Now that new 220.127.116.11 patch has released, custom wavebanks have ceased to work -- I have seen people narrow it down to a new variable in xgs file and possibly a new compression (at least for windows). This tool will probably have to be updated
I had a similar problem in 1.4 when I used my own Wavebank. This has now been fixed, but for some reason in 18.104.22.168 custom wavebanks don't seem to work anymore, and the vanilla terraria wavebank has quadrupled in size. Any notes?