diff --git a/src/core/EnvelopeAndLfoParameters.cpp b/src/core/EnvelopeAndLfoParameters.cpp
index 65a17f85a..44957eb15 100644
--- a/src/core/EnvelopeAndLfoParameters.cpp
+++ b/src/core/EnvelopeAndLfoParameters.cpp
@@ -118,7 +118,8 @@ EnvelopeAndLfoParameters::EnvelopeAndLfoParameters(
 	m_controlEnvAmountModel( false, this, tr( "Modulate env amount" ) ),
 	m_lfoFrame( 0 ),
 	m_lfoAmountIsZero( false ),
-	m_lfoShapeData( nullptr )
+	m_lfoShapeData( nullptr ),
+	m_userWave(std::make_shared<SampleBuffer>())
 {
 	m_amountModel.setCenterValue( 0 );
 	m_lfoAmountModel.setCenterValue( 0 );
@@ -221,7 +222,7 @@ inline sample_t EnvelopeAndLfoParameters::lfoShapeSample( fpp_t _frame_offset )
 			shape_sample = Oscillator::sawSample( phase );
 			break;
 		case LfoShape::UserDefinedWave:
-			shape_sample = Oscillator::userWaveSample(m_userWave.get(), phase);
+			shape_sample = Oscillator::userWaveSample(std::atomic_load(&m_userWave).get(), phase);
 			break;
 		case LfoShape::RandomWave:
 			if( frame == 0 )
@@ -354,7 +355,9 @@ void EnvelopeAndLfoParameters::saveSettings( QDomDocument & _doc,
 	m_lfoAmountModel.saveSettings( _doc, _parent, "lamt" );
 	m_x100Model.saveSettings( _doc, _parent, "x100" );
 	m_controlEnvAmountModel.saveSettings( _doc, _parent, "ctlenvamt" );
-	_parent.setAttribute("userwavefile", m_userWave->audioFile());
+
+	// TODO C++20: Deprecated, use std::atomic<std::shared_ptr> instead
+	_parent.setAttribute("userwavefile", std::atomic_load(&m_userWave)->audioFile());
 }
 
 
diff --git a/src/core/LfoController.cpp b/src/core/LfoController.cpp
index 2a6617bd2..a549f3a43 100644
--- a/src/core/LfoController.cpp
+++ b/src/core/LfoController.cpp
@@ -107,7 +107,8 @@ void LfoController::updateValueBuffer()
 	{
 		const float currentSample = m_sampleFunction != nullptr
 			? m_sampleFunction( phase )
-			: Oscillator::userWaveSample(m_userDefSampleBuffer.get(), phase);
+			// TODO C++20: Deprecated, use std::atomic<std::shared_ptr> instead
+			: Oscillator::userWaveSample(std::atomic_load(&m_userDefSampleBuffer).get(), phase);
 
 		f = std::clamp(m_baseModel.value() + (*amountPtr * currentSample / 2.0f), 0.0f, 1.0f);
 
diff --git a/src/core/Oscillator.cpp b/src/core/Oscillator.cpp
index 61643eb49..cd90a0bdc 100644
--- a/src/core/Oscillator.cpp
+++ b/src/core/Oscillator.cpp
@@ -814,7 +814,8 @@ inline sample_t Oscillator::getSample<Oscillator::WaveShape::UserDefined>(
 	}
 	else
 	{
-		return userWaveSample(m_userWave.get(), _sample);
+		// TODO C++20: Deprecated, use std::atomic<std::shared_ptr> instead
+		return userWaveSample(std::atomic_load(&m_userWave).get(), _sample);
 	}
 }
 
diff --git a/src/gui/instrument/EnvelopeAndLfoView.cpp b/src/gui/instrument/EnvelopeAndLfoView.cpp
index 04d96973c..dcf2decf0 100644
--- a/src/gui/instrument/EnvelopeAndLfoView.cpp
+++ b/src/gui/instrument/EnvelopeAndLfoView.cpp
@@ -486,7 +486,8 @@ void EnvelopeAndLfoView::paintEvent( QPaintEvent * )
 					val = m_randomGraph;
 					break;
 				case EnvelopeAndLfoParameters::LfoShape::UserDefinedWave:
-					val = Oscillator::userWaveSample(m_params->m_userWave.get(), phase);
+					// TODO C++20: Deprecated, use std::atomic<std::shared_ptr> instead
+					val = Oscillator::userWaveSample(std::atomic_load(&m_params->m_userWave).get(), phase);
 					break;
 			}
 			if( static_cast<f_cnt_t>( cur_sample ) <=