From the manual:
"5. Attenuator Adjustment
Independent, continuous variable attenuators are used for each unit to adjust the MF (mid-frequencies) and HF (highfrequencies) levels to the speaker's woofer level. Make adjustments appropriate to the reverb in the actual room, and to your liking. In general, for most speakers, it takes about 1 – 2 months after initial use until the unit's vibration system yields optimum performance. As the level balance is expected to initially change with use, we recommend that you readjust the level accordingly."
Neodymium 2213?