16 bit vs 24 bit vs 35 bit vs 36 bit vs 64 bit DAC sampling


I have limited knowledge about DAC's, but as I understand it, a typical CD player used to have 16 bit sampling, and supposedly no one was supposed to be able to hear the difference between anything more than 16 bit sampling; however, I recently purchased an Esoteric K-01X, which has 35 bit sampling (why 35 bits? no doubt only to differentiate it from their then top of the line 36 bit sampled Grandioso series).  

Now I can hear a big difference between my old Musical Fidelity kW DM25 DAC with 24 bit sampling (circa 2005), and the newer Esoteric DAC with 35 bit sampling, although I'm not supposed to, although maybe there are some other electrical programs playing with the sound besides the sampling rate.  

Now, there are 64 bit sampling DAC's, and I'm wondering how much the ear actually does hear from the sampling, or if it's something else entirely that's making the digital sound better?  

Any insightful opinions or perspectives?  

Thanks.
drbond
They do some processing at higher bitrates. If they have a digital volume control it is better to start with 32 bits than 24 since they will basically throw away bits later.

Other processing than volume is possible and there it is also better to start with more bits.

For sampling frequency it is usually the filtering you want to improve. They need to have filters and the filters affect the sound quality. If they start with 96kHz the filter hopefully only affects a part of the spectrum we can't hear.

There are articles about this If you google. For everyone saying that you can't improve the signal from what was as input that is actually wrong. You may make it worse but you can calculate more samples in a way that it probably improves the sound for most music. You just need math and a very fast processor. The Chord MScaler does this if I am not mistaken. 
What does it sound like? If the new DAC is better does it matter how they got there? I have several DACs, do they sound the same, definitely not. 
That you hear a ’big difference’ may stem from the fact that the analog circuitry behind the two DAC's is different, or that the digital audio processor uses some kind of filtering or effects to create a certain ’sound profile’.

There’s no difference to the human ear between 16 bit sampling or more bits, since the only change is the dynamic range / noise floor. The other parameter is sampling frequency ... higher frequencies can reproduce more higher harmonics of instruments, but since most people can’t hear much above 16kHz there’s not much sense in that either.

Higher rates are used in studios for mixing purposes, where signals are being treated in the digital domain with filters and effects like reverb, phasing, tube sims, limiters, compressors and what have you.

It can even be hard to hear a difference between uncompressed and compressed digital audio. Do this test to determine if you can hear the difference:

https://www.npr.org/sections/therecord/2015/06/02/411473508/how-well-can-you-hear-audio-quality
I use a Pioneer  CD player (PD-F1009) which is s a 1 bit DLC machine, circa 2000 and rolls 300 + 1 cds all day long. Granted this is in an outdoor system for background music by the pool but everyone loves the sound.  Could it be better? Sure, but for me why go there $$$$.
Yes 16 bits is plenty I agree.

But the sampling rate is much more important.
As every high school math graduate knows, the wave form of digital sampling is a jagged zig-zag saw, like an endless flight of stairs.  The little triangles at created by joining the teeth of the saw is a measure of the departure of the digital representation from the true waveform of the sound or, rather, the music you want to listen to.

The higher the sampling rate the smaller the little triangles and the closer you get to the original sound.

Of course, if you want the original sound, you have to listen in analogue.