Bluetooth audio - categorically sucks?

MikeyFresh

Moderator
Staff member
Last weekend I finally got around to spending a bit of quality time with the FiiO BTA30 in Bluetooth receiver mode. I tested it's digital outputs feeding a Topping E30's SPDIF inputs, both coaxial and optical.

On the previously well discussed topic of coax vs. optical SPDIF here at HFH, I had noted the sometimes but not always propensity for optical to be the equal of coax, or perhaps even bettering it, if the inherent galvanic isolation afforded by the optical connection eliminates a source of ground loop. This was not one of those instances, either the BTA30 has a better coax than optical output, or the Topping E30 has a better coax than optical input, or both, but I clearly preferred the coax as more lively sounding, bigger and more dynamic with no penalty in the area of tonal balance. The optical connection though not bad sounding, was a bit subdued and a little blah by comparison.

So coax it was for the BTA30's connection to the DAC. Moving to the Bluetooth source configuration, I wanted to try the Sony "hi-res" LDAC Bluetooth codec, as well as aptX HD. The E30 has a large easy to read front panel display of sample rate, which aids in understanding and confirming you have correctly configured the source to output what you intended.

With some Android phones and tablets you can force the use of the higher resolution Bluetooth codecs by visiting the Developer Options in the device's Settings. This is an otherwise hidden option, most people don't even know it's there. The Android device makers don't really want you using these hi-res Bluetooth codecs, because they whack the battery really hard, so the standard SBC setting is the default.

On the Samsung Tab A 8" Android tablet, I entered the Developer Options menu and found the settings needed:

Developer options default.jpg

I selected LDAC, and noted this particular device only offers standard lossy aptX, but not the 24/48 capable aptX HD codec. You have the option of a fixed sample rate and bit depth, so I chose 24-bit/96kHz for testing with Qobuz hi-res tracks:

LDAC.jpg

Bit Depth.jpg

Sample rate.jpg

Lastly you have the option of optimizing the Bluetooth connection for audio quality, connection quality, or a combination of the two, which yields different bit rates. Because I would be just a few feet away from the BTA30 receiver, I chose to prioritize audio quality:

LDAC Optimized audio.jpg

So all set to go, now to dial up some Qobuz tracks. I wondered if intentionally exceeding the 96kHz sample rate limit would result in the track not playing, so I tried it. No problem, apparently when playing a 24/192 track, half the samples are simply discarded to yield 24/96, the 192kHz tracks played and there were no glitches or transmission issues:

Dreams_Qobuz.jpg

The BTA30's LED indicator was glowing white, which indicates the LDAC codec in use, and the Topping E30's sample rate displayed as 96kHz. The sound was excellent, certainly not the type of compromise I've grown to expect from nearly all things Bluetooth, this "hi-res" LDAC codec is ready for prime time.

I put hi-res in quotes above because it should be noted that this LDAC codec is still lossy at certain frequencies, not unlike MQA, or even MP3, in that it uses perceptual coding to discard some high frequency content that is thought to be essentially inaudible in the simultaneous presence of other frequencies that would mask them.

Now I'll have to check if any of my other source devices are compatible with the competing 24/48 compatible Qualcomm codec called aptX HD which I'd like to compare, for some reason Samsung chose to omit that one from their Android offering on the 8" Tab A. I'd also like to try the BTA30's analog outputs to see if they're any good, but thats for another day.
 

MikeyFresh

Moderator
Staff member
APTX-HD-LOGO-QUALCOMM.png

It turns out that unlike the slightly older Samsung Tab A tablet, my Moto Tab M8 tablet with Bluetooth 5.0 does have the aptX HD codec in it's Android developer options menu:

Bluetooth aptX HD.jpeg

The odd thing is there is still a choice of sample rate all the way up to 96kHz, even though this "perpetually lossless" Bluetooth codec is said to top out at 48kHz. So I guess the device itself can also upsample based on what election you make, I chose the 48kHz spec limit and no upsampling for a brief subjective comparison with the previously mentioned LDAC codec using Qobuz tracks as a source.

BluetoothMotoTabM8.jpeg

As with the LDAC setting, intentionally choosing Qobuz tracks whose native sample rate is greater than the AptX HD spec limit doesn't prevent playback, the tracks will still play and still sound good downsampled to 48kHz.

In my relatively brief back and forth I don't really hear a difference between aptX HD at 48kHz and LDAC at 96 kHz. I wanted to say there might have been a slight preference for LDAC, and that it seemed perhaps a little more lively and dynamic, but that might have been all in my head too, the two were beyond similar sounding.

The FiiO BTA30 did change its LED indicator to glow yellow when receiving aptX HD, and then seamlessly back to white again when switching back to LDAC.

If you have a device that is incompatible with LDAC but does offer aptX HD, I'd say give it a go as "perceptually lossless" at 48kHz using aptX HD also significantly betters standard Bluetooth SBC, just like LDAC does, another example of Bluetooth not always sucking.

The FiiO BTA30 is a very versatile little unit and performs well, better than one might expect at $89, and despite a plastic chassis with no apparent vent holes of any kind, it runs barely warm to the touch when receiving hi-res Bluetooth streams.

The BTA30 runs mature firmware, no weird glitchy behavior at all, at least not in receiver mode, but I haven't tried it yet in its transmitter mode. No freeze ups have happened, and no reboots have been necessary while in use as a Bluetooth receiver. The BTA30 does have a power button and I do turn it off when not in use, upon powering up again it's ready to roll in a split second or so, and pairs very quickly with any previously paired device, faster than any other Bluetooth device I've ever seen, both my phone and 2 different tablets will pair with it almost instantly.
 
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