I'll update on my experience with the Backbay Duet 50. IPX 5 and I have been cooling of under the sprinkler fountain at the park with no ill effects
Wind noise is not an issue and bone conduction isn't loud at all and no bother with music or podcasts playing. Aptx and thr right tips will get very solid sound out of them well worth the under $40 price tag. I'll not that they have independent volume control. Not all my BT5/0 stuff does and just turns the player volume. So, I can indeed lower the MP3 player volume down and put the battery strain more on the earbuds. Useful for me when a device states 6 hours of BT and That isn't even combining FM reception and then BT broadcasting which I do at times.
I like the fit. They can lean out a bit at the top with bigger tips, that I recc. for the better sound but then I can do the thumb forefinger pinch to press the button and not do the push the buds in thing. Much better this way! I get the double beep signal when top volume is reached and the other beep to tell you to let go when you FF or RW. They have behaved without issue as well.
Only real issue is that bigger tips are better but they don't fit in the case easily. A little push is needed and you can just drop them in with the magnetic force. Softer large tips like Sony hybrids will turn inside out upon removal from the case which is an annoyance.
Solid for there price and are keepers for me. If they did upgrade to an $99 model with their EQ built in, even better sound, and over double digit battery life I would be interested after my experience with the Duet 50. For now the Duet 50 will certainly be fine to hold me over till some such better models come forth with more features. Provided the Duet 50 hold up which we'll see since you can long term test after a week.
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On another note what about modified SBC(mSBC0 and SBC XQ???
"Bluetooth SBC Dual Channel HD audio mode (SBC XQ)
LineageOS 15.1 and 16.0 bring a unique audio quality enhancement to the stock Bluetooth SBC audio codec. It introduces support for SBC Dual Channel mode with the eXtreme quality profile (SBC XQ), bumping this old codec’s audio quality to levels on par with Qualcomm’s proprietary codec - aptX HD.
An additional “HD Audio: SBC” checkbox is available in users’ Bluetooth audio device settings, as long as they are running a LineageOS 15.1 build created on or after the 31st of March 2019, or a 16.0 build created on or after the 13th of May 2019. Enabling this setting will toggle the Dual Channel mode, which offers an improved bitrate much higher than the one available in the stock SBC codec. The new bitrate of 452 or 551 kbps depends on the Bluetooth device’s maximum Enhanced Data Rate and is a clear upgrade from the stock 328 kbps when using Joint Stereo mode.
The feature is available on all devices with LineageOS support, and can be used by the overwhelming majority of existing Bluetooth playback devices. It works best with cheaper audio devices that do not support additional codecs - aptX, aptX HD, AAC or LDAC."
Would seem to pretty cool to take advantage of SBC since we all know it is capable of higher bitrate and would seem to make sense like it says above for cheaper devices which don't pay for the rights to aptX and such. Just don't know how much we will see this. i did see a couple of headphones just being released listing support for both SBC and mSBC.