Wouldn't a simple crossfeed suffice to get a stereo-like image? That is implemented in many dac/amps I think.It would be more simple to advertise “speaker-like sound,” but Axel has been veeeery careful to not promise the moon. Since the left ear still cannot hear what the OAE1’s right driver is doing at any significant SPL, there’s no true “In-Front Localization” that will happen JUST because of the headphone. People who would hear “speaker-like” marketing might assume IFL would be there, and even though the soundstage is great it still doesn’t sound like there’s a phantom center out in front of you (unless you use a DSP, like I said in my review).
So, by managing expectations, Axel has been uncommonly genuine and transparent about the benefits and goal of the design. “I” personally do whole-heartedly recommend using it with a Spatial Audio DSP though! Thankfully those are becoming more and more common these days You can force the (better than nothing but not “wow” for me) Dolby Atmos headphone DSP in many streaming apps these days (like Apple Music and Tidal) and devices may have Spatial Audio too (PlayStation 5 has its bespoke DSP, I believe Xbox Series has Dolby Atmos too).
If I followed what you and Axel have explained correctly and the goal was not to create a speaker-like experience, I still don't understand what the goal actually is. What Axel is saying the quote I posted above makes no sense to me. Yes, our ears play a role too shape the sound, but the result of what that sound means to us, is still subjective. Our ears don't EQ the FR so it always sounds great. That's not how ears work.
I am not too sure about these spatial audio algorithms, I don't really see a benefit for music with them. No normal concert has surround sound.