cheapest cable upgrade ever

Well, there is no conventional basis for this idea. For me, perhaps the fact that batteries contain a metal case. When placed close to the cable conducting a high-frequency signal creates a sort of ferrite-like choke that can have an effect on some high-frequency signals (including digital audio carrier range) and have a low-pass filter effect on them. As I think was mentioned before here, batteries are not static electricity devices (so there is no static electric field influence) nor they are creating any other field since there is no current flowing (except the one discharging disconnected batteries in time).

Regardless, I used (3) AAA batteries, and fixed them with a rubber band evenly around the end of a silver-conductor USB cable (which is typically considered the "harshest: sounding, so I could expect most of the sound "smoothing" mentioned here) with the polarity-oriented as advised here. In short, I had no audibly distinguishable result from it so far. I am almost afraid to mention here that in my setup I hear differences between almost all USB cables I try.

Please notice that this idea is interesting not because I can explain or discredit it, but because I have an interest in phenomena that exist which do not have a good explanation, at least for now. For now, let's face it. no conclusion can be achieved, not certainly here (except through a formal double-blind study). It's certainly worth mentioning that how batteries work is still being investigated today, including their mysterious self-oscillation property mentioned here, which may or may not have anything to do with this topic: Dynamical theory for the battery's electromotive force - Physical Chemistry Chemical Physics (RSC Publishing)

Checks date. Nope, not April 1.

tksteingraber's post motivated me to try this. A single battery was placed on the ends of all cables, including the power cord of the network switch. First thing I noticed was a reduced noise floor. Secondly, the system gravitated towards how it sounds well after midnight. Yes, when your system can sound intoxicating. I was surprised by all of this, as I was expecting nothing.

So a big thank you to antigrunge2!!!! This is indeed the "cheapest cable upgrade ever".

Finally got around trying this on my BNC clock cables as well: works! having done all signal and clock cables now I feel I get much better impulse and spatial rendition

i took all of these batteries off my speaker cables and just one AAA battery on my USB cable into the DAC. sound was too compressed and too much high end and edge