FLAC, WAV, AIFF, DSD… There’s no denying that picking the right type of audio to listen to can be crazy confusing. And if you even dip so much as a toe into the world of digital music, you’ll be confronted with discussions about sample rates and bit depth and whether lossless FLAC files can ever match MQA for fidelity. No need to worry. It’s handled - thanks to our in-depth, completely straightforward guide to file formats. By the time you’re done, no weird acronym will ever confuse you again.
- Sample Rate And Bit Depth Explained
- MP3s vs WAVs vs AIFF
- OGG vs FLAC vs ALAC
- DSD Explained
- Listening To DSD
- MQA And Hi-Res Audio Explained
- Three Great DACs You Can Buy Right Now
- Video Breakdown
To understand how audio formats work, you need to understand two concepts: Sample Rate and Bit Depth. These are two measures that tell us how accurate a piece of digitally-recorded sound is, and we can understand them by imagining an art critic, looking at a painting.
Yes, an art critic. Work with us here.
Let’s say this particular art critic really wants to get to grips with the painting above, really understand it, but can only look at it a certain number of times before she has to move on (she’s busy, OK?) Obviously, the more often the critic looks at the painting - the more she samples it - the more she’ll understand about it.
Because she’s really, really good at her job, she can look at the painting 44,100 times a second. Obviously, if her sample rate was higher - say, 96,000 times a second - she’d understand more about the painting. (We’ll talk about why we picked those numbers below - for now, just roll with it).
Now let’s talk about the painting itself. Let’s say our super-fast critic is looking at a small part of the hills in the picture, which happens to be painted yellow. That’s a piece of information she now has. But obviously, because she knows art and painting, she knows that there are different shades of yellow - many, many different shades. So when she’s writing up her review of the exhibition, she’ll be able to describe that yellow section as, say, butter yellow, or lemon yellow, or gold. Not just plain yellow.
Let’s also say she’s reasonably smart, and has the ability to describe sixteen different shades of yellow. Each shade of yellow she can describe is a single bit of information, so in this case, she has sixteen bits of information at her disposal. Couple that with her 44,100 looks at the painting, and she’ll obviously have a very in-depth understanding of what she’s looking at.
(The analogy’s a little crude, because computers work slightly differently, and sixteen bits of information actually refers to 2 to the 16th power which is 65,536 volumes and…look, trust us, you don’t need to know this, OK? Let’s just go with sixteen bits of information. Sixteen shades of yellow. Breathe, everybody. Breathe.)
Now think of this in music terms. A group of musicians in a studio is the painting, and the software recording them is the art critic. The software ‘looks’ at the incoming sound 44,100 times every second, and is able to use up to 16 bits of information each time it does so, to describe what it’s hearing. Audio you hear on a regular CD, or on a standard Spotify stream, is 16bit/44.1kHz (samples are always described in Hertz, and 44,100 Hertz is always referred to as 44.1kHz, or kiloHertz). You could also record higher-quality audio at, say, 24bit/192kHz, which means that the software is sampling the music 192,000 times every second, and is able to draw on 24 bits of information to accurately describe it.
If none of the above is clear, then all you need to understand is this: the higher the bit depth and sample rate, the more high-quality an audio file is.
Let’s get MP3s out of the way first. Because they suck.
If you have even a passing interest in audio fidelity and decent sound, you’re going to want to avoid these. Essentially, an MP3 (MPEG-1 Audio Layer 3) is a file that sacrifices audio resolution for minimal size, cutting out all the bits that we as humans aren’t supposed to be able to hear, in return for delivering a file that is very low in size – and can be read by just about any device on earth.
The downside? We might not technically be able to ‘hear’ the bits that are cut out, but in our opinion, this compression of the file – and we’re going to be using the terms compressed and uncompressed a lot – renders it thin, tinny, and lifeless. No one these days seriously uses MP3s – so much so that its creators recently terminated its licensing, declaring it dead. All the same, you’ll still come across it now and then.
WAVs are equally common, and useful for anybody wanting decent audio. Essentially, WAVs (Waveform Audio File Format) are higher resolution audio files, that almost always contain uncompressed audio. Technically speaking, a WAV is simply a way of presenting a piece of audio that is in fact encoded with something known as Pulse Code Modulation (PCM), which is a way of taking analogue audio and converting it into digital so that it has a sample rate and bit depth, as described above.
