Blind Testing

When I first discovered the effect of BlackDiscus, I was hugely skeptical. After all, here was something that really should not work. I spent several weeks testing the effect and then I decided that I needed to Blind Test them to really prove to myself that these things are real.

Blind testing has a bad name in audiophile-land. I think the main reason is that it exposes too many unfortunate truths - namely that a lot of things just don't do what they claim. Of course, audiophiles claim that blind testing introduces too much stress into the test and thus it's invalid. One thing is indisputable - if something passes blind testing, in other words, if a difference can be perceived under blind test conditions - then it really does do something. The arguments arise because blind tests are run whose results suggest no difference, but many hear differences. In some cases this is because the blind test is badly conducted.

Having done more blind testing than most people, I can see both sides, but I tend to go with the scientific idea that blind testing is good. But in reality, I don't get very different results when sighted and blind testing.

Since that first blind test (which of course I passed, or you would not be reading this), I have conducted several tests. If I call them "double blind" I am sure that someone will argue with me. But they are double blind in the sense that neither the person conducting the test or the person under test knows the identity of the device(s) being auditioned.

In this example, we will blind test a single BlackDiscus. To do this, we first create a dummy BlackDiscus that is inactive as it has not been through the vital processing stage. Thus is looks the same, feels the same and weighs the same, but it's been marked to identify as a dummy (it's even made from the exact same material).

So we have one real and one dummy BlackDiscus. Now this is made somewhat easier by virtue of the fact that BlackDiscus work fine if they are inside an envelope.

How we test

1. We get an assistant (who is otherwise not involved) to place the real and dummy BlackDiscus into envelopes and seal them. They are then placed in the test room. 
2. Now the test conductor mixes the envelopes. So does the test subject (both out of sight of each other doing this). Then the conductor marks the envelopes A and B, folds them up and tapes them to facilitate attaching to headphones.
3. At this stage, neither the tester or testee knows which envelope contains the real BlackDiscus.
4. The tester explains how to attach the BlackDiscus, how to put the one that's not being tested in a small tin, how to play music on the system.
5. It's then up to the test subject to listen to the two different envelopes (which are placed on the headphone's jack plug) and make their decision as to which is which is the real BlackDiscus. The tester remains to ensure that the test subject doesn't try to cheat.

I have personally been tested more than a dozen times and easily passed them all. I've also tested others. So far nobody has failed to detect the real BlackDiscus. In fact, most subjects say that it was very easy, and take less than 10 minutes to complete the test.

I've done blind testing of Interconnects before, (including one test where the so-called scientist running the test decided to mess with the data to further his own beliefs) and I can tell you that it's much harder to pick interconnects blind. It's possible, but requires a lot more than 10 minutes. Or it does for me at least. But when I blind test BlackDiscus I can pick it almost instantly. Sometimes, if I happen to choose the dummy to listen to first, I say to myself "it's the other one"

I invite others to try blind testing BlackDiscus - I think you will confirm what I see when I blind test them. 

How to Blind Test BlackDiscus Samples

What you need:

- one or two sample BlackDiscus
- a coin or some object of similar size/weight
- a couple of small envelopes
- an audio system. 

How to set up the test

Firstly you should wrap the BlackDiscus and the dummy (coin?) in some paper or kitchen towel, so that they are the same size. Mark the "rough" side of the BlackDiscus on the paper, and make a similar mark on the coin wrapper.
You then hand both to an assistant, along with two envelopes. The assistant should place one in each envelope, seal them and mix them up, and give them back to you. Instruct the assistant to place the marked side towards the "address" side of the envelope. This is so you can tell which way is "up" on the BlackDiscus.
At this point you can mark the envelopes A and B. Now neither you or your assistant knows what is in which envelope. You can fold the envelopes so they are not much larger than the original, making it easier to attach.
You can now trial both envelopes and see if you can hear which one sounds best. Before you open, get your assistant to witness you stating which one you think is the BlackDiscus.

How to trial

With a single device to test, it's probably easier to do this test on headphones as you can put the envelope on top of the headphone's jack plug. If you want to test on a speaker-based system, here are some places you could place the envelopes:

- if you use a coaxial digital link, or USB digital link (e.g. from digital source to a DAC) then place on this, at the digital source end. This will not work on optical cables.
- if you can get into your power amplifier, put envelopes on top of mains transformer
- attach to the power cord of your amplifier, DAC or digital source (this technique is less reliable than others)
- put on one channel's speaker output (ideally you'd put on both, but we only have one to test right now). This should make enough difference to hear.

We are interested to hear your results!