If there’s one thing we’ve learned over the years, it’s that plenty of people will happily sacrifice audio quality for convenience. Take wireless headphones, for instance. Although rarely a match for a good pair of wired headphones, they are mighty handy.
Recently, however, there has been a conscious push back for quality. The vinyl resurgence has demonstrated that to an extent (it certainly isn't convenient), as has the rise of high-resolution audio. So, is there a way to have ease of use without sacrificing performance?
The folks at Qualcomm think so, and to that end they have come up with aptX HD, launched at the start of the year, and bringing 24-bit hi-res audio to wireless music. In a nutshell, Bluetooth devices such as portable speakers have just potentially got a lot better.
But what's so good about aptX HD? How can you hear it? And what devices are compatible? Read on...
What is aptX Bluetooth?
To understand what aptX HD is, we need to discuss what ‘classic’ aptX is. It is an audio coding algorithm created in the 1980s, popular with film studios and radio broadcasters. These days, aptX is synonymous with Bluetooth, which you’ll find on plenty of computers, smartphones, AV receivers, and plenty of other consumer electronics products.
What’s the big deal about aptX? Its party trick is the ability to transmit music, with the full bandwidth, at a ‘CD-like’ 16-bit/44.1kHz. It’s ‘CD-like’ and not ‘CD-quality’ because aptX uses compression, which helps to reduce audio coding delays and minimise latency issues. Classic aptX has a compression ratio of 4:1 and a data rate of 352kbps.
More after the break
What is aptX HD?
Now for aptX HD. This is essentially an updated, beefed-up aptX with the ability to transfer music in better sound quality.
It was released in reaction to the increasing popularity of hi-res audio, and supports audio at 24-bit/48kHz. Compression remains at a ratio of 4:1, with a bit rate of 576kbps.
Whether it is a match for a wired hi-res signal remains to be heard, but Qualcomm seems to be happy gunning for ‘better-than-CD’ sound quality.
What do you need to hear aptX HD?
The CSR8675 Bluetooth audio system on chip
There are requirements for using aptX HD. First you need the right hardware. Specifically we’re talking about the CSR8675 Bluetooth audio SOC (system on chip).
Not only can it handle end-to-end 24-bit audio, it also provides greater digital signal processing than its predecessors. Qualcomm promises a lower signal-to-noise ratio through encoding and decoding, and less distortion too, particularly in in the 10-20kHz range.
The requirement for a specific chipset means that you will get aptX HD only if you have the right devices in the first place: there is no option for a software upgrade later. Nor is there any scope for any sort of audio ‘upscaling’.
The good news, however, is that you don’t need to worry about backwards/future compatibility. AptX HD devices will be compatible with ‘classic’ aptX headphones and speakers.
Which products support aptX HD?
The LG G5 is going big on audio quality, with a modular design that fits an external DAC
AptX HD was announced in January 2016, and will work with Android smartphones, tablets and portable media players.
The first manufacturer on board is LG. The upcoming LG G5 is the first smartphone to handle aptX HD. It can do that with the LG Tone Platinum HBS-1100, the first Bluetooth headset to handle aptX HD.
And... right now there are no other confirmed examples of aptX HD-compatible hardware. Qualcomm doesn’t know (or isn’t saying) what others there may be, as it sees its role more as an enabler of functionality. That being said, the company suggested we may start seeing more products later this year, possibly towards the end of the summer but probably at IFA 2016 in September.
At this point it’s clearly far too early to say if aptX HD is any good. We’ll have to get our hands on some compatible hardware before we can say what advantages this new codec brings. But it’s hard to argue with the idea of better wireless sound and we look forward to giving it a thorough review very soon...