DMSI 3.3.2, OED, X124, PSEv3, etc.

[Shannon]

Playing the subliminal at a lower volume will still be audible to the subconscious, even with other sounds present.  I have done experiments which prove that even a volume of 1 click on my cell phone can influence testers as far as 15 feet away, when they could not consciously hear normal audio at that volume and even half that distance.

The effect of lowering the volume is to present a gentler "request" to the subconscious, and go deeper into it.  It frequently works better than higher volumes for specific personality types.  By your description, I would say that it was DMSI.

Shannon, do you think this very low volume thing is true of all your subs, of all silent subs? I have tended to play at the loudest volume that doesn't cause pops and crackles. Maybe varying it up would be effective. Currently, I've been listening in the background most of the day, then for a couple hours in the afternoon listening to the hybrid on the earphones (ocean version, the stream makes me want to go to the bathroom... which reminds me, the first subs I tried had a 'rain' option, which was always my favorite, ocean was my second.)

It is true of all audio subliminals.  That is why you get different results from masked, ultrasonic and hybrid formats.  Playing it just below pops and crackles is too loud for some people.  Volume = aggression to some personality types.  So does hybrid vs one of the non-hybrid formats.  Just as with a woman sexually, gentle can go a long way.