By the time you piece together cheap BT buds with the correct compression algorithm, (which I could NOT imagine wearing on an 8 hour hunt...), matching latency transmitter, adapters....You still have cheap earbuds and a transmitter battery that won't last a whole hunt for not much less. How long will those cheap transmitters last? My last one made it almost a year out in the dust and heat.
For the price, quality and run-times I found that the BT set-ups I had (yes, aptX low latencty as well), weren't worth the trouble over just getting the Garrett system.
Keep in mind I DESPISE cheap headphones of any kind be they for music or detecting. It doesn't really make sense to spend $1000 or more on a top notch machine then use generic terrible sounding store brand phones/buds, then have to charge them in the middle of the day or carry a battery pack around with you when you can use something comfortable that gives you a nice clean sound intended and tuned for the frequencies our machines output and get several days of hunting out of a charge.
I'm thoroughly convinced that guys walking around with one ear bud hanging around their neck are missing targets. Some of those little deepies just aren't coming through unless you're paying close attention, have no outside noise and a set of cans that can express those tiny differences in sound.
Spend the $120 or whatever on the Garrett Z-Lynk, plug in your Treasure-pros or Sunrays and be done with it.
Hope everyone hears those deep squeakers and HH!