I've made some progress in the shed.
A fair bit of cosmetic work to be done, but the "studio" is in working order (more or less).
I had some building material left over, which enabled me to build a wee booth in one corner.
This is a bit of an upgrade from the iso cab in terms of utility & sonic quality.
Unfortunately, it's a step down in terms of actual isolation.
I had enough plaster board to do a double layer on the two segments of the booth that are up against the outside wall. But as I found out, was not quite enough.
When testing with Vocals & Acoustic guitar, the neighbours can't hear my horrid warbling and mistake riddled string plucking. Sound is audible in the main room (mostly via the door), but not outside the shed itself.
The local hardware store didn't have any solid core doors in stock, so I compromised & went with a hollow door, which is covered in various soft materials. It ain't perfect, but it is better than no door at all.
Bu as I said earlier, for the quieter instruments, the isolation is good.
The disappointment came when testing me favourite 15 watt valve amp.
At 2 on the volume dial, it was audible outside, though muffled and not likely to disturb the neighbours too much. And the amp does sound quite nice at this level, but there is a sweet spot between 3 & 4 where the amp is very responsive to dynamics. You can go from nice & clean, to breaking up depending on how hard you strike the strings. If you want more distortion, naturally, you turn up the volume.
On this amp, 5 (it goes to 10) is pretty much peak volume. Anything after there just adds to the amp's gritty overdrive. At peak volume, the amp was definitely audible outside the structure. I asked myself, would this annoy me if it were coming from one of my neighbours? The answer was yes.
I have spent the morning piecing together bits of scrap plaster board to make a 3rd layer on the smaller of the external walls. It turns out that I had almost a full 1200x2400mm sheet worth of scraps in the workshop.
Sure it's messy work, but at least I'm not adding to land fill and I am in fact reducing the amount of wasted material on this build.
When the new plaster is dry and the fittings are in place, I'll do some further testing.
Here's hoping that the 3rd layer will do the trick!