Sheet Type

All Blank Calculation Sheets and Standard Calculation Sheets include a named range called SheetType. This is fed through the code to inform the macros certain information about where to copy cells, extend functions, include parameter fields etc. The Blank Calculation Sheets have the following SheetType values:

• OCT For octave band calculations, linear input
• OCTA For octave band calculations, A-weighted input
• TO For one-third-octave band calculations, linear input
• TOA For one-third-octave band calculations, A-weighted input

SPLSUM

Public Function SPLSUM(ParamArray Rng1() As Variant) As Variant

This function is called from other parts of Trace and can be used in any cell (even non-Trace sheets), once the add-in is installed.

The function loops through each element of ParamArray and uses the worksheet function Log10 to calculate the aaddition of each Sound Pressure Level. The main part of the calculation is:

SPLSUM = 10 * Application.WorksheetFunction.Log10((10 ^ (SPLSUM / 10)) + (10 ^ (Rng1(i) / 10)))

SPLAV

Public Function SPLAV(ParamArray Rng1() As Variant) As Variant

Calculates the average noise level, in the same method as SPLSUM with the extra line:

SPLAV = SPLAV + 10 * Application.WorksheetFunction.Log10(1 / n)

A-weighting

More fully explained by Wikipedia, the A-weighting is an attempt to correct a linear spectrum to the frequency response of the human ear. Originally built based on the 40 phon loudness curve, the A-weighting is now used for most noise measurements.

A possible substitute curve could be:

=10*LOG(((35041384000000000*E$6^8)/((20.598997^2+E$6^2)^2*(107.65265^2+E$6^2)*(737.86223^2+E$6^2)*(12194.217^2+E$6^2)^2)))