You must have MILITARY RADIO and STEAM CROSSOVER to make AUDIO RACK. You can find this item in music category. Using growspray would be madness, better get a time machine. Nice experience you find in these blocks. AUDIO RACK can be broken. Seed mathematics is very complicated, but you should get at least 1 seed back from splicing AUDIO RACK. Will you strike it rich? You just have to count the gems yourself. Blockratio of AUDIO RACK is a mystery. Maybe you can check the wiki for <a href="https://growtopia.fandom.com/wiki/Audio_Rack">audio rack</a>