  High degree solar mode frequencies as measured by ring diagrams are known to
change in the presence of the strong magnetic fields found in active regions.
We examine these changes in frequency for a large sample of active regions
analyzed with data from the Michelson Doppler Imager (MDI) onboard the SoHO
spacecraft, spanning most of solar cycle 23. We confirm that the frequencies
increase with increasing magnetic field strength, and that this dependence is
generally linear. We find that the dependence is slightly but significantly
different for active regions with different sunspot types.
