Thank you Francois. Checked the volumes using other viewer and they look OK:
I added another subject , here is the spectrum of the raw EEG data with obvious alpha peak:
Then ran the full OpenMEEG default options for Surface and Volume.
I then did Sources 2016, default options.
Then scout time series using the AAL as surfaces and then AAL as volumes, default options (mean, norm of xyz for volumes)
Computed coherence and looked at the spectra of those (right click Power Spectrum)
Here is a demonstration of the different spectrum issues (top is Volumes, bottom is Surfaces):
This lack of alpha peak is what I am seeing regardless of subject data, however sometimes the spectrum for the volumes is more uniform across frequencies depending on method used. Also, the PSD for the scout time series looks similar to the coherence spectra so it is in the Raw EEG -> Scout time series conversion that something isn't right. Either way, there is a big difference between the two spectra (surface and volume)
Any help greatly appreciated.
Thanks again