Scale Spectrum

There are two types of spectrum scaling available in the Power Spectrum and Wavelet Matching/Transfer Function windows:

Relative Scaling is accomplished by examining all spectra for the highest amplitude spectra value. This frequency is set to zero decibels and the other two curves are displayed relative to this scale.
Individual Scaling determines the highest amplitude spectra value for each curve, sets this frequency to zero decibels, and displays each curve scaled individually.

Click on the arrow under Scale Spectrum and select Relative or Individual from the drop-down menu.