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Interesting listening experiences with a few CD players

Is there scientific evidence that it's inaudible? Could you please provide Details?
I can't prove a negative. If it's audible then there will be evidence of such. No evidence of audibility means we can assume that it isn't audible until shown otherwise.
 

Note there are no listening tests with this. No demonstration that the issue is audible.

Possible I have missed listening tests elsewhere, if anyone can find some please link.
 
Well, I cannot provide evidence of audability. The knowledge of this issue alone, however, is enough for me to try to avoid it!
 
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Then there is nothing to discuss because there is no objective evidence here. How to perform a proper ABX test and why this is important is subject to various threads here: just search for it.

Edit for typo
There is clearly a lot to discuss for many of us. We're discussing.
 
There is clearly a lot to discuss for many of us. We're discussing.
Actually arguing, this is the way it goes when you kick off a thread claiming a discovery but providing no data.

Would have been good to first provide a set of measurements of the actual output of your machines, with the sighted and un-level matched listening test to accompany. Discussion might have ensued.

I notice the first response you got at your other forum was that you didn't do it right because you used FLAC files.:facepalm: So yeah, your approach is guaranteed to cause arguments in any forum. Data would have at least provided you a means to debug what is actually going on. Likely nothing, but we will never know in your case.
To each his own, I guess. I won't blind test for this one.
Of course you won't. You are looking for an argument, not a discussion.
 
I have a fairly extensive collection of CD players. Always found brand 'B' to be slightly softer, slightly less 'etched' - exactly as you, and your son,
have.

I don't discount sighted bias as the cause but it's possible that it isn't that.

Yes I'll buy that, but since that sort of emphasis really bugs me I've gone the other way with regards to the balance of my system.

Only Bassey I have is on a CD of Bond theme tunes, I agree she is 'challenging' :)
I have a Sony CDP-S1 'La Scala' player as part of my second rig. No issues via its digital output, but I'm convinced it very slightly 'softens' the audio output (it's very slight as 'heard' on headphones which get past my hearing issues better than speakers do). I also noticed when doing an A-B with the computer-DS2 feed, that the Sony is *very slightly* quieter. Manually (and totally unscientifically) trying to correct when switching, the 'softness' completely disappeared!!!

On the Main rig, I compared the Micro Seiki (via tranny-coupled balanced outs and Belden XLR-RCA cables wired the way Micro Seiki did their original (screen pin one floating at RCA end), to the SU1 via coax SPDIF and found the Micro Seiki player appeared to have a slightly more 'organic' bass. 95% of this I put down to the fact the Micro Seiki used this way had a very slightly *higher* output and maybe added bass distortion from the transformers. The fact that reverb tails and 'flutter echoes' in some mixes were easier to perceive consistently via the SU1 pulled me up short, made me grin to myself and I've now stopped again being anal and listening for 'deeeeetails' rather than the music (i don't have the bloody time to listen to the gear any more). Once I again attempted to match the levels, the 'differences' almost disappeared, what remained being in my head more, I suspect.
 
No, I was using the ADI2 FS Pro in preamp mode -- analog line level in, headphone out.

Unless I am mistaken, both the JDS Lab Atom Amp 2 and the RME ADI Pro FS have only one analogue input.

That means that it is not possible to make comparison between two sources through their respective analogue outputs, because you have to stop the CD, unload it from the CD player tray, close the tray, switch the Atom or the RME and the CD player off, unplug the modulation cables from the CD player, plug them to other other player, switch the Atom or the RME and the other player on, load the CD you just listened to with the first player in the second one, and then only listen to the new player.

The delay introduced by this procedure is way too long to make any meaningful comparison.

Furthermore, you wrote you make sure to level the volume by reading the dB scale displayed on the RME. But this display is not an absolute measurement of the RME output level. It is just a reminder of the setting of the volume control. If the two CD players have not exactly the same output level, the RME output level will also be different if the volume level is left unchanged, because in that case the RME apply the same exact gain to two already different input signal levels. Needless to say, it is simply impossible to ensure that both CD players were listened to at matched levels with the Atom, unless a measurement with a test tone on a test CD has been done to check that the volume knob is set such as the Atom output level is kept the same before proceeding to the listening, which would lengthen even more the delay between the listening sessions of each CD player.

