Click Import Calibration...
Select your calibration file
Verify the calibration curve appears in the preview
Click Apply

Settings panel showing calibration file import

Import your calibration file in Settings > Devices

Calibration File Format

A typical calibration file looks like this:

20.0    -0.15
25.0    -0.10
31.5    -0.05
40.0     0.00
50.0     0.05
...
16000   -1.20
20000   -2.50

Each line contains a frequency (Hz) and the microphone's deviation from flat at that frequency (dB). Positive values mean the mic is "hot" at that frequency; negative values mean it's "cold."

Verifying Calibration

Visual Check

After importing, Sounn displays the calibration curve in the Settings panel. Verify it looks reasonable:

Most of the curve should be within ±2-3 dB
High-frequency roll-off is common and expected
Very low frequencies may show more variation
Sudden jumps or spikes might indicate a corrupted file

Practical Test

Take a measurement with and without calibration enabled:

Take a measurement with calibration enabled
Disable calibration in Settings
Take another measurement from the same position
Compare the two measurements

You should see small differences, especially at high frequencies. If the differences are dramatic (more than 5-6 dB), verify you have the correct calibration file for your mic.

Wrong Calibration

Using a calibration file from a different microphone will make your measurements less accurate, not more. Always verify the serial number matches your mic.