Harald Bluetooth was a 10th-century king of Denmark. In 1997, an Intel engineer who’d been reading about Scandinavian history proposed borrowing Harald’s nickname for a short-range wireless standard that was then under development within the tech industry. Harald was picked because he is recorded as unifying Denmark and Norway, much as the Bluetooth technology was meant to unite the phone and personal-computer industries. But in the way the public can’t seem to make up its mind about Bluetooth, it’s also fitting that this particular king shares space in medieval lore with a fictitious prince of Denmark, the one immortalized by Shakespeare as Hamlet.
To listen on Bluetooth or not to listen on Bluetooth? That, if you’ll forgive the obvious reference, is the question that many music fans have been asking lately. The issue was brought to a head in early September, when Apple announced it would be doing away with the traditional headphone jack in the iPhone 7 and releasing new wireless headphones called AirPods, which are powered by Bluetooth technology and boosted by an Apple-formulated W1 chip. But Bluetooth audio is hardly just the concern of Apple users. In fact, Bluetooth headphone sales recently overtook non-Bluetooth for the first time, according to market research firm NPD Group. The clever old king has extended his rule.
The ascendance of Bluetooth for music, though, has drawn criticism. “I would not use Bluetooth,” Apple co-founder Steve Wozniak declared in August. “I don’t like wireless. I have cars where you can plug in the music, or go through Bluetooth, and Bluetooth just sounds so flat for the same music.” From the tech press to alt-weeklies, qualms about Bluetooth audio quality seem to be hardening into conventional wisdom.
Are Bluetooth’s critics right? The answer, as with so many aspects of audio equipment, is “it depends.” On a purely technical level, the amount of sonic information that can pass through traditional Bluetooth is less than through wired headphones or even a Wifi connection, meaning lower-resolution audio. So, yes.
But newer Bluetooth variants can allow more data to pass through, providing for sound that can be near CD-quality. What’s more, the decision between Bluetooth and wired or Wifi headphones is only one variable among many that can affect sound quality, audio experts say. In fact, the shift towards Bluetooth may be best understood in the context of music’s growing convenience, which has usually but not necessarily coincided with a loss of audio fidelity.
“Having these kinds of conversations seems more theoretical than anything else,” says Michael Greco, global brand director for audio equipment maker Sound United, which sells wired and wireless products alike. “There’s not a general rule.”
OK, but let’s get theoretical. If you listen to song you know well side-by-side on Bluetooth versus a properly wired setup, you’ll notice an unmistakable drop in quality, Greco and other experts tell me. “You don’t have to be an audiophile to hear the difference,” he says. Anyone who has heard a classic record at a high-end audio store and who also uses a Bluetooth device can probably recognize this as true.
That said, the amount of music lovers whose daily listening occurs via the kinds of stereo set-ups that populate high-end audio stores is fairly small. Even among those who do, what about when they’re going for a run? Wireless headphone sales are up for various reasons, Brad Russell, an analyst at market-research firm Parks Associates, tells me, including lower prices and longer battery life. “More importantly,” he says, “customers are purchasing multiple pairs of headphones to accommodate different use cases.” So you might listen to one set of headphones while working out, and another on a long flight.
But here’s the thing: In the types of places where wireless headphones would be most useful, a higher resolution level might not even be noticeable. The gym, the car, the subway, a busy street, a packed day at the beach—each adds a high level of ambient noise. “You couldn’t hear the best quality even if you had it in most of the situations where you’re listening to audio over Bluetooth,” Sound United’s Greco adds.
And yet “to Bluetooth or not to Bluetooth” isn’t the only quandary facing listeners concerned about audio quality, of course. “There are so many moving parts,” says Brian Lickel, who works in sales at Needle Doctor, a Minnesota-based audio store that specializes in turntables. “If the file you’re playing is not a high-quality file, or even just not a well-recorded song, then you’re also at the mercy of that.” Different headphones or speakers offer different levels of sound quality. With wired connections, going through a headphone jack, USB, or lightning connector can also affect the sound; as can variations in digital-to-analog converters, which turn the digital data on a phone or computer into an analog signal that can be heard through headphones or speakers. Every link in the chain can change the way music sounds.
