Set your listening position in the vehicle as specified by IASCA rules (typically, the driver’s seat or center position as judged).
Play each Bark (Spectral Balance) track in order, from lowest to highest frequency.
Each Bark track consists of pink noise filtered into a narrow frequency band (“Bark band”) and plays in a repeating loop.
For each track, listen for the apparent center and evenness of the sound between left and right speakers.
If a particular Bark band appears noticeably louder, softer, shifted left/right, or is missing, this indicates a frequency imbalance.
The ideal is for each Bark band to sound centered, with equal loudness and no major dips or peaks.
Use these observations to identify required adjustments to your equalizer, crossover, or speaker setup, aiming for a flat, neutral response across all bands.
Repeat the test after making adjustments until all Bark tracks sound even, centered, and consistent in level.
IASCA Notes
These tracks are used in official IASCA sound quality competitions for the “Spectral Balance” category.
Ensure all other vehicle noise sources are turned off during testing.
For further rules, see the IASCA Sound Quality Handbook or iasca.com.
