MergeAudioParams.js

// Allows to set a parameter value for multiple nodes (of same kind) at the same time
function mergeParams(params){
    const singleParam = params[0]
    const parameter = {};
    const audioNodeMethods = Object.getOwnPropertyNames(AudioParam.prototype)
    .filter(prop => typeof singleParam[prop] === 'function')
    
    //allows things like parameter.setValueAtTime(x, ctx.currentTime)
    audioNodeMethods.forEach(method => {
        parameter[method] = (...argums) => {
            const args = Array.prototype.slice.call(argums);
            params.forEach((param) => {
                singleParam[method].apply(param, args);
            })
            
        }
    })

    //allows to do parameter.value = x
    Object.defineProperties(parameter, {
        value: {
          get: function () {
            return singleParam.value
          },
          set: function (value) {
            params.forEach(param => {
                param.value = value
            })
          }
        }
      })

    return parameter;
}