Will an angled enclosure effect the sound of a passive radiator?

@teo_audio - that is very interesting.  I would have responded that there shouldn't be much impact on an angled surface.  In fact, I would have thought that it would improve the issue with standing waves (as many speaker boxes have been designed with angled back panels instead of parallel back panels).  I would have commented that it's important not to create an area inside the box that is so constricted.  It's important to have a lot of free air space for waveform pressure.

The linked pictures relay upper frequency response issues related to edge diffraction and loss of bass response also due to diffraction. I am confused with the post’s reference to "resonance" and "in the box".
http://www.aes.org/aeshc/pdf/how.the.aes.began/olson_direct-radiator-loudspeaker-enclosures.pdf

I hear exactly what you are saying but, there are secondary concerns, and they have their explanations. Some of this gets into the lore of speaker design, and is generally tightly held as it is part of what can make a speaker company successful, vs reaching up to mediocre by chance. Clarity was purposely not there. :)

I’ll go back to lurking in any speaker discussions, and not increase or create confusion...

thanks guys for all your answers my project seemed to work with no major sound inconsistencies