diff --git a/src/core/RoundManager.cpp b/src/core/RoundManager.cpp
index 93d6714..86dce75 100644
--- a/src/core/RoundManager.cpp
+++ b/src/core/RoundManager.cpp
@@ -13,7 +13,7 @@
 #include "DomeRenderer.h"
 #include "Logging.h"
 
-RoundController::RoundController(RoundConfig config,
+RoundController::RoundController(RoundConfig& config,
                                  BleepoutParameters& appParams,
                                  std::list<ofPtr<Player> > players,
                                  PlayerManager& playerManager)
diff --git a/src/core/RoundManager.h b/src/core/RoundManager.h
index 22b3bfd..f8b7ada 100644
--- a/src/core/RoundManager.h
+++ b/src/core/RoundManager.h
@@ -26,7 +26,7 @@ class RendererBase;
 class RoundController : public EventSource
 {
 public:
-  RoundController(RoundConfig config,
+  RoundController(RoundConfig& config,
                   BleepoutParameters& appParams,
                   std::list<ofPtr<Player> > players,
                   PlayerManager& playerManager);
@@ -79,7 +79,7 @@ class RoundController : public EventSource
   float _startTime;
   BleepoutParameters& _appParams;
   PlayerManager& _playerManager;
-  RoundConfig _config;
+  RoundConfig& _config;
   RoundState _state;
   ofPtr<RendererBase> _renderer;
   ofPtr<SpaceController> _spaceController;
diff --git a/src/game_objects/Ball.cpp b/src/game_objects/Ball.cpp
index bfd9aed..54c30c6 100644
--- a/src/game_objects/Ball.cpp
+++ b/src/game_objects/Ball.cpp
@@ -14,22 +14,20 @@
 
 const char GameObjectTypeTraits<Ball>::typeName[] = "ball";
 
-Ball::Ball(const RoundConfig* config /*= NULL*/, const BallSpec* spec /*= NULL*/)
+Ball::Ball(const RoundConfig& config, const BallSpec& spec)
 : GameObject(GAME_OBJECT_BALL)
 , _player(NULL)
 , PhysicsObject(CollisionSphere)
 {
     thisGameObject = this;
-    _color = ofColor(220, 220, 220);
-    if (config && spec) {
-        this->setSize(ofVec3f(config->ballRadius()));
-        auto t = new OrbitalTrajectory();
-        t->setRadius(config->domeRadius() + config->domeMargin());
-        t->setSpeed(0.03);
-        t->initWithTwoPoints(spec->elevation, spec->heading, -14,
-                             spec->heading + ofRandom(-45, 45));
-        this->setTrajectory(t);
-    }
+  _color = ofColor(220, 220, 220);
+  this->setSize(ofVec3f(config.ballRadius()));
+  auto t = new OrbitalTrajectory();
+  t->setRadius(config.domeRadius() + config.domeMargin());
+  t->setSpeed(0.03);
+  t->initWithTwoPoints(spec.elevation, spec.heading, -14,
+                       spec.heading + ofRandom(-45, 45));
+  this->setTrajectory(t);
 }
 
 void Ball::bounce(ofVec3f normal, float trueHitFactor /* = 0.0 */) {
diff --git a/src/game_objects/Ball.h b/src/game_objects/Ball.h
index 037d9b6..2acb5e3 100644
--- a/src/game_objects/Ball.h
+++ b/src/game_objects/Ball.h
@@ -21,7 +21,7 @@ struct BallSpec;
 
 class Ball : public GameObject, public PhysicsObject {
 public:
-  Ball(const RoundConfig* config = NULL, const BallSpec* spec = NULL);
+  Ball(const RoundConfig& config, const BallSpec& spec);
   
   Player* player() { return _player; }
   const Player* player() const { return _player; }
diff --git a/src/game_objects/GameState.cpp b/src/game_objects/GameState.cpp
index 2aa41e7..f4454d8 100644
--- a/src/game_objects/GameState.cpp
+++ b/src/game_objects/GameState.cpp
@@ -53,7 +53,7 @@ Wall& RoundState::addWall(const WallSpec& wallSpec) {
 }
 
 Ball& RoundState::addBall(const BallSpec& ballSpec) {
-  ofPtr<Ball> ball(new Ball(&_config, &ballSpec));
+  ofPtr<Ball> ball(new Ball(_config, ballSpec));
   _balls.push_back(ball);
   return *ball;
 }