I hear interference in my earphones from a heart rate monitors. The connection between the cord and headphones is at exactly the same position as the heart rate monitor, so I can hear the signal it emits over top of the music I'm listening to. Comments?
Earbuds work on an electro-magnetic principle. The heart-rate monitor likely produces an electro-magnetic pulse that radiates outward and is picked up by the earbud cable, acting as an antenna. The pulse is transduced into audible interference by the earbud driver.
It is feasible that any earbud will act the same: some will be worse, others will be better. But as earbuds are electro-magnetic in nature, they will react to an electro-magnetic pulse in an audible manner.
Sorry, we do not have a solution to this interaction between the heart-rate monitor and the earbuds.