Imagine I said, "You should watch my special Blu-ray copy of Star Trek because mine is encoded with extra ultraviolet and infrared data and that totally makes it look better!"
At best you'd think, "My TV doesn't display UV or IR so it won't make any difference since I can't see those frequencies anyway." At worst you'd be concerned about getting a sunburn or a heat rash.
Now imagine I said, "You should listen to my special audio version of Miles Davis's Kind of Blue because I re-encoded it from the masters with special ultrasonic data and that totally makes it sound better!"
At best you'd think, "My amplifier filters out inaudible sounds so it won't make any difference." At worst you might even worry what pumping all this extra audio data into your speakers could do to them.
The thing is, this second example isn't hypothetical. What I've described above is happening right now as companies like Neil Young's Pono are telling people that audio files encoded at a bit-depth of 24-bits or a sample rate of 192kHz sound better than the 16-bit, 44.1kHz versions of the same audio on playback (recording is different, and we'll get to that later).
This difference between 16-bit/44.1kHz audio and anything greater than that has been tested (a lot... in double-blind tests) and we have yet to find any human that can reliably notice that difference. Bit depths greater than 16 bits and sample rates above 44.1kHz simply don't matter as long as the data is converted properly (and the industry's ability to do that conversion has improved substantially since those very first CDs were released at the dawn of the digital music era, though most of us at home don't have the skill or setup to convert and downsample properly).
Bit Depth and Sample Rate Explained
A digital audio file's bit depth determines its dynamic range (the difference between the softest portion and the loudest portion). 16 bits gives us 96 decibels (dB) of range. 24 bits give us 144dB. As per the aforementioned double-blind testing that's been done no human can hear that difference.
The sample rate of an audio file determines the frequency range that can be reproduced. Nyquist-Shannon sampling theorem informs us that perfect fidelity reproduction is possible with a sample rate equal to twice the maximum frequency we wish to reproduce. This means a 44.1kHz sample rate can reproduce frequencies up to 22.05kHz. Most human children can hear from about 20Hz up to about 20kHz. As we age the high end of that number narrows very quickly. Again, double-blind testing confirms all of this.
Science Prevails Over Emotion
There's a lot of science behind what we're discussing here. Nyquist's theorem has been proven by others many times over (hence the reason that many others' names are often attached to it). If this article instills in you the need to reconfirm all of this on your own (and you'd be in the good company of this author and several recording-industry professionals if it does) the only way to do it is to utilize a tool that allows you to perform your own double-blind testing (ABXtester, available for free for both iOS and Mac, works great). Without double-blind testing you (and I!) are quite subject to confirmation bias. Our minds are not objective when we have too much information.
There's also a ton of pseudoscience here. Earlier this month at CES I had Bruce Botnick, the producer of The Doors' LA Woman, tell me that after listening to a 24-bit album he feels better than he does after listening to the same album at 16-bit. That's great for him, folks, but doesn't mean much to rest of us. Also, Bruce is busy working with Neil Young to convince us all to buy their 24-bit Pono player, and I'm sure Bruce feels better after each Pono pre-order, too.
The truth is there is the potential to store more data in a 24-bit/192kHz file than in a 16-bit/44.1kHz file. You can see it if you just compare the two – the former will be many times larger than the latter. If you were playing this to a dog, for example, that creature might well be able to tell the difference (because dogs can typically hear higher frequencies than humans, so it makes sense to use a higher sample rate for music targeted towards audiophile dogs). If you're like me and will be playing your music for humans, though, we haven't yet evolved our ears where anything above 16-bit/44.1kHz matters upon playback. That's why it was standardized for compact discs at the beginning of the digital audio era, and that's why it still works today.
Music is Emotional, and That's a Good Thing
Music isn't just a listening experience. Music is also very much an emotional experience. If you believe your speakers are better than your friend's speakers, you're going to be happier listening to music at home. There's nothing wrong with that. I might like the band Weather Report (I do); my wife might hate them (she does). It's simply personal preference and we're both right.
Similarly, if you've convinced yourself that 24-bit or 192kHz (or both) sound better you are quite likely to believe you hear a difference when listening to music in that format. There's nothing inherently wrong with doing something solely because it makes you happy to do it. Just don't confuse that for science; and please don't try to convince others with pseudoscience. That's the last thing we, as a people, need.
Next, head to page 2 where we address the recording process, mastering, why Pono is great, iTunes and more.