In order to make a meaningful comparison, you should, at least, procure yourself a preamplifier that have two identical analogue inputs and the ability to trim the level on this inputs, or to memorize an offset of the volume control when switching from one input to the other. Any one of this features will be used to compensate the difference in output levels of any sources to be compared when playing simultaneously two items of the exact same CD release.
 
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I understand that the CD swapping introduces delays, so I accept that this is not real-time switching. The differences I heard are not that subtle that they'd only be audible in real-time switching.

Also, the dB scale reference was not to show that I level matched. It was just mentioned to show that I know what I'm saying when I said that I deliberately turned the volume up and down 2dB. The scale told me I was tweaking the volume 2dB or more.

This is huuuge deliberate gain change, and if I heard the differences even with this sort of change, I'm clear that the differences were big. Amir has done similar experiments with DACs where he deliberately changed the gain up and down, but he did it only 10%, not 2dB. And he was looking for very subtle differences. His testing had real-time switching, so that part was taken care of. A helpful FM on DIYaudio gave me a link to Amir's earlier work in another thread: https://www.avsforum.com/threads/establishing-differences-by-the-10-volume-method.1136745/ The title is "Establishing differences by the 10% volume method." I think Amir's method of deliberately tweaking volume is valid, and mine is too.
 
Then there is nothing to discuss because there is no objective evidence here. How to perform a proper ABX test and why this is important is subject to various threads here: just search for it.

There is no One True Definition of "proper", it's good to use our brains to try different methods to counteract biases. Were you aware of this work by Amir, circa 2009? https://www.avsforum.com/threads/establishing-differences-by-the-10-volume-method.1136745/ In it, he deliberately tweaked the volume of one source or other to help him GET RID OF BIASES and detect differences.
 
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Yes, will do, 100%. This is the most important next step.

(You too have an ADI2 FS Pro, I see. Kewl.)

A null test recording between two players will easily indicate whether there are differences between the CD players
 
Nice anecdote, but over the years and many cd players, not my experience at all. I'd think the level matching and blind testing might be enlightening if properly done.
 
Isn't such a thing hard to do? One will have to time align and level match the two samples rather accurately, I am not sure I have the skill. However, I'll record and publish FLAC files here from the A2D process.
 
Nice anecdote, but over the years and many cd players, not my experience at all. I'd think the level matching and blind testing might be enlightening if properly done.
Did you listen only on speakers or on headphones? I'm discovering this difference because I now have good headphone amps and very clean IEMs. I'm not at all sure I would hear these differences in an average room even with very good amps and speakers. I wasn't expecting to hear this, as is clear from my starting post.
 
Desirable cd players but all the more desirable if you also have the original box and user manuals. It is soooooo nice to have the original box. We should do a comparison of the boxes; some boxes are better than others.
 
Did you listen only on speakers or on headphones? I'm discovering this difference because I now have good headphone amps and very clean IEMs. I'm not at all sure I would hear these differences in an average room even with very good amps and speakers. I wasn't expecting to hear this, as is clear from my starting post.
Not a fan of headphones. Plus comparing them is problematic. Doubt it is the player/dac that is particularly different based on my experience over the years. Your preference is one thing....
 
Isn't such a thing hard to do? One will have to time align and level match the two samples rather accurately, I am not sure I have the skill. However, I'll record and publish FLAC files here from the A2D process.
For this you use DeltaWave. Doing it in audio programs won't work simply because of clock drift.
Ensure you record the exact same excerpt and at least 1minute of it.
It has a learning curve.

Easiest would be to simply post 3 files and let some of the guys that are well versed with this program do their magic.
 
Desirable cd players but all the more desirable if you also have the original box and user manuals. It is soooooo nice to have the original box. We should do a comparison of the boxes; some boxes are better than others.
I personally have a preference for double boxes,such as solid weighty sound,sometimes slightly overblown!

Thin boxes,always screechy and sibilant.
 
Not a fan of headphones. Plus comparing them is problematic. Doubt it is the player/dac that is particularly different based on my experience over the years. Your preference is one thing....
I too am not inclined to listen on headphones if I get speakers as an option. I use earphones always whenever I want to focus on checking the sound quality of the source media or source component -- it removes the (relatively imprecise) speakers and room from the path.

I've recently bought good headphone amps, and I always had a good pair of reference monitoring earphones (ER4PT), now I have 3 more pairs, so this chain is absolutely superb to let me "look into" the music.
 
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