Honestly? You don’t need to stress too much about the difference. For all intents and purposes, WAV and PCM are interchangeable terms, and both refer to a reasonably high quality audio file.
What about AIFF? This audio format (it stands for Audio Interchange File Format) is functionally similar to a WAV, in that uses Pulse Code Modulation to encode a piece of audio and present it in a digital format. Back in the day, this was Apple’s answer to Microsoft’s WAV, and it would only work on Mac computers. Now? They are more or less interchangeable. Put simply, if you have a file that is a WAV or AIFF, you’re dealing with a decent piece of audio.
For the most part, these uncompressed formats are used for actual files played through services like iTunes music libraries. You won’t really see them on streaming services, which tend to use special types of lossless, compressed audio. But we’ll get to that.
Now we get into the interesting stuff. As almost all music listening these days are done by streaming, it’s worth talking about file formats you’re likely to encounter if you use services like Tidal, Spotify, or Apple Music.
Let's start with the fun one: OGG, or Ogg Vorbis. No, we’re not making that up. That is its name. It comes from a character in the Terry Pratchett novel Small Gods, because every so often, computer engineers display a little bit of personality.
Think of OGG files like supercharged MP3s. They are compressed audio, meaning they get decent file sizes that are friendly to streaming over WiFi, but they also manage to avoid much of the audio damage caused by this process. Spotify uses them, and depending on how much you pay, you can get them in various different sample rates, from 96kbps on the free tier all the way to 320kbps on the premium. As a general rule, premium-tier Spotify audio quality is considered a perfectly acceptable, if not mind blowing, way of listening to music.
FLAC is where things get really interesting. The Free Lossless Audio Codec pulls off a remarkable trick by allowing you to compress the file size down to around 60% of the original, without losing any noticeable audio quality. Not only is it free and open source, but it allows the transmission of sample rates up to 1,411 kbps, which is significantly higher than anywhere else. This is the format of choice for the streaming service Tidal, and in terms of mass-market streaming audio, it’s considered the gold standard. This is what you will be listening to if you care deeply about your sound, and you don’t want to commit to physical formats like CDs or vinyl.
Finally, there’s ALAC (Apple Lossless Audio Codec). It’s not quite as good as FLAC in terms of efficiency, and arguably not in terms of audio quality, but you have to work quite hard to notice the difference. It’s the format of choice for Apple Music streamers.
You can divide audio formats into two categories: those that are more commonly used to hold actual audio files on hard drives (MP3, WAV, AIFF) and those that are used for streaming services (OGG, FLAC, ALAC)
DSD files are…different. IThey upends the rules of regular music. But as you’re about to find out, they are something you truly need to experience. You’ll forgive the fact that this section is slightly long, but it takes a bit of explanation. You can totally skip it if all you want to do is stream off Tidal.
A lot of articles on DSD spend a good deal of time going into the history – one we read recently even starts things back at the invention of the phonograph, which is eyebrow-raising, to say the least. Here’s what you need to know about how DSD was made. A while back, Sony and Phillips wanted to start experimenting with higher-quality audio formats, and DSD was what they came up with. There. Short and sweet. Obviously there’s a bit more to it than that, and you can dive into this article which explains it - it’s a but much for our purposes here.
Now, as we said, your regular CD or Spotify stream has a bit depth and sample rate of 16bit/44.1kHz. DSD Audio, however, has a bit depth and sample rate of 1bit/2.8224MHz (MegaHertz). In other words, a piece of DSD Audio is sampled 2,822,400 times every second, and each time, it only produces one bit of information.
Imagine a ruler with 44,100 lines on it. In other words, you can measure something in 44,100 increments. If the bit depth is sixteen, you’ll then be able to gather sixteen bits of information from the segment you’ve just measured. But if you have a ruler with 2,822,400 lines on it, then obviously you’ll be able to take much finer measurements, yes? And when you’re taking measurements that fine and that accurate, you simply don’t need sixteen bits of information. You only need one.
