I want to record some of my public speaking using a lapel mic while walking away from my android smartphone. I've done this using a standard bluetooth headset. However, the audio is pretty poor. So, I'd like to purchase a better quality microphone (probably a mic that attaches to my shirt). The reviews on amazon for bluetooth mics are pretty bad. The best reviews for this type of mic are mics that have 3.5mm output. I'm wondering if there is a way to convert that into a bluetooth signal that is sent to my phone for recording. I've seen that bluetooth adapters exist, but those seem to be all about hooking up to bluetooth headphones. I've been googling trying to figure out how bluetooth works (receivers, transmitters, etc), but I can't find out if this will work... and I can't seem to find if anyone else is doing it successfully. Any help is much appreciated.
2Broadcasting audio FROM the phone can be done with either the "A2DP" bluetooth profile (which has good quality, used for music and such) or the phone call profile (which sounds, at best, like a phone call). To RECEIVE audio with the phone, I believe you can only use the phone call profile, meaning poor quality. If you MUST be away from your phone, perhaps you could use a wireless microphone that uses a 3.5mm jack or similar. Or, just keep you phone in your pocket and plug in a 3.5mm microphone, clipped to your shirt (I recommend this option if possible.)– BortJan 16, 2016 at 18:31
OK, so I have an ANSWER. I know for sure that the Pryme BTH-300 can accept a microphone plugged in via 3.5mm and sent the external mic's audio to a device via bluetooth (I have one myself). The only bummer of the Pryme BTH-300 is that the audio output, if you're listening to music, for example, is poor.
I'm going to try Sony RM-X7BT which has a microphone input as well as an output that it can send via bluetooth to your phone. I'll try to post on here my findings, but on Amazon for sure.
I believe a number of the products from JK Audio may be helpful with this specific use case. Specifically, their BlueDriver-F3 which is a female XLR-adapted device that can plug into a mic and send the mic signal to a phone (or speaker) via Bluetooth. There are other "Bluetooth Wireless Audio Interfaces" (useful search term) that may work as well.
There are plenty of converters to go from a 3.5 mm output to an XLR male output so that you could use the BlueDriver-F3 with a lav mic with a 3.5 mm output. For example, the Rode VXLR Adapter.