AirPlay disables iTunes EQ preset.

[bigpoppamac31]

So I came across this somewhat randomly. I am using a Bluesound Node 2i to stream music via AirPlay from my MBP to a headphone amp and stereo speaker amp. But I noticed especially with using headphones it did not sound very good. My headphones are the Sennheiser HD6XX (650) so they are very well regarded headphones. Somehow I got the idea to check the EQ setting in iTunes and I noticed that they were disabled. I could not turn it on and moving the sliders did not make any change. But when I turned off Airplay the presets came back. So I did an online search and someone mentioned a "workaround" by enabling AirPlay via the volume control in the menu bar instead of the icon in iTunes. That seems to "fix" the issue but when playing music like that there is definitely a delay of a few seconds when select a song to play and even more so if I watch a YouTube video. The latter can show the audio out of sync with the person talking on camera. So my question is why would Apple make this change and is there any intention from them to correct this?