John Darko
Our recent video coverage of the Sony Xperia 1 V smartphone revealed its 3.5mm headphone output to be serviceable but nothing more. However, a headphone socket wasn’t the only reason I put down cash on the Sony. Its internals come kitted out with Qualcomm’s Snapdragon Sound chipset to support aptX Lossless. Paired with a similarly equipped receiver, lossless CD-quality streaming over a Bluetooth audio connection comes strolling into view. The Sony smartphone had laid the foundation for aptX Lossless. What I needed now was an aptX Lossless-capable receiver…
…and at time of writing, there aren’t many of those. The Denon Perl Pro and Bose QC Ultra Earbuds are two. I’ve already purchased both. Initial testing reveals that both the Denon and the Bose show an aptX Adaptive connection when paired with the Xperia 1 V.
‘Adaptive’? Presumably, because the codec must adapt to its environment: the connection drops to a lossy level in spaces already bunged up with Bluetooth streams (like transport hubs) or when, for whatever reason, the Bluetooth connection weakens. However, in less congested environments and/or when a robust Bluetooth connection presents, Qualcomm promises lossless transmission of 16bit/44.1kHz audio.
You can read more on aptX Lossless’s 2021 announcement here.
What about aptX Lossless with wired headphones? For that, I’d need a Bluetooth-equipped source that also loads in an aptX Lossless-capable chipset. One such unit is the iDSD Diablo 2 from iFi Audio: a battery-powered hi-res DAC and 5 Watt (see update below) balanced (see update below) dual mono-circuited headphone amplifier with analogue, USB and coaxial/TOSLINK combo sockets for wired hook-ups, balanced and single-ended outputs and a Bluetooth input that talks aptX Lossless. Hello, ladies.
Would iFi send me a sample for a long-term dig into (what many consider to be) the last remaining obstacle for broader wireless headphone adoption by the audiophile community?
Yes, they would.
I unboxed the iDSD Diablo 2 the night before jumping on an early flight to Lisbon. Inside the box, we get a nice padded carry case with elastic straps to house the supplied and numerous cable interlinks. During the unboxing process, I took a few photos but there was no time to read the manual or consult with the quick start guide. I would power the unit on for the first time during a 4:15am airport coffee and, quite literally, play it by ear.
It was then that the first wrinkle arrived. Why did the lady who lives inside the iFi brick say “LDAC” soon after the Sony smartphone pairing? Why did the phone’s Bluetooth settings panel read the same: LDAC?
I already know that LDAC streams can sound superb. That was underscored by 4 hours of in-flight listening to Thomas Dolby, Alva Noto, The House of Love, New Fads and Peter Gabriel through the Diablo 2 and Sennheiser IE900. But as terrific as this LDAC connection sounded, especially with the Diablo 2’s amplifier section fattening up the previously ectomorphic Thomas Dolby 12×12 Original Remixes release, those streams are still lossy.
An email exchange with iFi in the UK ensued. They told me that I should install ‘the Gaia’ app to disable all codecs except aptX Adaptive. Another wrinkle: the Gaia app can’t be found on the Google Play store. It must be side-loaded via an .apk file directly downloaded from iFi’s website. And true to iFi’s word, disabling all but aptX Adaptive effectively forces the Sony/iFi to use aptX Adaptive for Bluetooth audio. In the Xperia 1 V’s Bluetooth settings panel, it now reads aptX Adaptive where it previously read LDAC.
Back with the iDSD Diablo 2, the LED next to its volume wheel changes colour depending on the codec (or level) in play. From iFi’s online manual (with my emphasis):
- Off SBC
- Yellow AAC
- Blue aptX
- Magenta aptX HD
- Green aptX Adaptive
- White aptX Lossless
- Red HWA/LHDC
- Cyan LDAC
Over another morning coffee, this time at a more sensible hour, I am seeing only aptX Adaptive green (courtesy of the Gaia app) but there’s no sign of aptX Lossless white. So far, so Plexamp. A switch up to Roon ARC as the playback app changes nothing and its Signal Path tells us that the Sony phone is upsampling CD-quality audio to 48kHz before Bluetooth dispatch.
Qualcomm could certainly do more to explain to consumers that aptX Lossless is the uppermost tier of aptX Adaptive. Google isn’t helping either. Android shows the codec but not the (lossless) level. Bitrate display? Fuggedaboudit. I hate to say it but I will: the pursuit of a lossless Bluetooth connection’s visual confirmation so far has all the hallmarks of MQA. What colour is the LED? Is the audible improvement obvious? I’m not saying that iFi’s IDSD Diablo 2 can’t handle aptX Lossless, I’m saying we don’t yet know when it’s in play.
There is some deep-rooted psychology at play here: many buying this kind of hardware to facilitate a lossless Bluetooth audio connection will likely want to see a lossless connection before they hear it. (If they can hear it at all). Don’t hate the player, hate the game: we eat with our eyes first, even in audio.
Another email has been dispatched to iFi to render this iDSD Diablo 2 preview post incomplete. Until I hear back, it remains to be continued…
Further information: iFi Audio
UPDATE 8th January 2024: Headphones.com’s review video of the iFi iDSD Diablo 2 shows that the maximum power output of 5 Watts specified by iFi is peak power (and not RMS continuous power) and that iFi’s peak power measurement uses a much shorter time window than the industry standard. The RMS continuous output of the Diablo 2 was measured by Cameron GoldenSound to be 1.6 Watts from the balanced output and 2.3 Watts from the single-ended socket. iFi has since updated its online spec sheet:
Those numbers are with the Diablo 2 plugged into the wall. According to Cameron, we can expect to enjoy around half the specified output power once the Diablo 2 is running from its internal battery. Why does the Diablo 2’s single-ended output have the power advantage? Because, according to Headphones.com, this amplifier is not a true-balanced circuit design.
