It’s the holiday season, the time where most revolutionize their tech atmosphere with new devices sporting fresh batteries and some of the latest advancements to be had. Maybe you finally got that Android or Apple accessory, that shiny one you have held out for to have all year long. If it was a Bluetooth headphone of some kind, then you have come to the right article to read.
You see, Apple removed the headphone jack in the iPhone 7, followed in suit by many other Android manufacturers there after. Thus began a new avalanche. The money mudslide of the decade, where Bluetooth headphone sales probably exploded, fueled by the ever-greater selection of cheaper models now available to the consumer. These headphones generally use a technology with Bluetooth 4.0+, and provide anywhere from 6 hours (for earbuds and smaller accessories) to 15-40 hours (for on-ear or around-ear designs.) By far, Bluetooth 4 gave us something needed badly in wireless headsets: Lower-powered designs which take 10-15 minutes to recharge a few hours of operation at minimum. A typical headphone (like the Bose SoundLink on-ear, the first one in 2014 to slowly begin this trend) utilize a 4-500MAH battery for the 20 hours of playback it gets. Even noise canceling models such as the Sennheiser Hd4.50 pair provide >20 hours of ANC (active-noise-control) in parallel to Bluetooth use on 600 MAH, a battery no larger than found in a single household AAA battery. Remarkable, but it’s technology.
Not all Bluetooth headphones are made equal, and thus the fun begins.
If only I could end the story here at the happy bit, where we now have this great new generation of wireless tech with long-lasting battery life and just the most futuristic feeling ever imaginable by humankind. Not so. Great variation exists not only in Bluetooth versions supported, but also codecs supported by both earphones and devices you connect them to. A codec (the words encode and decode shortened) is simply the format your shiny new headphones and phone use to communicate together with.
Not only this, but another dimension of complexity gets added when we factor in supported Bluetooth profile versions. Because Bluetooth is like a layered onion with multiple levels of protocols, device makers have built a wild-west market where which specific ones they’re using are most-times unknown. Have you noticed, for example, that some Bluetooth earpiece headsets deliver sound quality similar to that of an AM radio, or that when your stereo headphones switch to a phone call, the quality of the sound is severely degraded to AM quality? This is because the 1.5 version for the headset profile (HSP) which had the horrible AM-quality sound was first, but a later 1.6 change allowed an upgrade of sound to 16-bit hd-voice quality audio. In my experience of using many bluetooth headphones over the year, only 2 (the Bose SoundLink on-ear and Sennheiser model) had this 16-bit quality call quality, many others (including Plantronics BackBeat Fit, BackBeat pro/pro 2) used the old-fashioned AM-quality when switching over.
There is one mistery solved, then: If you are looking for Bluetooth which does not downgrade microphone quality to what you may be used to from the past, try to look around Google to see which eadset profile it supports. If you see 1.6 or above, then you can safely say that the accessory supports hd-voice quality. This level will still be a slight step down from stereo Bluetooth audio, however containing a richer set of frequencies than an old mono radio. On the phone side, most modern electronics will support this natively, as the upgraded profile came out around the time of Bluetooth 3.0 in 2009. This means that headset makers have had nearly 10 years to make sure only the upgraded stuff comes out, yet I regularly see high-end headphones with truly the worst in microphone noise and quality.
Comparing Codecs: APTX, LDAC, AAC, what?
If that last bit of title sounded like a bunch of nonsensical characters to you, it’s quite alright – and I will spare you a brief word of advice if you don’t want to read into the technical know-how on how this works. Basically, if you get your music from Spotify, Apple Music, any streaming service, the quality of audio you get is limited by what is known as a lossy codec. Lossy simply means that during compression, minor details in audio are omitted in favor of size. To most with an untrained ear, the subtle differences are only minor to hear, but many professionals swear by only listening to uncompressed or lossless audio only. If you belong in the former group and just want convenient music access on all your devices through a flat subscription, then the type of Codec supported by your headphones won’t make any difference in audio quality to you. If you are in the latter camp and only get CDs converted to uncompressed flac files, you will very likely notice gains by using a higher-quality Bluetooth codec.
The Double whammy: when you’re encoding twice, you know you’re wireless.
