OF listening options

[London1]

I have decided to use headphones/earbuds during my OF run because I want maximum effectiveness. 

It may also be the only option because we have a soon to be one year old baby and I believe speakers wont be good for him and sleeping in another room really isnt an option.

What is the best format for use with earbuds/headphones? Is masked the only option or can US/Hybrid be used?
What about volume? Ill be using an android which goes up to 15.

[Shannon]

I have decided to use headphones/earbuds during my OF run because I want maximum effectiveness. 

It may also be the only option because we have a soon to be one year old baby and I believe speakers wont be good for him and sleeping in another room really isnt an option.

What is the best format for use with earbuds/headphones? Is masked the only option or can US/Hybrid be used?
What about volume? Ill be using an android which goes up to 15.

Wise not to expose your infant.

You can use masked or hybrid with headphones.  I suggest you set the volume using masked with headphones to a comfortable level, and then see what you think of the hybrid at that level.  If the hybrid ultrasonic bothers you, lower the volume until it doesn't.