Just thought I'd share a flexible, inexpensive t-bar that provides mic spacing of anywhere from 0 - 40 cm. It's really just 2 KM235 bars joined together. It was inexpensive for me because I already had everything except the 2nd KM235 bar. Full parts list:
(2) KM235 t-bars
(1) locking / jam nut
(1) Bogen Rapidapter w/ 3/8"-male tip
(1) 3/8"-female > 5/8"-male thread adapter (tallish)
See attached for pics of it all put together. The bottom KM235 bar doesn't need a jam nut since the base of the Rapidapter basically performs the same function. The jam nut's used to orient the top KM235 bar so it's aligned with the bottom one. Spacing between the mics is then controlled by the two joints on each "arm" of the T. Packs up small enough to drop into a gear back pocket, which I particularly like as I'm trying to keep everything pretty compact these days. Going to keep my eyes open for a nice compact way to do the same, but extending out to ~50cm. One of these days...
Anyway, this new thread spurred on by a discussion in another thread (see below).
I have had great success with the Williams techniques
I've really enjoyed applying my learning from the Stereophonic Zoom (and with which I continue to experiment). In order to increase my options beyond the limited spacing of the Vark bar, I've combined a pair of KM235 T-bars so I have the option of up to a ~40cm spread (though I typically use the Vark bar for 0 - ~20cm). It's basically 2 x KM235 bars + a jam nut + a Bogen Rapidapter / thread adapter. Cheap, compact way to achieve wider spacing, especially if one already has a KM235 bar (as I did). I'll post pics if people are interested. The longer bar is great for situations in which I need a smallish SRA, allowing me to increase spacing and reduce included angle in order to minimize angular distortion and reverberation. Fun stuff!