Another downside of Bluetooth audio is that no matter what, your headphones must receive digital audio and translate it into sound you hear. This on top of your music already being lower in quality from being compressed. When a song plays, your phone downloads the digital audio in a lossy .ogg (for Spotify) format, and then your phone sends this to your headphones in its negociated codec. Wired headphones use a cable to transmit uncompressed analog signals to your ears, thus less of a bottleneck exists.
The Good News: Sony comes to the rescue
Ah what the world would be like without Sony always coming in to save the day. As luck would have it, their format wars extend to Bluetooth codecs as well, and the old legacy lives on. Sony’s tech is known as LDAC, and it can transmit audio at a wapping 990KBPS. Available on Android devices with Oreo and above, along with Sony-branded headphones. It’s an adaptive codec, meaning that the farther you go from your music source, the lower audio quality you can expect. Still, for Bluetooth, this is the highest we can currently get in transmitting sound. But let’s continue with some other codecs created over time to combat the problem of audio quality I was mentioning earlier. Snag this one in your standard Sony noise-canceling headphones and with a Google phone. You can check which Codec for Bluetooth is being used in the developer options section of settings, if you dare to venture there.
Along comes Apple, with their AAC
AAC is another codec supported on some headsets. (Bose, for example, and Beats.) It is an Apple standard, and delivers slightly higher in quality than regular Bluetooth may. As a lossy format, it’s kbps limit is around 250, thus comprable to a mid-range MP3 file in quality. Again, most people not paying attention to subtle acoustics wouldn’t notice a difference between this and Sony’s version.
Somewhere in the middle: APTX
When we look at APTx, it’s by far the most common standard advertised this year on headphones. In 2015, it was rare to buy a pair with APTX advertised, but today I’m seeing it marketed on many headphones trying to distinguish themselves in this increasingly cluttered market. APTX comes in two flavors, APTX and APTX HD. Another subset known as APTX low-latency. Most headphones I saw this year had low-latency APTX, including Plantronics and the other models I mentioned throughout this article. Bose is the only exception to this, as even their quiet-comfort 35 headphones don’t have APTX but stick with AAC instead. I’m not sure what their deal is. APTX-HD is something virtual unheard of yet, as I have seen very little effort by companies to brand audio gear with this marketing yet. The difference? Expect APTX to deliver around 352 kbit/s, 48 kHz / 16 bit LCPM audio, and for the hd counterpart to score higher around 576 kbit/s. Again, those listening to uncompressed music will notice that biggest gains, although APTX is still a lossy codec.
SBC, available everywhere, not to be confused with that now-merged telephone company we once had in the US…
SBC stands for sub-band codec, in our situation. It’s mandated that Bluetooth headphones implement it, so at the minimum you will get this when you’re using a stereo headset. It only supports around 192 KBPS audio, and by far can remove some important details from music when carefully listening for that bassline. However, it’s still stereo, and with many MP3 files the differences have already been removed enough for people to make a big deal of it. Some may notice a characteristic “swirl” sound to SBC, as this has been around since the original launch of the Stereo headset profile.
If you had burning questions about why Bluetooth audio sucks, I hope that I was able to answer them here. If you wanted to know where it’s headed and what is happening in the world of Bluetooth codec wars, this is your piece. All in all, these formats were established only because Bluetooth, by design, is a communications medium, not an audio one. This makes a huge difference in how it was designed, and it fulfills a great purpose in today’s world of connected cars and speakers. Yet companies over the years created variations to address some of the greatest challenges Bluetooth still comes with today: The variations pairing different-generation devices together can sometimes create. Windows 10’s Bluetooth stack is still a horrible one, and I could write an entire piece detailing where it really drops the ball in connection and quality. There’s even an NVDA Add-on created just for Bluetooth which tries to keep the audio channel open so that the headphones would not go into their low-power mode. I mean how aweful is that! Yet iOS and Android can provide better latency through Bluetooth stacks designed well. iOS, to my knowledge, does not support APT-X or LDAC, although Apple’s Macbooks computers in general should, so as long as it has a modern Bluetooth version. You know what though? Apple could quietly deliver APT-X support through an iOS update, and we’d never know. That is but the elusive nature of what we know today as Bluetooth.
Update 1: Some readers have pointed out that newer Bose headphone models may have APT-X support. A tech-radar review of the original QC35 indeed does mention that the QC35 II model has APT-X, so if you have one of the newer ones sold, you may still have higher-quality audio.