For Your Edification and Enjoyment re "Burn In", etc.

Thank you Douglas, very daring of you to publish that here. I like people who are willing to expose themselves to ridicule. My experience agrees with you whole heartedly however, there is one problem. An anecdote does not a study make. This is an opinion piece. I believe your opinion is correct but that is only my opinion. The "numbers" are not large enough to be able to draw a conclusion with certainty. It is a start for those with influence to come forward with these opinions. The manufacturers are loath to do it out of fear they might scare away market share. They tend to support the mythology.

There are people who sincerely believe they hear improvements in sound quality coming from various tweaks and break-in. They deserve a solid explanation for this result but, when you try to explain the plasticity of human hearing and audio interpretation you lose them or I lose them. I am not the best at explaining these things. Perhaps you could do an article entitled "You Only Think You Are Hearing What You Hear."  

Thank you for your prolonged reply Doug. Again, no argument from me. I look at the manufacturers of such things as scam artists even if they believe in what they are doing.

Cable Cooker? I just returned from Audio Excellence's web site. Everything they make can be done in a home workshop with simple tools. None of it requires an education. None of it has a sound basis for operating as advertised. I think you should review the Audiodharma. Who buy's the equipment you review? Hopefully not you! 

Every human ear has a mechanism of accommodation. A tiny muscle, the stapedius, tightens up the ossicles in response to louder sound. The reflex is rather slow. It can not respond to impulse noises like gun shots. As it responds to louder music the sensitivity of the ear decreases but this varies with frequency. The end result is that treble and bass increase disproportionally to midrange at louder volumes. Add to this our poor audio memory, perceptual changes that occur with mood and other psychological factors and you have...a mess. Humans in general are very poor at analyzing the quality of audio information. They can tell you what they listened too and in gross terms tell you what it sounded like but they can not remember in fine detail what they heard. They can not reliably identify a single system out of a group of systems. What they hear changes with too many variables to be able to predict.
In order to be remotely reliable comparisons have to be made in rapid succession and repeated multiple times. Evaluations are relative. If a person's system is bright a system that is neutral will sound dull and so forth. What is normal for one person may not be to another. No method of calibration is used so you have no idea where a person is coming from. 

Douglas is right about switching phase in a system. I am not sure though what would happen if you ran 180 degree out of phase channels into an oscilloscope. Interesting to try. 
@russ69, I hate to tell you this but the last thing you want to trust is your ears. Human ears and perception are not trustworthy in this regard. None of us can make the claim of having trustworthy ears. This is exactly why more rigorous testing methods are required to come to any reasonable conclusion. It is also the reason for the popularity of "Tweaks" It is also the reason many of us do not have to hear an item to know the claims are false such as the cable cooking thingy Douglas mentioned. The claims made for it are downright stupid. They embarrass themselves with such rhetoric demonstrating that they have no idea what they are taking about. Don't be shy. Call things out for what they are. I want my system to sound it's best like anyone else but I refuse to spend money on silliness when there are so many things to buy that might or will make a meaningful improvement. In evaluating equipment never trust your first impression. repeat the comparison over and over until you are sure. When you are not sure of a difference assume there is not any. If you can set up an AB comparison then by all means. I have several ABX boxes that I made in the early 80's that run on 12 volt relays and a push button switch that is not marked in any way. I have no way of knowing what side is on.