shroud options for a quiet Mutant Short?

Bizill, I’ve researched about drilling holes in shrouds, mainly on this site, but around-the-web searches too. Right now I’ve drilled only two holes in my Short’s ldc. On the advice of members who’ve gone (there) before me, I drilled the holes as close to the barrel muzzle as I felt comfortable with: about 0.30″ or maybe a bit less. These two holes were placed to dissipate as much of the back-blast from the nearest baffle. Long story-short: I had reduced the power to 17 fpe before trying to evaluate the effect of these two vent holes. It’s got me thinking about rearranging the spacers in the ldc.
Currently the larger, (holed) is inserted first, followed by a baffle. My thinking was to use the larger volume of that spacer as a means to help lessen the blast (as it expanded into that spacer). Now i’m thinking of using a shorter spacer, then a baffle. Maybe that would yield a better result.
Speaking of the result, not much science to share. To achieve my goal of having a very quiet and compact urban pcp I’d reduce power then try to further reduce the report until I was satisfied I’d gone as far as feasible before taking the next step and buying an ldc (for my ldc 🙂 ). So, reduce power: 17 fpe or less. I’m not sure how much less. I don’t know how the regulator responds to low power, or even if that’s an issue. Low power; less noise. Add vent holes; lessen noise further(?). Again, general consensus seems to be adding vents close to the muzzle and that doing so yielded some positive reduction in noise, to a point. That point might be “variable”, different for each shooter. There can be too many holes as well as (hoping) too few holes). I thought about using an Android db meter; only for relative accuracy. 4-db is 4-db (+/-). But in truth I am going for the subjective (can’t prove it to anyone else but me) route. I want to hear if I can make the report of my Mutant Short fit my expectation?
Can’t judge me ’cause I said “subjective”. 🙂

So my current thinking (while I await some more “me” time) is using the smallest spacer near the muzzle so that the baffle nearest to the muzzle is redirecting as much of the blast in as short a space as possible, not allowing it to expand so much. So where does air density enter in to deciding the number of vent holes, and their size? I haven’t found anything on that. Might not be a thing.

I have two holes one at 12, one at 6. Maybe add holes at 9 and 3? Or add them in tandem at 12 and 6? I don’t know which way to go with this. What works?

Stick with the process: low the power until it feels right , smallest spacer goes in first, record sound with two vent holes. Evaluate result (subjectively). Have enough sense to know when to quit.
Darryl

I have tested a Sumo, and the difference is easily discernable. I should look into how it’s tone can be changed. It quiets the “snap”, but the sound still seems a noticeable pitch higher than I’d like. It’s like I’m needed to quiet an echo of sorts, and a lower tone seems interesting to try. That’s why I also wonder if the “snap” of the shroud (itself) can be altered and lowered? But yes, a Plan-B is peace of mind.
Darryl