Yes I have, Saturn. When I first got into the more expensive equipment and moved out of the Best Buy arena, several of the sales people tried to sell me on expensive cables and bi-wiring. Being a EE and fully aware of how the signal was being transmitted, I wasn't about to buy their word on it. I had them switch them out without me able to see what they were doing and I told them not to speak while doing it. It's not as good as double-blnd but certainly better than spending $2k and convincing myself I heard a difference to justify my purchase. Neither cable sounded appreciably better to me at all.
I then turned it on the sales people. Neither of the two that had been trying to sell me on were able to even pick the cables out beyond blind guessing and they were never consistent on what they prefered.
As such, I turn it around on you. Have YOU ever done a double blind?
