I've heard that smells are the most effective trigger for old memories, but sounds can work too. It just might take longer for a sound-memory to activate. Last night at 3 AM, one finally kicked in for me.
Living with Sally, I've found that it's best when (not "if") I wake up in the night to pee, to find my way to the bathroom and fumble for the toilet and sit down rather than stand. I don't want to turn on any lights and wake Sally or myself any more than necessary. Also the seat will be down. Also, in the dark, it's just a much safer practice than aiming in the dark. Last night while sitting and peeing, the sound brought me all the way back to my childhood home and hearing my rather modest mother pee. (She never left the door open as my brothers and even my dad were wont to do.) Her sitting made a different sound than what the rest of us intoned and I must have noted it at the time and filed it away for a 3PM retrieval, at least 45 years later. (I left home at 13 for a high school yeshiva-seminary.) If I've peed four times a day and add a bunch for all the nighttime excursions over the past decade, that would come to at least 70,000 urinations before everything synced up for a memory of my long departed Mom. Not the one I would have chosen, given a choice, but the truth is, I like just about any that ever bring her directly into my brain for a moment. At 3 AM in the dark, I smiled and appreciated the sound.