For those interested, DIYAudioheaven reviewed these here: https://diyaudioheaven.wordpress.com/headphones/measurements/hifiman/edition-xx-massdrop/ One of the things mentioned was a passive filter to tame the treble spike. I bought one of these filters from DIY and it does a nice job as advertised. I highly recommend it for those who own this awesome headphone. It cost me about $30 bucks US for the connector.