we are designing a fairly compact PCB for a communications device. We are looking at using BLE as a link for voice to a separate microphone, and BT Classic to be paired with a smartphone. We are using pre-certified modules, and they will located on the PCB about 20mm away from each other (can extend this to 40mm if need be). Is there a risk of interference between the 2? We are transmitting audio in both cases so interference would be particularly noticeably. They both operate at 2.4GHz, but I understand they have different frequency hopping techniques, and hoping this will allow for coexistence.
They are both 2.4GHz, but BLE uses an adaptive frequency (channel) hopping algorithm to avoid congested parts of the the spectrum, so at least BLE should tolerate Classic. Not sure about the other way around. Presumably it should be fine because BLE will avoid Classic to the benefit of both.
As for audio, it's all digitized by the time you are in Bluetooth, so you won't get degradation in quality, but maybe dropouts.