That’s because the segment you’ve measured won’t be all that different from the ones to the left and right of it. Having sixteen bits of information won’t be any more beneficial than one bit, in this case. When the sample rate is that high, there’s no benefit to having a higher bit depth. You can simply record that information as a 1 or a 0 - or, in sound terms, whether the amplitude of a sound wave is increasing or decreasing. By the time those 2,822,400 1s and 0s are put together, you have an insanely-detailed picture of whatever it is you’re measuring - as if you’d suddenly zoomed out of a close-up of a collage, where each tiny segment only differs slightly from the ones around it, to find it forms a map of the United States.
(Obviously, there is a lot more to it than this, but this is the simplest way we can think of to describe it).
2.8224MHz is far from the upper limit, by the way. You’ll frequently see terms like DSD64 and DSD128, which refer to DSD audio with even higher sample rates. The maximum, so far as we know, is DSD256+, which has a sample rate of 12.288MHz. That is completely stupid, and recordings in that format are so rare as to be practically non-existent.
In order to really understand exactly how it works, you have to be familiar with and conversant in not just concepts like bit depth and sample rate, but quantization, jitter, non-linearity, amplitude, noise-shaping algorithms and more. That is, to be honest, way, way more detail than most of us will ever need. If you want to find out more, there’s plenty of information elsewhere that goes into excruciating depth (here’s a vaguely-understandable explanation) but what you need to understand is this: DSD audio sounds really, really damn good. You’re in the room with the musician. You are standing right in front of him while he shows you what he can do. You are hearing each note in extraordinary, pinpoint detail. You stop listening to a piece of recorded audio on headphones or a pair of speakers, and you’re transported directly into the recording studio. You are mainlining pure music, snorting the goddamn motherlode, injecting three minutes of the best drumming you’ve ever heard right into your carotid.
We are not even a little bit joking. DSD is incredibly geeky, but holy hell, it’s worth your time. It’s the single highest-quality source of audio we’ve ever heard, and we’re not kidding when we say it’s left us breathless. Forget the maths. Forget the clunky examples. If you take one thing away from this guide, it’s this: a song playing back as DSD audio will be among the finest things you have ever heard, and you owe it to yourself to try it out.
So geeky, it needs its own section. Here goes…
To get it, you’ll need to not only invest in a DAC and amp capable of handling DSD, but you’ll also need a specialized player (we weren’t kidding when we said this was geeky). And there are a few downsides: The most obvious is that your favorite artist probably isn’t available in it. If you’re the kind of person who enjoys Norah Jones, Diana Krall, Carlos Santana, or indeed Steely Dan, you’re gold: there will be a DSD version of your preferred album available online, at stores like Acoustic Sounds. But if you like Kings of Leon? Kanye West? Taylor Swift? Arcade Fire? Any chart song released in the past decade? You, my friend, are out of luck. Right now, DSD recordings are overwhelmingly dominated by what one might charitably call legacy acts, and if that’s not what you listen to, you’ve got problems.
And even if you do, be prepared to pay significantly more for an album than you would if you bought it from iTunes – DSD albums usually nudge the $25 mark. They take up far more space on the hard drive, too, clocking in at around one to two gigabytes in size. And oh, by the way, don’t expect to be playing these things in iTunes, or on your phone. You need a specialised audio player to handle them. We use the free Pine Player on our office Mac, But by far the most popular one is Audirvana Plus, which costs an eye-watering $74.
Streaming? Ha. Oh, hahaha. Excuse us while we snort uncontrollably. That's just not going to happen - not for a very long time, anyway.
So, you’ve bought your audio and downloaded Pine Player. Did you think you were done? Sure, you could just plug headphones into your computer, and start listening, but let’s be real here. Listening to DSD Audio through your computer’s crappy digital-to-analogue converter (DAC) and terrible amp circuits is like getting a bottle of aged single malt whiskey, and drinking it out of a cereal bowl. Be nice to your music, and be kind to your ears. Invest in a DAC that can specifically handle DSD Audio, and you’ll ensure that what reaches your ears sounds sweet and accurate.
We give three examples of DSD-ready DACs at the end of this guide, but you can also see our list of the best DACs of this year. While you’re at it, you’re going to need a really good amplifier, too. And a really good pair of headphones.
