Yes, I watched Alper do the "Air Test" of the Racer 2, and his results were close to those I got with a variety of coins. I have watched many 'Air Tests' on many Forums done by Keith Southern and many others through the years. I have seen 'Air Tests' done by different detector manufacturer's reps for decades, and I have done them myself since I built my first unit about March 5th of 1965. That's been a lot of 'Air Testing' and, along the way, a lot of learning.
Does an 'Air Test' show us exactly what we can expect form an in-ground target? .. Of course not.
Does it mean 'Air Tests' are useless and of no real value? .. Of course not!
If you were to go into a Dealer's shop and see three or four interesting looking detectors, and all of them had the same weight and balance, all of them used the same size and type search coil, and all of them had the exact same adjustment controls and visual display, then you would buy any one of them and expect to get the same performance, right? .. Of course not!
If you seemed to prefer one over the others because it has a more attractive colored control housing, and you liked silver rods instead of black, and a white search coil instead of brown or black, then just buy it. It's going to provide all the anticipated depth and performance you expect, right? .. Of course not!
So you grab a few coins out of your pocket and use your gold ring , then one-at-a-time you turn them on and check them out .... in an 'Air Test.
With one you can get some air-depth readings in the 8" to 11" range with an assortment of coins, and with another they tend to vary a little more depending upon the coin metal make-up, but give air-depths from 7" to 12". Then you check the 'air -depth' of the model that catches your eye and use the same coins in the same location with the same EMI potential issues and you get 'air-depth' readings from 4" to 6½". Is that one going to be the model that impresses you and you'll quickly shell out some good $$$$ for it? .... Of Course Not!
'Air Testing' simply shows the best possible depth results you might get in the most favorable conditions.
It allows you to learn more about the detector's modulated or saturated audio with different gain settings and coil-to-target distance.
It lets you learn about the detector's possible Target ID response 'depth.'
Learn about the detectors Tone ID audio quality, and at what approximate 'depth' you might hear an anticipated tone for the target and when there isn't sufficient signal strength to process a proper audio Tone.
It gives you an idea of how one model might compare with others, and is useful for learning much more other than simply potential 'depth.'
I 'Air Test' every make and model detector I have ever owned, and for good reason. THEN, having gained some knowledge and knowing what kind of best-possible results I might get in favorable conditions, I just get out detecting and learn all I can about the detector. Along the way, as I am searching different locations and trash target conditions, learning the adjustment functions and learning the quality of the audible and visual responses, I am much better off learning and mastering a detector, all because I started out with some learned information to relate it to ... thanks to 'Air Testing.'
Just my thoughts.
Monte