It was a beautiful day so that I had to go out and shoot this outdoor video with the Sony SRS-XB33 against the Anker Soundcore Motion+ and also the Teufel Motiv Go at the end.
I didn't hear the intermodulation issues that much through my microphones like they appear here, but the Sony would have definitely benefited from some additional tweeters. It sounds fine up to 3/4 and is still usable at maximum just starts to distort with particular tracks and you need to readjust bass through the Music Center app. Turning bass to maximum was not wise for maximum volume, but it usually works well for half volume and above.
My current settings are: treble +10, mids +2 and bass -3 to -5 for low levels. For levels around half and above I just boost bass to +5 and with most "normal" recordings it sounds fine and clean up to maximum like that.
Unfortunately Sony still didn't learn how to make a speaker sound appealing for all volume levels and you need to readjust the sound for the given volume level on your own. But the XB33 definitely has some unique character and charm which I would like to demonstrate in my upcoming indoor videos.
With the current discount on amazon.de it is an extremely appealing speaker, just not really suitable as some "boombox", but rather for critical listening. The speaker is marketed wrong I would say.
So stay tuned for my upcoming videos, which should reveal its full potential.