OK - you can technically cheat, and up-sample a piece of PCM audio into DSD format. Amp/DACs Like the Sony TA-ZH1ES (full review here) actually have circuitry that remasters audio into DSD, up to 11.2MHz (which is a huge sample rate). And don’t get us wrong: it’s still very, very good. But if you want the full experience, your source recording needs to be DSD.
One of the things that streaming can’t do, and that actual files on a hard drive can, is deliver true high resolution audio. That’s a little bit of a nebulous term, encompassing a lot of things, but it essentially means audio of the very highest quality. We are a little bit dubious about manufacturers trumpeting their products as handling it, mostly because it’s so ill-defined, but it’s out there. And there’s been a development recently that might bring it to streaming services.
It’s called MQA (Master Quality Authenticated). Essentially, it delivers tiny files with absolutely enormous sound quality, using some sophisticated digital jiggery-pokery to package them into a FLAC or WAV container, and deliver them down your piddly WiFi signal.
On the one hand, this is obviously very good. On the other, it hasn’t quite taken the industry by as much storm as it would have liked. It still readily available, but it’s yet to make a real dent into the dominant file formats of our time. Although for the record, we would love to see it do so.
You can actually listen to MQA audio on Tidal right now, thanks to their Tidal Masters lineup on desktop. You also need compatible hardware to actually run it – like DSD, it requires some fairly specialised internal components to get it working.
Fortunately, these things are becoming more and more readily available. Products like Bluesound’s Pulse 2 wireless speaker and Meridian Audio’s portable Explorer2 DAC (full review here) will quite happily handle MQA sound.
We haven’t tackled every single audio format on the planet here – just the major ones. With this primer, you should very easily be able to distinguish between different types of audio, and make a decision that will vastly benefit your listening experience.
Digital-to-Analogue Converters are the piece of equipment that will be handling the transmission of your file types. All of the below will handle everything up to DSD, and they’ll all make a real difference to your sound.
We’ve yet to come across a simpler, smaller, more effective way of dealing with DSD audio. Optoma’s palm-sized little DAC Has a tiny light that turns blue when it detects the presence of DSD, and it outputs some pretty magnificent sound. It’s not going to trouble the big boys, but it’s an excellent entry point.
In our review, we said: “You could argue that it’s overpriced, that $200 is too much to pay for a device that hangs its hat on a file format that very few will ever hear. But who cares? Even without resorting to DSD playback, the uDAC5 is a simple, effective device, with almost no downsides. Just shell out for the thing already, and thank us later.”
We’ve got this absolute beast of an amp/DAC sitting on our testing shelf, and will be publishing a full review soon. What you need to know is this: it costs around $2500, can handle just about any audio format you can throw at it, can remaster any audio into 11.2MHz DSD (yikes!), and it sounds brilliant.
In the time we spent using it, we’ve been left in awe at just how clean and clear the sound is, with distortion so low as to be practically non-existent. It’s definitely an audiophile-focused amp, but if you’re serious about investing in your setup, and experimenting with DSD, it’s well worth looking at. "While the substantial cost may put some people off, and it’s only really worth investing in if you are serious about your audio," we wrote, "it’s one of the most rewarding amps we’ve ever tried. It has breathtaking sound, absolutely stunning clarity, the kind of thing we’d expect to pay a lot more for. Couple this with a good pair of headphones, and a decent source, and you’ll have one of the best setups we can think of. We didn’t expect it to be so easy-to-use, either, but it was, and we loved it all the more for that."
This is a DAC that takes a little while to get to grips with, with a number of interesting options and modes that require – no, demand – exploration. It’s another unit we have in for testing, and in the limited time we spent with it, we’ve had a lot of fun with its DSD capabilities.
From our review: "It pairs particularly well with other iFi products – we loved using it with the iCAN SE, which we thought sounded harmonious and clear when working with its sibling – but it pairs equally well with any dedicated amplifier, and will be a huge upgrade from any internal DAC. No debate on that."
We are working on a video explaining the different file types individually, but for now, here’s a very short breakdown about how DSD audio works. Seriously, it’s under two minutes, so you should totally watch it.