Cheap Bluetooth receiver ( HIEbee 5.2 Bluetooth Audio Receiver YET-R30), and a shallow dive into codecs

HIEbee Bluetooth receiver
HIEbee Bluetooth receiver

So I’m embarrassed to admit I’ve never really given Bluetooth codecs much thought. I guess I just figured, reasonably modern devices would have complementary capabilities and would negotiate the best possible stream, and away we go.

Turns out, maybe not so much. I picked up the cheap! ($10) HIEbee 5.2 Bluetooth Audio Receiver (which identifies itself as YET-R30 via Bluetooth), along with a cheap ($8) short 75 Ω coaxial cable for S/PDIF, to patch into the last remaining digital input on the back of my Modius. For the very low price, I thought it might be nice to be able to listen to my iPhone over Bluetooth as a convenience, vs. patching it in through the Apple Lightning to USB3 Camera Adapter (which I’m finding finnicky to get charging, and so try to leave it connected to the surplus iPhone 12 Pro I’ve dedicated to my listening station).

The device comes with a 3.5 mm male to male cable and a cheap feeling optical TOSlink cable, and has bright blue status LEDs. It feels kind of cheap but for $10, who cares? (And who expected more?) It paired easily with my phone and I fired up some tunes ...

And was immediately left “whelmed.” A/B comparison with the same phone playing the same source over USB and the differences were stark. The HIEbee sounds “okay” but not at all great. A little bit of digging - opening Console.app and watching for “codec” - and I confirmed, this receiver is only negotiating the SBC codec:

    default    09:58:35.101603-0700    bluetoothd    A2DP configured at 44.1 KHz. Codec: SBC, Bitpool: 53 (327 kbps). 5 frames * 119 bytes = 595 per RTP (max=656) every 14.51 ms
    default    09:58:35.123012-0700    coreaudiod             ACSBCEncoder.cpp:214   (0x12ab5c300) Output format:  2 ch,  44100 Hz, sbc  (0x00000000) 0 bits/channel, 0 bytes/packet, 0 frames/packet, 0 bytes/frame
    default    09:58:35.124919-0700    coreaudiod             ACSBCEncoder.cpp:464   (0x12ab5c300) @@@@ 'sbc ' encoder configuration: fsHz = 44100, chanMode = 3, allocMethod = 0, numBlocks = 16, numSubbands = 8, mEncodeQuality = 0, mBitRateBps = 0, bitpool = 53, mCodecDelay = 73

What does that mean? 
In brief, SBC is the most basic codec with the lowest bit rate and, therefore, the most basic sound quality. AAC and AptX are both steps up from SBC and are generally mainstream. AAC is the best you can do on Apple phones and tablets ... SBC offers a (slightly) better sampling rate and maximum bit rate than AAC, though it performs worse, especially on Apple devices. This is because AAC uses a superior compression algorithm, and Apple's phones, tablets, and headphones can run this potentially battery-guzzling codec efficiently. As a result, AAC sounds less lossy than SBC.
Low-complexity sub-band codec (SBC)[:] SBC divides the signal into multiple frequency bands and encodes each one independently. Think of SBC as the lowest common denominator among Bluetooth codecs. It’s not the best. It is, however, mandatory among all A2DP-enabled devices, making it virtually universal. Manageable transfer rates (192-320kbps) are delivered at the expense of significant data loss. 
 
... Advanced audio coding (AAC)[:] AAC is the audio standard for lossy digital audio compression. It also happens to be the license-free standard for YouTube, and for Apple devices. By using a psychoacoustic model to compress the audio being sent to your headphones, AAC is one of the more popular methods to get reasonably good audio quality over a heavily compressed stream. iPhone users will certainly benefit from its higher-resolution playback though [...] It has a transfer rate cap of 250kbps, creating a file similar to that of a standard-quality MP3 [...] AAC is a much more complex codec than SBC. As such, it offers much better audio quality than SBC, even though it offers lower bitrates and sampling rates. AAC’s efficient implementation on Apple devices specifically makes it a no-brainer if you are embedded in the Apple ecosystem.
 
 
So, me being me, now that I know there’s a better solution out there, this little $18 project is starting to creep ... The $35 BluDento B1 supports the AAC codec, takes USB power, and has a coaxial S/PDIF output, so, drop-in replacement. The $107 blafili B3 Professional is a full on DAC in its own right and would make the Modius redundant (without the slick stacking and Snakebite interconnect and...), looks cool, but also, having what is essentially a streamer be more expensive than the (albeit 10 year old and cheap!) Mac mini I picked up as a source, seems really silly ... Okay, I’ve talked myself out of the B3, and out of even considering a WiiM... But I am definitely contemplating the B1.


Edit: Except, I want to be able to have a laptop, and a phone, paired at the same time, and pause one so I can play the other, without having to disconnect and reconnect etc. Reading the manuals (B1, B2, BLT-2), it looks like only the BLT-2 ($80 on Amazon, $60 on BluDento’s site) or B2 ($123 Amazon, $100 BluDento) will have that capability. (B1 manual: “Make sure no other devices are connected.
If so, either disconnect or turn off Bluetooth on the other devices.” B2/BLT-2 both have sections titled “How to pair two phones,” with the note: “Only 1 phone can play at a time, you have to pause the other.” Exactly what I’m looking for. Now, is the kinda nifty screen, pairing button, and USB-C power connection, worth a $40 premium?)


Another update: In response to a question on Amazon (on the blafili B3 product page), this answer was posted, with language identical to the BluDento manuals for the BLT-2 and B2; seems the blafili B3 is from the same manufacturer (emphasis added):
Hello from blafili B3 support Here is the guide of HOW TO PAIR TWO PHONES 1. Power on blafili B3 Bluetooth receiver 2. Enable Bluetooth on the 1st phone, search and connect to “blafili B3” 3. After pairing successfully, disable Bluetooth on the 1st phone. blafili B3 will enter pairing mode again. 4. Pair BluDento to the 2nd phone by the same way. 5. After pairing successfully, enable Bluetooth on the 1st phone, click to connect “blafili B3” again. 6. Now both 2 phones are connected to blafili B3. Note: Only 1 phone can play at a time, you have to pause the other.
I’ve also seen the xDuoo XQ-50 Pro 2 recommended as being a higher build quality alternative, but the manual doesn't address using two devices and xDoo generally doesn't fill me with warm fuzzies (appears it may be the same company (or within the same jítuán?) as SMSL and LOXJIE (etc.?) so probably fine but ... IDK.)

... Exploring that topic a bit more; apparently Shenzhen shuangmusanlin electronics Co., Ltd. is the parent company of SMSL, Loxjie, Sabaj, VMV. Shenzhen Cavins Technology CO., Ltd. owns One Little Bear, Nobsound, Douk Audio. Shenzhen xDuoo Technology Co., Ltd. may be stand alone? The website is almost identical to the other companies’ - but maybe they’re just all using the same WordPress guy. 

(As much as I’d love to get the Audioengine B1 and support an American company, for this particular component it’s not worth the > 300% premium to me, right now.)





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