StruttTools|Interpolate 1/1 Octave Level to 1/3 Octave interpolates a row of 1/1 octave sound levels to a 1/3 octave row, which is entered into the active row of the worksheet.
Strutt prompts the user to browse for a row of 1/1 octave data to convert to 1/3 octaves, and checks to see that the selected row is a 1/1 octave row. Strutt will convert the target row into 1/3 octaves and display it in the active row.
Strutt linearly interpolates the 1/3 octave values between adjacent 1/1 octave levels. The resulting spectrum shape is then shifted up/down in value to ensure that the resulting 1/3 octave spectrum adds up to give the same 1/1 octave levels as the original 1/1 octave spectrum, using the same calculation method as for the 1/3 Octave Level to 1/1 Octave calculation.