I recently found that if I connect a USB pair of speaker/microphone using OTG cable to a phone, it becomes the audio device by default, and I can actually play audio over that. It happens that the USB headset has much better quality than the earplug ones that I connect over audio connector.
My question is, if I use this OTG-USB-Headset trick, will it drains the battery faster than just having my earplugs connected on the audio connector?
What you have tried now is known for long as you can see from Google search - connecting usb headset to usb on the go
.... will I drain my battery faster than just having my earplugs connected on the audio connector ?
Depends on the power rating of your USB headset- if it is more than the earplugs provided by the phone (common case), then yes it will drain faster
Additional Information
See avs forum for more insight for audio use case
Maxim integrated application notes for electrical details
Q & A