On most decks, you can set the recording eq to iec but to have it playback correctly, you need to have your playback eq set to iec. If your interested in iec for the Tape Project tapes only, you need to have the playback eq set. The best thing though, is to have it set for switchable nab and iec. Some machines, like Revox/Otari, already come this way. I don't know how involved changing the record eq would be ( Stellavox and others are qualified to answer that question) but compatibility with other machines here in the US would be drastically reduced. NAB and IEC aren't called standards for nothing.