I have some active speakers which don't have volume controls on them and I don't know how to control the volume on them. The only way I have been able to do it is when plugged directly into my phone via adaptor. The speakers input via RCA connections and I don't have any way to control the volume when connecting to say a turntable. I looked online at volume controls but can't find anything suitable which allows audio input via RCA and outputs to RCA. Also I don't know if this would even work, any one have a solution??