Can I run high-quality aptX headphones on a Silicon Mac?

Had a chance to listen on a Silicon Mac today and it sounded about the same as on Monterey on my MB Air. Looks like Apple may only be supporting AAC now, which suggests no interest in providing the best reproduction via Bluetooth. If so, VERY disappointing and for me, the first black mark in 25+ years.

Also unfortunately I haven't been able to restore OS Catalina to the MBAir in Recovery Mode due to an error message that TM can't connect to my TM backup via wi-fi - although I have no problem accessing TM backups otherwise. I talked with Apple Tech on this as well and they didn't have a workable solution other than trying to do an internet restore to the original OS for the machine (Yosemite?) and then laboriously going though every OS since to get to Catalina. I may be able to restore by connecting to the backup drive directly, but that is yet to be seen.

I think that in the interim I need to go back to OS Catalina via a TM backup, check the audio quality and if it is as expected, use the appropriate commands in Terminal to see what codec it is running. If aptX, I can be pretty sure that's the problem. Then find a Silicon Mac and have a listen :)

Well, not (yet) having a Silicon Mac, I can't check that. But if YOU have, please go into the Audio-Midi Setup and see whether there is any setting to select the codec. This is why I need input from someone with a Silicon Mac who has actually "BTDT."

This is admittedly a rather arcane question, but "the truth is out there"... somewhere. Even Apple seems to be somewhat indecisive. Until I can find someone with a silicon Mac I can try this on myself, I guess I could write an actual paper letter and send it via USPS to Cupertino. I do find it hard to believe that a premium product llike a top-end Mac would compromise audio quality, but if the codec is the culprit, it would seem thatthat's what they did a few OS's ago. I may have to reinstall Catalina on my MBA and see whether the result is what I remember. If it is, it is almost certain that the codec is the problem.

aptX is very much current and is used in some "audiophile" players, like the Fiio, which I also have, and they sound excellent on it. (Not so on my iPhone but I rarely use it for listening.) And the Grados use aptX. As I already stated, I have been in touch with Grado and they are interested in the anwer to this as well.

From other discussions (here I believe) there used to be a tool called Bluetooth Explorer which allowed Mac users to enable aptX but that has been discontinued.

I should add that I am far from a "golden-eared audiophile", although I do have very good audio gear (Bryston electronics and B&W 805/804 speakers.) And I have some hearing loss now but even so the change in quality was definitely noticeable, even on radio streams like my go-to classical station, WQXR New York, which I think are 256k, and on any 320k mp3 rips I've made.

Thanks for that - another option to look into. I was able to download Catalina from the Apple Store (even though the Apple tech said it was no longer available) but it won't install from a machine running Monterey! However, I am considering an Internet Restore, which I understand may instiall the earliest available OS, which might be Catalina. I may also try connecting my TM backup drive directly to the MBAir rather than via the network. I will either partition my Mac HD for Catalina or make a bootable SD card (as my MBA still has a SD expansion slot). So I do hopefully have some options.

Interestingly, my gf, whio has the same Grado cans did an audio comparison test on her 2019 iMac, running Sequoia, via BT and then wired, as well as via her Fiio and had different opinions of the audio differences! Of course, everyone's "ears" are different, but until I can restore Catalina - preferable from my backup - I won't know what differences I hear. I can of course run the cans wired, it's just less convenient.

I've been distractd by another project for a bit but will get back to this. "The truth is out there" as someone famously said on a TV show many years ago :)