[immerlustig]

in a head down position pressure on your chest is lower than pressure on your ears, so a valsalve eq, for example, would require a lot greater effort. a frenzel eq produces a lot more pressure, uses less muscles and is therefore a lot easier and quicker to perform.

if you do deep dives and have to switch to mouthfill eq, then bringing up air into your cheeks requires a great effort again (diaphragm and chest muscles)because of the pressure difference. doing that head up would be a lot easier because the pressure difference would be favorable.

problems with unequal eq could also result from uneven tubes or mucus production.

cheers,

roland