Bluetooth technology itself has come a long way. What is Bluetooth, exactly? It’s a standard for transmitting information via radio waves over a short distance. Officially begun in 1998 by then-giants like IBM, Ericsson, Nokia, Intel, and Toshiba, Bluetooth was so hyped at first that it turned into the butt of what passed for jokes: On January 1, 2000, The New York Times wrote that Bluetooth “will allow you, theoretically, to call your Palm Pilot while riding in a taxi, if you can think of a reason to do so.” Which must’ve been a sick burn in Y2K. In just a couple of years, though, seeing businesspeople jabbering into headsets like crazy people talking to themselves was no longer so uncommon. Before very long, Bluetooth was familiar from wireless computer keyboard and mice, as well as from hands-free calling systems in cars.
Where Bluetooth wasn’t (yet) was in high-end audio equipment. When music and Bluetooth were mentioned in the same breath in the early 2000s, it was usually as a way of loading music onto a player—not streaming wirelessly from the player to headphones or speakers. “Music is different from voice,” as the entrepreneur behind one would-be Bluetooth killer said in 2004. Phone calls, he explained, could be expected to suffer occasionally from poor reception, “but if you're listening to a Creative Nomad MP3 player or an Apple iPod on headphones, you won’t tolerate your audio breaking up.'” (Aww, 2004.) By the end of that year, however, the first stereo Bluetooth headphones hit the market. Believe it or not, they were called the i-Phono, and they won praise for their “rich” sound.
Like a certain Danish prince seeing his father’s ghost, that praise may have been a wee bit delusional. If you think of Bluetooth as a pipe that data flows through, it’s a narrow one. The technical specifics can get pretty complicated, but Bluetooth offers much lower bandwidth—a skinnier pipe—than Wifi, let alone a direct connection. So Bluetooth, like MP3 files, relies on audio compression, in this case a type called SBC, short for “low complexity subband coding.” Compressing audio means it can fit through a smaller pipe, but at a point it also means losing some of the audio content. And that’s on top of the already-compressed files typically available for downloading or streaming.
Some spin-offs of Bluetooth can up the bandwidth for music in a major way. One of the most common is Qualcomm’s aptX, which uses a different type of compression to result in audio that aims to be “CD quality” and by most accounts gets close. But both the audio player and the headphones or speakers need to be aptX-compatible. And not all manufacturers’ devices are compatible with aptX. It doesn’t work with iPhones, for example. Potentially, though, other advances in technology could keep improving sound quality to new Bluetooth devices. Recent versions of Bluetooth at least theoretically permit data speeds of up to 25 Mbps; for an over-simplified comparison, the standard for CD quality is 1.4 Mbps. The upcoming Bluetooth 5 should be faster still.
In practice, though, not everyone who uses Bluetooth will be listening on pricey new headphone models from Bose or Sennheiser. For every listener exposed to higher-fidelity options when confronted with possibly buying new wireless gear, many more will be snapping up the cheapest speakers from big-box stores.
In some ways, I want to be OK with that. It doesn’t seem fair to complain about music’s shrinking prominence in the culture while expecting people to listen in ways that aren’t affordable or convenient for them. Music should be accessible to as many people as possible, right? Truth be told, the lo-fi indie-rock or ringtone rap in my music collection doesn’t exactly necessitate top-flight playback equipment. Audiophiles have been grumbling for years about MP3s, earbuds, and then streaming, but higher-resolution options like Neil Young’s Pono seem to have remained a niche market. And wasn’t Phil Spector’s Wall of Sound famously meant to carry over the limited-resolution AM radios and jukeboxes of its time?
But at the same time, doesn’t there have to be a point where music’s fidelity gets so compromised that it’s harder to enjoy as music? We’ve compressed it, then we’ve streamed it, then we’ve put it through tiny headphones—and now we’re gonna add another layer of compression so it can travel wirelessly? I don’t know where it stops. With sound quality the level of a flimsy flexi disc? A scratchy 78 RPM shellac record? That Thomas Edison, “Mary Had a Little Lamb” shit? There is, Needle Doctor’s Lickel cautions, “a danger, where people are settling for less. We have the ability here to play people their favorite music on a proper system. It’s a song they’ve heard a million times before, but it’s like they’re hearing it for the first time.” It’s one thing to want music to be accessible to everyone, but how accessible is it if they can’t really hear as the artists intended? Finding the right balance between convenience and quality is no easy task.
What constitutes “quality,” too, is highly subjective when it comes to music. Is there something rotten-sounding in Denmark? If we’ve learned anything from the debate about whether vinyl “sounds better,” it’s that making distinctions about audio fidelity is, for most of us, both tricky and a matter of personal preference. There’s the rub.
