They are not regular audio companies. You have the military and auto companies that did huge amounts of work in this area. A lot is contracted work to special engineering shops for serious expensive well run DBT testing. This is done not so much from the manufacturing side of audio to make sales (which it was for the auto companies) but just to get information for doing future research. The audio companies know some of this but pretty much all ignore it as it would kill any sales of any high end wires, interconnects or amps. There are bigger issues going on in audio.
I will talk about one easy issue. We are, as Amir and many other very good engineers know, very limited in our hearing compared to the extreme level of what we can test and measure. So I will make up the following example.
We measure speakers for how much of a voltage change to a speaker is audible, Lets say we find that it is .3 volt. Then we start testing other associated things like speaker wire. We find that in a 20 foot length of wire there is a .1 volt difference. We then start rating wires as voltage drop over a 20 foot length. We find that almost every wire made from .25 to $40 afoot all have between 0 and .1 volt drop. So, we can measure a difference very accurately but we have proven that anything under .3 of a voltage difference is not audible by anyone at any time. But, we still measure and report wires as the best being 0 volt drop and the worst being .1 drop. Everyone jumps on the wagon and has to buy the 0 drop wire as its "the best". In reality using either wire from the best to the worst makes no difference at all to what is audible. Then audio marketing steps in and all the high dollar wire companies advertise that you should buy their high dollar wire at $40 a foot as it shows 0 voltage drop. Plus the advertiser mentions, "everyone" knows (a lie) that the cheap junk wire that shows .1 of a drop sounds rough, veiled, and closed off. The expensive wire (that they are selling) opens up the soundstage makes it pristine and clear, you get downright amazing sound for only $40 a foot for wire. Forgetting that .1 is way below the threshold of anyone's ability to hear any difference.
Then people join in and say well, yes it isn't audible at all to have the .1 wire, but it is how the .1 affects the whole system. It affects the 40khz area of sound so it is most likely coloring what we hear. Even thought there is no way it is doing that. People just run with a "made up" theory and then everyone is back to "I must pay $40 a foot" or I will notice my highs are not right. NONE of the research shows that to be true. No one can hear it as proven by rigorous testing on and on. But the idea grabs hold in the marketplace and high dollar wires are are seen as some how better, when they are not.
So, in audio where snake oil is knowingly sold daily. Good companies start buying into some of the ideas. That is why I believe we should test everything and then decide if the results are showing any of it to be audible. Your brain, the single biggest audio issue, your room and speaker placement/angle have FAR MORE to do with good sound than any extreme measurement. Luckily on a site as rigorous in its testing methods as ASR is, "fooling oneself with BS" is kept to a minimum. Amir does a very good job on testing and letting the results speak for themselves. But we all need to keep our eyes open for weird stuff that tries to creep in, such as bogus theories etc. They are sneaky and so prevalent that they can sneak in if we are not on guard all the time.
