From their patent for the tech used in its $4k big brother the qol
"8: The objectives and advantage of the present invention may also be achieved through an audio signal reproduction method that involves, among other things, selecting a discrete signal source having left and right signal inputs, summing the left input signal and an inverted right input signal to produce a left–right difference signal, summing the right input signal and an inverted left input signal to produce a right–left difference signal, and summing the left and right input signals to produce a left+right summed signal. The method and circuit further involve adjusting the gain of the left+right summed signal, adjusting the gain of the left–right difference signal, and adjusting the gain of the right–left difference signal. Still further, the method and circuit involve summing the gain adjusted left+right summed signal and the gain adjusted left–right difference signal to produce a left audio output signal, where the ratio of the gains associated with the left+right summed signal and the left–right difference signal at least approximates the golden ratio [1 plus the square root of 5 divided by 2, or 1.618, equivalent to 4.18dB]. Similarly, the gain adjusted left+right summed signal and the gain adjusted right–left difference signal are summed to produce a right audio output signal, wherein the ratio of the gains associated with the left+right summed signal and the left–right difference signal at least approximates the golden ratio.
"9: The audio reproduction method of claim 8, wherein the gain of the left+right summed signal is asymmetrically adjusted relative to the gain of the left-right difference signal, such that the ratio of gains is within 10 percent of 1.618; and wherein the gain of the left+right summed signal is asymmetrically adjusted relative to the gain of the right-left difference signal, such that the ratio of gains is within 10 percent of 1.618."
It's a variation of the Blumlein Shuffler, which allows adjustment of a stereo soundstage's width and dates back to the 1930s.
By converting a conventional stereo signal into Sum and Difference signals and amplifying or attenuating the Difference signal before rematrixing these signals to produce left and right outputs, the stage width can be reduced or expanded. And if you change the spectral balance of the Difference signal, you can selectively alter the stage width at some frequencies but not others.
You can experience the effect of the Blumlein Shuffler for yourself on Jriver or Foobar etc by using a free mid-side VST plug-in ( http://www.voxengo.com/product/msed/
), I installed it and played around with mid-side levels. I found that a small increase in side level (between 0.8 and 1.2 with this plug-in) did help the soundstage bloom on many recordings. Too much level and it sounded too phasy and exagerated. But when set to a tasteful level, it works very well.Edited by Ari33 - 1/21/14 at 1:14pm