> They are all based on same chip. So if you buy 5€ BT-headphones and plug them into 1000€ dumb headphones, they very much sound the same as 1000€ BT-headphones

> They are all based on same chip. So if you buy 5€ BT-headphones and plug them into 1000€ dumb headphones, they very much sound the same as 1000€ BT-headphones. That is not strictly true. While the vast majority of microcontrollers used in BT headphones come from a handful of companies (usually Qualcomm, Realtek or JieLi), the DAC and amplification stage is going to be different. Cheap headphones use the microcontroller's built-in DAC while higher end models can have a discrete chip, or sometimes a custom ASIC that also handles noise cancelling. The protocol itself and the SBC codec are still a bottleneck of course, but in my experience an ESP32 paired to a decent quality I2S DAC module sounds much better than a random cheap BT receiver module (and has no annoying voice prompts).