Boz Digital Labs has released Mono Bass, a plug-in that they say fixes those pesky low frequency width problems by collapsing your low frequencies to mono.
A spokesperson told us, "Having a nice wide stereo spread is great, expect for when we are talking about low frequencies. Mono Bass fixes the wide bass problem by collapsing your low frequencies to mono. Just set your frequency, and everything below that is brought to the center. Most of the time the effect is quite subtle (or at least it should be if your mix isn't completely out of wack) but it definitely solidifies the low end and fixes a lot of the awkwardness of extreme panning on headphones. Just for added measure, we added a width knob to the higher frequencies."
Pricing and Availability:
Free until January 1st then $25.
A variable width bandpass filter and a voltage controlled mixer