Antique Car Stereo Bluetooth Audio Retrofit with ESP32 - Part 2
Good Bluetooth Aux Receivers for the car
Can't help you much.
Bluetooth in a nutshell.
It takes 2 to tango so sender and sink must use the same protocol.
Mandatory is SBC, proprietary codecs like APT-X rewuire explicit support by both sender and sink.
To save bandwidth, Bluetooth used lossy compression. SBC can run at 320 kbs so high bit rate MP3 style.
The sink (receiver) receives the compressed audio. It is expanded to PCM audio, fed into a DAC and the output is amplified.
A bit more about Bluetooth: https://www.thewelltemperedcomputer.com/HW/Bluetooth.htm
Measurements are a bit rare so hard to recommend you a product.
Maybe browse ASR, couple of examples
https://www.audiosciencereview.com/forum/index.php?threads/topping-bc3-review-bluetooth-receiver-bt-codecs.23740/
https://www.audiosciencereview.com/forum/index.php?threads/qudelix-5k-bluetooth-dac-headphone-amp.17386/
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