Fishhooks, you inspired me to do a quick check of the three Blu-ray/DVD versions of The Sound of Music I have. I had thought there was no foley sound of "The Apron Slap" on my earlier versions, but it turns there is evidence of it in some cases but I was probably comparing it to the sound you hear in the theatrical presentations I've seen since and, by that comparison, those are still very subdued.
Again, I don't think this is an insignificant issue. I think the Loud & Clear awareness of that slap and no doubt dozens of other examples of now nil or subdued foley sound effects elsewhere is what helped give this movie a greater sense of being "alive and present" that, unfortunately, is too often lacking in the blu-ray and dvd versions.
I didn't go far beyond "The Apron Slap" and "The Footsteps on the stones across the brook" in the opening scene because it would just take too much time and effort to go back and forth between different discs. But for the fun of it and for your and others' comparisons, this is what I found. Others might hear something different, of course.
Like you, I'm going with "nil" to characterize what might be found under certain circumstances where the listener is really searching for it, but is so subdued as to be ineffectual, imo. The other characterizations, Loud & Clear, Audible and Barely Audible are, of course, my subjective impression as well.
"The Apron Slap"…and "The Footsteps on the stones across the brook"
U.S. Blu-ray, Combo Pack:
Eng. 7.1….nil…and nil. (this is the most unfortunate finding in the group, of course)
French 5.1 DTS….Loud & Clear…and Barely Audible.
Portuguese 5.1….nil…and nil.
Eng. 4.0 Dolby Surround….nil…and nil.
Spanish 5.1 Dolby Digital….Loud and Clear…and Audible.
Eng. 5.1 Dolby Digital….Audible…and Audible.
Eng. 4.0 Dolby Digital….Audible…and Audible.
Spanish Dolby Surround….Loud & Clear…and nil.
French Dolby Surround….Loud & Clear…and nil.
40th Anniversary Edition DVD (2005):
Eng. 5.0 Surround….nil…and Loud & Clear.
Eng. Stereo….nil…and Loud & Clear.
French Surround….Loud & Clear…and nil.
Spanish Mono….Loud & Clear…and Barely Audible.
2-Disc Set Double Digipak Collector’s Edition (2003):
Eng. 4.1 Surround….Loud & Clear…and Loud & Clear.
Eng. Dolby Surround….Loud & Clear…and Loud & Clear.
French Dolby Surround….Loud & Clear…and Loud & Clear.
Robert Wise Commentary on the Blu-ray and 40th Anniversary Edition (2005):
Loud & Clear…and Loud & Clear on both versions.
Robert Wise Commentary on the 2-Disc Set Double Digipak Collector’s Edition (2003):
nil…and nil. (odd, since this DVD version is the only one where you hear those foley sounds Loud & Clear on all other sound options)
Btw, the 2-Disc Set Double Digipak Collector’s Edition (2003) is the only version that correctly clarifies by mentioning it in the menu options that the Robert Wise Commentary is ALSO an “Isolated Music Score” bonus feature. Neither the 40th Anniversary Edition DVD nor the 2010 Blu-ray mentions that it also includes an isolated music score feature and that might cause some confusion as to why there are no voices on those versions during several stretches where Robert Wise offers no comment.
And, if you REALLY want to hear how loud "The Apron Slap" and "The Footsteps on the stones across the brook" foley sound effects can be and should have been on these home theater version, imo, listen to the Robert Wise Commentary track on this Blu-ray or 40th Anniversary Edition DVD!