Space reserved for new recordings and comparisons to schneider disc setup.

In the meantime, he's a sample recording of the same capsules applied with a Schneider disc. Most of this isn't head on though. Obviously the guitar had better strings for strumming on back then (Elixir PBs).Featured in this recording is; Guitar (strum), Guitar (hybrid), Guitar (Finger pick), Tenor Saxophone, Cornet. Mostly recorded front-on and one shout so excuse sloppiness been a bit busy to maintain/develop them all.

Here's the temp mp3
https://app.box.com/s/gz8u1cb6rx8s7f98et6u
Bonus points if anyone can guess the group whose songs feature heavily

You can tell there is an absence of a hollow echo that the head current has.

Thanks

Thanks! I'll check the tunes tonite! Keep up the great work!

Oh, and sorry 'bout the new avatar... I couldn't resist.

This one is better 

Any ideas on what I should fill the head with? I have a spare sound damping foam that I can feed in there, but I wonder if stryofoam balls might be a cheaper and possibly better option (also easier to remove if I don't like it), as it would add more dead air space than open cell foam.

Listened using equalized Hifiman RE-400 IEM with custom "tips".

Without crossfeed:
The three left-to-right motions are nearly indistinguishable, there's no depth and almost no height to them. If I were to guess, first was front, second above, third behind the head, but all three sounded wrong, passing through head instead of around.
If I'm right the first two were circle-like outwards from the left/right ear, the depth is hard to describe, but sounds like 10-15 cm at most. Music samples of the first music are (counting from the ear plane) 90 degree - in front, 30 degrees tp the right, 30 degrees to the left, 60 degrees to the left? and again front. Cannot say anything about depth/distance. All samples sound in-head and very flat, much more than the original mix.
Original mix sounds a bit "widened stereo", but not in-head at all.

With crossfeed:
The original music sample sounds properly forward focused and close to the non-crossfed studio version in terms of depth retrieval. Much more centered.
Suprisingly, adding crossfeed to the head samples makes it sound kind of correct, first and second click being moving back and towards the ear about 1.5m (starting from the ear), third being in front close to the head - sounds very discontiguous, with a hole in the middle; fourth being in front further away?, less of a hole in the center; fifth being behind the head, sounds the most correct to me, almost no hole; The guitars are like sitting at a distance of ~1m in front, about 1m to the right; 1m to the left but closer, bassier?; right below the face or at it, in front.
Music also sounds much better, heck, I'd say better in some respects than the original sample via crossfeed - natural room-like reverberation - though it sounded like a bit of a V-shaped bass cut, too nasal with a hole in the middle.

All in all, I think the recordings do sound quite clean, so the capsules and recording environment are reasonably good. It is a very quiet recording though, needs a bunch of dB boost.

This would suggest that the head is highly ineffective in capturing crossfeed - the microphones not being omnidirectional enough, having a half-sphere directionality, not really omni? That or the head is not sonically permeable enough or is internally too reflective.
HRTF must be more or less correct, since with crossfeed front/back is fine I think. Height is uncertain, I'm not sure you've tested it at all.