Our partner Studiotec installed a new Ampetronic D14-1 inductionloop amplifier to Temppeliaukio Luthearian church in spring 2018. The induction loop signal is excellent in the middle of the nave, but there is 50Hz hum which may disturb some hearing aid users. Please switch on you low frequency filter in the hearing aid, if possible.
You can find detailed information from Temppeliaukio church in hereuhear.com.