[Spektykles]

Bad range are due to bad signal layout design/antenna, since all the QCC chips have limited power output. Some of the better design have huge gain antenna or fancy one like ceramic or laser etched one.

 

[Blacklands]

4. Aptx Adaptive gets quite low bitrates compared to from my sony phone. This appears to be range sensitive. only getting >400kbps within a few cm range.

I see the same behavior with the Sennheiser BTD 600 (and the Qudelix). Seems the antennas in these transmitters just can't do more, for whatever reason (size, quality, power delivery, processing, I don't know).
Adaptive also generally has lower bitrate than most of the other codecs, though; that doesn't mean the quality can't still be good. There's limits, of course. But bitrate alone is just one of a bunch of factors.
I'd love to see a transmitter with much better range, though. I guess we probably won't get that at such a small form factor, or it might be significantly more expensive. I actually wonder if a transmitter that's natively USB-C and actually uses USB Power Delivery and actually requests more input power could send a stronger signal, with all other things staying the same. Or if the antenna itself is just too small or too bad.

 

[master grunthos]

I see the same behavior with the Sennheiser BTD 600 (and the Qudelix). Seems the antennas in these transmitters just can't do more, for whatever reason (size, quality, power delivery, processing, I don't know).
Adaptive also generally has lower bitrate than most of the other codecs, though; that doesn't mean the quality can't still be good. There's limits, of course. But bitrate alone is just one of a bunch of factors.
I'd love to see a transmitter with much better range, though. I guess we probably won't get that at such a small form factor, or it might be significantly more expensive.

A bit more testing reveals it manages aptx HD across the whole house through several walls with no drop outs or issues. The Qudelix reports the constant 500+ kbps as you'd expect for HD. It's possible that other artefacts in the signal are being introduced while in HD but the throttling of the Adaptive bit rate seems to be more than just a matter of range.

Perhaps it's trying to keep latency low or use low power whereas the HD codec may just be a fixed output. Only Qualcomm will know for sure. For me, HD will do the job so it "works".

 

[Blacklands]

I also dislike a lot how these devices don't give you more control over Adaptive. Hell, even for LDAC with its 3 fixed bitrate settings you can say that you want to prefer high quality, even if it makes the connection drop. I know Adaptive is suppose to "figure it out" by itself, but I'd like to be able to just tell it what I want. If I want low latency all the time, let me set that. If I want maximum quality even if it means dropouts, let me have that.

 

[O11111]

I also dislike a lot how these devices don't give you more control over Adaptive. Hell, even for LDAC with its 3 fixed bitrate settings you can say that you want to prefer high quality, even if it makes the connection drop.

That's actually (kind of) supported, but probably dongle manufacturer simply didn't make use of that feature. There are 2 quality modes: low latency and high quality (with 96 kHz). But Adaptive is such a mess. AFAIK QCC5124 used in Qudelix 5k only has aptX Adaptive r1.0 which lacks certain features. But it will probably still decrease the bitrate to circumvent dropouts even in HQ mode.

 

[Blacklands]

I'm glad we can at least see the current Adaptive bitrate on the Qudelix 5k now. When I got mine that wasn't available yet.
Being able to switch between the two modes would be nice already. It seems it's just about software support, then. Sadly you actually get screwed over if you buy a "reputable" transmitter like the Sennheiser one, because it doesn't have any software. Unlike the AliExpress ones, which do have software to control various features, from what I saw in this thread? Makes me regret not buying one of those, I guess. Would have been cheaper, too...
Actually, now I'm wondering if there is any software that just addresses the Qualcomm chip inside directly...? Which then might work for any dongle using it?

 

[O11111]

Actually, now I'm wondering if there is any software that just addresses the Qualcomm chip inside directly...?

There exists generic SDK for these chips, so it obviously can support that.

Which then might work for any dongle using it?

Probably no. While there is something close to that (pydbg), I'm almost confident that it won't work for all of them.

 

[myn]

This thread is epic but having a hard time determining what the latest greatest bang for the buck is is. Can anyone please recommend the best options with links as of now? And perhaps we can edit first post to make it easier for new comers?

 

[thugnificent]

Anybody heard or tried this transmitter? Seems to have newest aptX adaptive lossless.

https://www.aptx.com/products/nura-bluetooth-5-3-audio-transmitter
https://www.nurasound.com/products/bluetooth-audio-transmitter

 

[xSDMx]

Anybody heard or tried this transmitter? Seems to have newest aptX adaptive lossless.

https://www.aptx.com/products/nura-bluetooth-5-3-audio-transmitter
https://www.nurasound.com/products/bluetooth-audio-transmitter

Tons of discussion about it in this thread. Use search.

 

[O11111]

Seems to have newest aptX adaptive lossless.

Probably not. Would be highly surprised if so.

https://www.nurasound.com/products/bluetooth-audio-transmitter

Unfortunately, they don't mention the chip used, so the following is only a speculation. If it's the same QCC3056/3040 used in other dongles then it has no advantages compared to them (except, maybe, better control software). But if it has recent QCC3086 then in addition to all of that it will have LE Audio (LC3, aptX Adaptive/Lite) and that's it. Most likely they didn't go for QCC5 (and 60$ for QCC3 is a robbery tbh), so this will only have SBC, aptX and aptX Adaptive (not even HD or LL. Not that LL is useful and well-supported, but still).
One might be more interested in DIY solution. BTM386 on AliExpress is only 11$ (not including shipping) and BTM581 is 17$. Latter could get LDAC, LHDC and others. Custom PCB are not expensive now, about 5$. And if one would find proper aptX Lossless libraries for that chip (without Qualcomm being nice on that the reverse engineering Hexagon DSP ones from some Snapdragon device would be the only option).

 

[Mightygrey]

I use the Sennheiser BTT100 for Aptx LL gaming with my Grado GW100x. It's lag-free and has worked faultlessly thus far.

 

[asheny]

With the KB9P (and possibly other models), does anyone know what the 'PS5 high volume mode' actually does? The description just says 'double volume' but the instructions make mention of the microphone.

 

[C_Lindbergh]

Any1 got the Bluetooth assitant for the KB8P? Links in previous post seems to have expired.

Also, is it worth to update from KB8P to KP9P?

 

[seeteeyou]

Sony Xperia 1 IV and Xperia 5 IV finally got updated to Android 13 while they're enabling support for aptX Lossless officially, so far it's available in China and Japan

https://service.sony.com.cn/download/firm/00003002.html
https://service.sony.com.cn/download/firm/00003022.html
https://www.au.com/information/notice_mobile/update/update-202301-sog06/
https://www.au.com/information/notice_mobile/update/update-202301-sog09/