    //=============================================================================
    //  MuseScore
    //  Music Composition & Notation
    //
    //  Copyright (C) 2002-2012 Werner Schweer
    //
    //  This program is free software; you can redistribute it and/or modify
    //  it under the terms of the GNU General Public License version 2
    //  as published by the Free Software Foundation and appearing in
    //  the file LICENCE.GPL
    //=============================================================================

    #ifndef __SYNTHESIZER_H__
    #define __SYNTHESIZER_H__

    #include "libmscore/synthesizerstate.h"

    namespace Ms {

    struct MidiPatch;
    class PlayEvent;
    class Synth;
    class SynthesizerGui;

    //---------------------------------------------------------
    //   Synthesizer
    //---------------------------------------------------------

    class Synthesizer {
          bool _active;

       protected:
          float _sampleRate;
          SynthesizerGui* _gui;

       public:
          Synthesizer() : _active(false) { _gui = 0; }
          virtual ~Synthesizer() {}
          virtual void init(float sr)    { _sampleRate = sr; }
          float sampleRate() const       { return _sampleRate; }

          virtual const char* name() const = 0;

          virtual void setMasterTuning(double) {}
          virtual double masterTuning() const { return 440.0; }

          virtual bool loadSoundFonts(const QStringList&) = 0;
          virtual bool addSoundFont(const QString&)    { return false; }
          virtual bool removeSoundFont(const QString&) { return false; }

          virtual QStringList soundFonts() const = 0;

          virtual void process(unsigned, float*, float*, float*) = 0;
          virtual void play(const PlayEvent&) = 0;

          virtual const QList<MidiPatch*>& getPatchInfo() const = 0;

          // get/set synthesizer state
          virtual SynthesizerGroup state() const = 0;
          virtual bool setState(const SynthesizerGroup&) = 0;
          virtual void setValue(int, double) {}
          virtual double value(int) const { return 0.0; }

          void reset()                    { _active = false; }
          bool active() const             { return _active; }
          void setActive(bool val = true) { _active = val;  }

          virtual void allSoundsOff(int /*channel*/) {}
          virtual void allNotesOff(int /*channel*/) {}

          virtual SynthesizerGui* gui()  { return _gui; }
          };

    }
    #endif

↑ V730 Not all members of a class are initialized inside the constructor. Consider inspecting: _sampleRate.