public void UnregisterDroneSynth(DroneSynth synth)
 {
     if (_synths.Contains(synth))
     {
         _synths.Remove(synth);
     }
 }
        /// <summary>
        /// Register a DroneSynth to get updates from this DroneMachine
        /// </summary>
        /// <param name="synth">the synth</param>
        public void RegisterDroneSynth(DroneSynth synth)
        {
            if (_synths.Contains(synth))
            {
                Debug.LogWarning("Synth already registered: " + synth.name);
                return;
            }

            _synths.Add(synth);

            synth.SetKeyAndScaleMode(_currentRootNote, _currentScaleMode);
            synth.SetLfoFrequency(_currentFrequency);
        }