Headphones

Just got my Q5k yesterday and was doing some listening thought BT when I noticed something different about my audiobook that I usually listen too. The recording sounds more spacious and less intimate, like there is a reverb / echo that wasn't there before and he's recording further from the mic.

I sort of noticed this when demoing music, but it was very apparent when I listened to the audiobook. I plugged my headphones back into my Atom stack and the effect was gone, then I tried the Q5k while wired with usb and it was also normal.

I expected BT to compress the signal a bit, not add characteristics to the sound, is this something common that I'm noticing? Maybe it's the MK3's making it easier to hear the difference.