Not specifically about envelopes, but similar for aural awareness.
When I was in collage I had a job at a plastics factory in their lab. Every morning I needed to collect samples from the various production lines - so I had this route I walked that went through a variety of aural landscapes. I started in our lab which basically sounded like an office space. Next was our lab’s prototyping area which was 2 large rooms (maybe 50x100 feet each with 30 foot ceilings) concrete floors and hard walls. This was generally quiet ('cause usually nothing was happening) but my footsteps would echo. Then a quick dash outside to cross an alley into the factory proper. This sound changed a lot depending on time of year and weather. The first factory section was quite noisy, packed with machines rotating molds in tubs of hot water (making acrylic tubes - 10 feet long x 4" to 20" in diameter). You couldn’t be heard here using a normal speaking voice. Next stop a room with about 20 large extrusion machines which squeezed out blocks and rods (1-2 feet across) of nylon & teflon like from a giant toothpaste tube. This room almost sounded quiet compared to the previous, but it had this low pitched electro-mechinical hum that was constant. Last stop was another fairly quiet and normal sized room with acoustics to match.
By having to repeatedly traverse this same sonic path I started paying attention and eventually came to understand how the acoustics worked in these differing environments and more importantly how to hear the “space” of a place. It was like taking a course in ambient acoustics.
At the time, and a direct result of the above, I though it would be cool to write a piece for someplace like a mall (remember those) where the same ‘song’ is playing everywhere but the instruments and arrangement would change depending on the shop - calming in the bookstore, sparkly in the jewelry store, energetic in the shoe store, etc. Then when you walked around the music would be both continuous but customized for the location.
Around this time John Cage came to our school for a lecture & a performance of one of his cut-up I Ching pieces. I think the factory experience opened the door to really hearing Cage’s work.