My issue with DBT is really an issue with AB tests in general (sighted or otherwise) when comparing essentially neutral components (like cables, DACs, sensibly designed amps) which have, as near as damn it, the same distortion, frequency response and any other traditional measurement of quality. I’m not claiming this is particularly scientific, but dexter3d you did ask earlier, so here goes...
I think everyone agrees that our response to music is affected by all sorts of mind tricks, of which placebo is a very significant one. But there are many others that come into play based on a combination of 4 parameters (expectation, memory, imagination and circumstance). Now our minds are incredibly clever at using these parameters to get a satisfying emotional reaction to sounds of the most appalling quality – e.g. noisy shopping mall with grossly coloured sound system. But this great strength is also a weakness that so easily can confuse us.
It’s my contention that I can overcome placebo (with the only reliable test I know: listen to unchanged system for months, then change just 1 component) easier than I can overcome all the other mind tricks that occur with AB tests. For example, if I suddenly notice a new sound when listening to A, then I’ll forever hear that sound on A, but also on B as well. Does that mean that B is identical to A, or that I’m just forever hearing that sound because it’s now come to my attention?
Of course, my only reliable method is often impractical, and so I have to compromise with all sorts of AB situations at home or at the dealer. That’s life and I just have to rely on experience as best I can. Now, just add the tiniest bit of stress into the equation, and I’ve frequently not been able to tell A from B on components I KNOW are different. It’s incredibly easy on such occasions to get into a complete muddle, so that I can no longer tell the difference between A and a giant pink giraffe.
I’m not saying it’s impossible to do an accurate AB or DBT test and I’m sure one can be trained to overcome the mind tricks and stress. Now, I have the highest respect for Nick Charles and his carefully thought out cable DBT tests. However, his results merely confirm my concerns about such tests. Did he prove there was no difference, or did he succumb to the mind tricks? Being confident of his results is no guarantee that he overcame the mind tricks. And a test that can successfully spot tonal, volume and gross distortion differences is not guaranteed to also spot the differences between essentially neutral components.
Another issue I have with AB tests is that, even when you do spot a difference, it tends to be minimised such that you can’t judge whether that difference is of long term significance and whether it is worth the price difference between A and B.
Wavoman, re your offer of SB v IG. Yes I accept. Life’s too short not to grab such opportunities with both hands (did I just say that out loud?).