Can you detect any distortion due to the fact that one is front facing and one is side facing. I would think they could account for that by tweaking the relative volumes and the firing direction of the ear peace speaker, but have't read anything to that effect.I just did a side by side test: Identical track on a just-delivered iPhone7 vs soon-to-be-sold iPhone6: I find the volume to be about the same, certainly not drastically different between the two. But...the sound quality is considerably better on the iPhone7. Hard to put your finger on it, but a cleaner, crisper sound - probably the result of the stereo speakers.
Can you detect any distortion due to the fact that one is front facing and one is side facing. I would think they could account for that by tweaking the relative volumes and the firing direction of the ear peace speaker, but have't read anything to that effect.