Kees de Visser

Thanks! A quick test in iZotope RX4 indicates that both measurements are very similar. I couldn't reproduce the HF roll off difference. Let's wait for others to do some testing.

But adding more money could make it two Ferraris. Although you can't drive them both at the same time, it might be fun to have them. Rather similar to those extra bits in hi-res audio.

The word "enough" isn't very popular amongst audiophiles, probably because it implicates a compromise

Those look suspiciously similar to Schoeps microphones as "Straus pairs": an omni and a cardiod microphone taped together to allow flexible adjustment of the polar pattern during postpro. The setup origined from the days when "wide cardiod" mics were not available and was named after the German Tonmeister Volker Straus.

I didn't say that and I suppose minimum phase SRC can be fine, but that can't be verified with this test, like you've pointed out.Main goal for a SRC (at least for me) is perceptual transparency. If that can't be achieved at the desired SR, then the "sounds best" will be the best option.

I'd feel rather uncomfortable when a preference (sounds best) is found, but no audible difference. To me this indicates one or more variables are missing.

I'm not looking for sound quality differences. I'm merely looking for any difference. With a decent SRC there don't have to be significant (audible) amplitude or phase differences below 20 kHz.

Do you think that those other factors will prevent the center image from moving, when it's expected to be stable, assuming no audible differences ?

The null-hypothesis is that there isn't an audible difference between redbook and hi-res, at least on perfectly linear playback systems. If the alternating signal results in a stable image with no perceptible displacement, that seems an indication (though no final proof) for inaudible differences.Some time ago I've noticed some distortion on hi-res material. When comparing them in an alternating test it became obvious that it was the headphone amp in my laptop clipping with the hi-res signal and not with the redbook one. Reducing pb level or inserting a separate headphone amp resolved this. It's just another tool in the test toolbox

Sorry, I thought the test was about redbook vs. hi-res audio. Pitch is an interesting subject, but I don't see the relationship with audio resolution.

I do that kind of testing quite often. Don't forget however that differences between transducers (L/R speakers or headphones) can be relatively large, especially compared to cd/hires differences (which are typically below -100dB). Also our two ears are not perfectly identical.What I sometimes do is open a redbook and hi-res track in a DAW, pan their Left or Right channels to the Left and Right DAW output and alternate them periodically (e.g. every second). If you notice an image displacement (lateralization) at any frequency, it's likely that there is an audible difference. Make sure to synchronize the tracks sample accurately and use inaudible (linear) cross fades, without dither. To illustrate, the signal becomes: Lch: L.lores - L.hires - L.lores - L.hires - L.lores - L.hires... Rch: L.hires - L.lores - L.hires - L.lores - L.hires - L.lores... Synchronization is important, since the human ITD (inter aural time delay) JND is known to lie around 10 µs, which is about 1 sample period at 96 kHz sampling rate. Also don't forget that many SRC's produce outputs with subsample delays compared to the original. I think 10 µs sync accuracy should be ok, but YMMV.

Thank you !

My wife just read in the French news that Qobus will file for bankruptcy if they can't find a take-over deal before the 16th of November 2015. Guess I've been too optimistic. Sad, I like their services.

Sorry, can't edit my post, which was in reply to Fridolin's dropout problem. Disabling gapless playback in the preferences solved it for me.

I've noticed that too. My guess is that it has to do with the "cross fade" option. If the transition between two tracks isn't seamless, the last second of the previous track is added to the next track. I think I solved that by disabling the cross fade. It's my second day on Qobuz so I'll check.