I just came across this interesting 2013 Gearslutz thread - Foobar 2000 ABX Test - Redbook vs 192/24 showing positive ABX results & wanted to post it here as a sort of repository for ABX testing
What I found interesting in it were the descriptions of the listener, Ultmusicsnob (who seems to have recording & mixing experience) & his honest reporting of the ABX process.
What come across is the difficulty & dedication required to find the "difference" even though he already heard a difference in sighted listening.
Things like:
What I found interesting in it were the descriptions of the listener, Ultmusicsnob (who seems to have recording & mixing experience) & his honest reporting of the ABX process.
What come across is the difficulty & dedication required to find the "difference" even though he already heard a difference in sighted listening.
Things like:
"Keeping my attention focused for a proper aural listening posture is brutal. It is VERY easy to drift into listening for frequency domains--which is usually the most productive approach when recording and mixing. Instead I try to focus on depth of the soundstage, the sound picture I think I can hear. The more 3D it seems, the better. "
"Caveats--Program material is crucial. Anything that did not pass through the air on the way to the recording material, like ITB synth tracks, I'm completely unable to detect; only live acoustic sources give me anything to work with. So for lots of published material, sample rates really don't matter--and they surely don't matter to me for that material. However, this result is also strong support for a claim that I'm detecting a phenomenon of pure sample rate/word length difference, and not just incidental coloration induced by processing. The latter should be detectable on all program material with sufficient freq content.
Also, these differences ARE small, and hard to detect. I did note that I was able to speed up my decision process as time went on, but only gradually. It's a difference that's analogous to the difference between a picture just barely out of focus, and one that's sharp focused throughout--a holistic impression. For casual purposes, a picture that focused "enough" will do--in Marketing, that's 'satisficing'. But of course I always want more."
"I tried to listen for soundstage depth and accurate detail. It took a lot of training repetitions, and remains a holistic impression, not any single feature I can easily point to. It seems to me that the 192 files have the aural analogue of better focus. To train, I would try to hear *precisely* where in front of me particular sound features were located, in two dimensions: left-to-right, and closer-to-further away--the foobar tool would then allow me to match up which two were easier to precisely locate. I know it muddies the waters, but I also had a very holistic impression of sound (uhhhhhh) 'texture'??--in which the 192 file was smoother/silkier/richer. The 192 is easier on the ears (just slightly) over time; with good sound reproduction through quality headphones (DT 770) through quality interface (RME Babyface) I can listen for quite a while without ear fatigue, even on material that would normally be considered pretty harsh (capsule's 'Starry Sky', for example), and which *does* wear me out over time when heard via Redbook audio."
"Practice improves performance. To reach 99.8% statistical reliability, and to do so more quickly (this new one was done in about 1/3 the time required for the trials listed above in the thread), I mainly have to train my concentration.
It is *very* easy to get off on a tangent, listening for a certain brightness or darkness, for the timbre balance in one part, several parts, or all--this immediately introduces errors, even though this type of listening is much more likely to be what I am and need to be doing when recording and mixing a new track.
Once I am able to repeatedly focus just on spatial focus/accuracy--4 times in a row, for X & Y, and A & B--then I can hit the target. Get lazy even one time, miss the target."
It took me a **lot** of training. I listened for a dozen wrong things before I settled on the aspects below.
I try to visualize the point source of every single instrument in the mix--that's why I picked a complex mix for this trial. I pinpoint precisely where each instrument is, and especially its distance from the listener. Problem is, both versions already have *some* spatial depth and placement, it's only a matter of deciding which one is deeper, and more precise. I've tried making determinations off of a particular part, like a guitar vamp or hi-hat pattern, but can't get above about 2/3 correct that way.
The better approach is just to ask myself which version is easier to precisely visualize, as a holistic judgment of all the pieces together. Equally effective, or rather equally contributing to the choice, is asking which version holistically gives me a sense of a physically larger soundstage, especially in the dimension extending directly away from me--thus the idea of listening to reverb characteristics.
Having to listen to four playbacks (A/B, X/Y, for one choice) gives rise to the problem of desensitization. Neurons naturally give decreased response to repetitions, so I've found I can target my answer more easily if I pause 5-10 seconds between an A/B (or an X/Y). Otherwise, A/B is always easier than X/Y.
I have rather junky monitors, KRK Rokit 6's, so I'm kind of surprised I can get a result out of them. To get down into low single digits I shifted to my headphones pushed by a nice Schiit Asgard2 amp, which I just acquired--if your headphones are good, I'd recommend using them for the testing. This is more for isolation than anything else.
Summary to this point:
The effect being heard in foobar ABX testing here has been robustly detected:
1) In popular music (2 different songs), dense textures
2) In classical music, more transparent textures
3) With default iZotope SRC values (32 filter, 175 alias suppression)
4) With "highest quality" SRC values (150 filter, 200 alias suppression)
5) Using high quality headphones through high quality headphone amp out of high quality interface (RME Babyface)
6) Using cheap earphone plugs driven by generic motherboard audio chips from garden variety [Dell] desktop PC
NOTE: The above results contribute ***nothing*** to the established science of 192/24 versus 44.1/16 and human hearing.
They do establish that whatever I am detecting in these file pairs is robust to a wide range of conditions: equipment, program content, and SRC algorithm settings.
They do establish that when I say, "It sounds better to me", I am reporting a provable reality, not a placebo effect.