I think that it is clear that Note9 does not support aptX HD or Adaptive. Why? - Million dollar question
Samsung does not release any statement on this and in my option never will.
It is possible the Exynos Bluetooth modem does not have support for it, and thus they want to even it out on both variants. I can't find any info about the Bluetooth modems except that the Snapdragon S9+ has a Murata KM7N16048.
If you addressed your reply to me I did not use external DAC. It doesn't matter where I stream music over Bluetooth, Note9 or Onkyo DAP, internal DACs and amplifiers are not used as signal is transmitted digitally over Bluetooth. Only DAC of my Sony Bluetooth heatphones is used.
Comning back to the topic, I udnerstand your concern about lack of Aptx HD or Adaptive in NOte9 after updated. Unfortunately I can't comment on it as my reply was not about which codec Note9 be using after updated. I replied regarding your ability to choose which codec to use and how to choose it. Based on your screenshot your Note9 chose aptX automatically. And the reason for that was becase B&W supports only 3 codecs, aptx-HD, AAC and SBC and Aptx was the best codec both your Note9 and B&W PX headphones supported.
If your Note9 didn't choose Aptx automatically but stayed at SBC instead you can check if you have an option to enable it in Connectoins - Bluetooth menu when your headphones are connected. Attached is screenshot of my Note9 allowing me to enable LDAC for connected Sony WH1000XM3.
My Note9 doesn't support either Aptx HD or Aptx Adaptive. But it does support LDAC so is my Sony WH1000XM3.
Hence I am lucky as with LDAC I don't need Aptx HD or Adaptive.
However, I am not sure you will be able to tell the difference between Aptx and Aptx HD listening to your B&W.
If you can test your B&W using some other smartphone or DAP supporting Aptx HD, use same music file, same player, no EQ and see if you can tell the difference. If Aptx HD is really what you want then you will either need to change the smartphone or buy DAP or change your headphones for ones supporting LDAC whcih allows higher transfers and bitrates compared to Aptx and Aptx HD.
Hope this helps.
I realise the headphones only support up to a maximum of aptx HD. However, I have been advised by both Samsung and Bowers & Wilkins that aptx Adaptive is backwards compatible with aptx HD but according to the settings I'm getting CD quality. Even the basic aptx codec is capable of CD quality at 48 kHz/16 bits per sample. So by that rationale my screen shots should be showing that rather than what they are actually showing which is 44.1 kHz/16 bits per sample. I can manually change the settings to show 48 kHz/24 bits per sample but exiting Developer Options reverts things back to the original settings. Although Samsung couldn't be bothered to incorporate aptx HD on a flagship handset at release and waited several months to release a supposedly better codec in a software update I should probably count myself lucky that they've at least kept the audio jack so I'll probably just use the audio cable that came with the headphones and benefit from better battery life.
As FYlegend wrote and to my humble opinion it is either an hardware limitation on their exynos or licensing issues on their exynos chips and they can't enable it just for the US market where they use snapdragon chip. - it wouldn't be the right marketing decision.
I should add that I am not in favour on having to use a exynos device. I would prefer to have a snapdragon. It's all about money in the end.
Still, considering how close Samsung is with Qualcomm, it's poor judgement on their part if it's a hardware limitation with Exynos. Licensing is a poor excuse since Huawei has AptX HD on their Kirin devices.
To be honest I've kind of lost interest now. I've had Samsung handsets for years but I'll be changing that when I look for a new one and I certainly won't be making the same mistake of assuming a top of range phone has basic compatibility that cheaper phones do. Might be time to look at Apple or Sony.
Finished updating the Telus Canadian version of the Note 9. APTX HD and APTX Adaptive are NOT available options.
This is disappointing, as the lack of APTX HD was almost a dealbreaker for me. My 3 year old LG G5 supports the codec, being the first flagship phone to support the codec.
This is a Major Fail on behalf of the Samsung team for omitting a very mature and desirable technology for audiophiles. Yes LDAC is available, but that does nothing for customers who have invested in high quality audio hardware which should be supported.
Update: I'm now considering ditching bluetooth altogether and I'm considering buying an Audioquest Dragonfly Red external DAC. It is a nice unit that will allow me to bypass the crappy internal audio on my laptop but I'm not sure whether the Note 9 is able to output audio via the USB-C port. Other forums seem to be suggesting that it's not possible as the phone still has the 3.5mm headphone Jack. In the Default USB Configuration options I can only see settings for Transferring Files, USB Tethering, MIDI, Transferring Images and Charging Phone Only. Does this handset allow routing audio through the USB-C port with an OTG cable or has Samsung omitted yet another basic function that cheaper handsets are able to provide?