A couple thoughts interjected...
No one as of yet knows why the Schroeder Method works, least of all me! I claim no pedigree, only curiosity leading to the discovery and implementation. Speculation would be expected until such time as a cable manufacturer would chase down the explanation, if measurable.
Yes, I have done it with both RCA and XLR with analogue signals, as well as AES/EBU (XLR) in one setup from transport to DAC. I also have successfully done one RCA setup of Schroeder Method between preamp and amp. NOTE: ALL PREVIOUS WARNINGS AND CAUTIONS APPLY; this is a "do at your own risk activity". It should be avoided with certain amps, as has been forewarned, as well as some DACs that output from the chip (ie. No opamps) etc. Again, check with your equipment mfg. Or designer as regards safety.
Imho, the Schroeder Method is a system cost saver, not a money waster. Double the price of the materials and 4 splitters is a gift given the result in every instance I have done. Others who have tried thus far seem to agree. I certainly don't mind a perceptual $10K component upgrade for the cost of one more pair of interconnects, or doubled pair. :)
Finally, funny how everyone, even designers find their pet reasons for cable performance. My most consistent benefit in cables across prices and brands has been, aside from conductor material, heavier gauge. Consequently, the idea for the Schroeder Method grew out of many years of pushing heavy gauge cabling in rigs and getting what is to my ears better sound. Ymmv
