The story so far.
I remember when I was in the university many years ago and we were testing the speed of reaction of a particular enzyme. I remember my frustration when the predicted reaction would not show in the empiric experiment. I did not know what I was doing wrong and I was very upset indeed. A Doctor from the Biochemistry department laughed at me and told me what an ass I was. I was using the technique perfectly fine with no flaws, the problem was that the technique itself had its limitations. That happened about 15 years ago and I have never forgotten the lesson about the scientific method.
My first approach for this test has been: first test the tester.
I am pleased to say that my hearing works very well from about 31.5-40 Hz to 20 kHz. This is a complete surprise for me because I was not expecting to hear beyond 16 kHz. I suppose my loath to discos and crazy decibel leves in bars has paid off in the long run.
When you read other very interesting reviews, you just put your faith in the tester and how good their hearing is. Well, I do not have any reason to suspect that it is not the case, but it is probably better to test. So I did. For my hearing I used the AKG K601 (being the more lineal headphone I have, it makes sense) and I used the 8 fold oversampling with the first filter in the Stagedac (according to the manual, with this combination, the pulse response is a sin(x)/x function and the frequency response is practically lineal. I want to mention here that the manual that Jan has written is extremely good and clear. I never read manuals but I have read his from first to last page).
I have been through the following tests:
1Left-Right
2Left, Right, Center, Surround (like Dolby Pro-Logic)
3Dual Tone 700 L, 1k R 0dB 30s
4700 0dB 30s
51k 0dB 60s
6Log Sweep 20 to 20k, 0dB to -6dB, 32s
7Linear Sweep 20 to 20k, 0dB to -6dB, 32s
880Hz warble +-40Hz -1dB 60s
9100Hz warble +-40Hz -1dB 60s
10120Hz warble +-40Hz -1dB 60s
1116 -1dB 30s
1220 -1dB 30s
1325 -1dB 30s
1431.5 -1dB 30s
1540 -1dB 30s
1650 -1dB 30s
1760 -1dB 30s
1863 -1dB 30s
1970 -1dB 30s
2080 -1dB 30s
2190 -1dB 30s
22100 -1dB 30s
23125 -1dB 30s
24160 -1dB 30s
25200 -1dB 30s
26250 -1dB 30s
27315 -1dB 30s
28400 -1dB 30s
29500 -1dB 30s
30630 -1dB 30s
31800 -1dB 30s
321250 -1dB 30s
331600 -1dB 30s
342k -1dB 30s
352500 -1dB 30s
363150 -1dB 30s
374k -1dB 30s
385k -1dB 30s
396300 -1dB 30s
408k -1dB 30s
4110k -1dB 30s
4212500 -1dB 30s
4316k -1dB 30s
4420k -1dB 30s
45Piano A4 440Hz
46Piano solo, stereo
47Drum solo, stereo
48Digital Metronome 120bpm 4mins
49Crest Wave 10s
Rather than using a tone generator, I have burned the Wav files from the Michael "Bink" Knowles website. Michael is a very generous Audio Engineer that allows anyone to download his own audio test files (you can download free at:
Michael Knowles: Audio and Video Production).
With this first basic test I can confirm now two things: First, the DAC seeems to works as reflected in the manual (so I can infer that Dr Jan Meier is an honest man, which is not always the case with other companies of Hi-Fi) and second, that my hearing is very good. This is a very good start indeed.
With that in mind, I will move to phase two: testing the DAC section. For the record, I haven't found any significant difference between Coax and Optical so I will be using the optical connection for the tests. Unless otherwise stated, I will use the HD650 because of popular requests!