ODEON produces results in full octave bands only, according to the ISO 3382 standard. Since version 19, ODEON can accept absorption coefficients and carry out calculations in 1/3 octave bands. However, the final results will still be in full octave bands.

Calculating in one-third-octave bands allows ODEON to represent frequency-dependent behaviour occurring within ranges narrower than a full octave band. This can be relevant, for example, when materials have strongly varying absorption characteristics across neighbouring one-third-octave bands.

However, most standardized room-acoustic parameters are derived from integrated energy-decay curves or energy ratios and are conventionally evaluated over octave-band frequency ranges. Reporting them in full octave bands therefore provides the resolution normally used for standardized assessment and comparison, while the internal one-third-octave calculations can still improve the accuracy of the underlying simulation.