diff --git a/libs/audio/include/psemek/audio/effect/envelope.hpp b/libs/audio/include/psemek/audio/effect/envelope_base.hpp
similarity index 76%
rename from libs/audio/include/psemek/audio/effect/envelope.hpp
rename to libs/audio/include/psemek/audio/effect/envelope_base.hpp
index b4607456..349f73f6 100644
--- a/libs/audio/include/psemek/audio/effect/envelope.hpp
+++ b/libs/audio/include/psemek/audio/effect/envelope_base.hpp
@@ -8,10 +8,10 @@ namespace psemek::audio
 	{
 
 		template <typename EnvelopeFn>
-		struct envelope_impl
+		struct envelope_base_impl
 			: stream
 		{
-			envelope_impl(stream_ptr stream, EnvelopeFn envelope_fn, std::optional<duration> truncate)
+			envelope_base_impl(stream_ptr stream, EnvelopeFn envelope_fn, std::optional<duration> truncate)
 				: stream_(std::move(stream))
 				, envelope_fn_(std::move(envelope_fn))
 				, remaining_(truncate ? std::optional{truncate->samples()} : std::nullopt)
@@ -59,9 +59,11 @@ namespace psemek::audio
 
 	}
 
+	// Guaranteed to call envelope_fn exactly once per audio frame
 	template <typename EnvelopeFn>
-	stream_ptr envelope(stream_ptr stream, EnvelopeFn envelope_fn, std::optional<duration> truncate = {})
+	stream_ptr envelope_base(stream_ptr stream, EnvelopeFn envelope_fn, std::optional<duration> truncate = {})
 	{
-		return std::make_shared<envelope_impl<EnvelopeFn>>(std::move(stream), std::move(envelope_fn), truncate);
+		return std::make_shared<envelope_base_impl<EnvelopeFn>>(std::move(stream), std::move(envelope_fn), truncate);
 	}
+
 }
diff --git a/libs/audio/source/effect/fade_in.cpp b/libs/audio/source/effect/fade_in.cpp
index 70980ebb..e242c401 100644
--- a/libs/audio/source/effect/fade_in.cpp
+++ b/libs/audio/source/effect/fade_in.cpp
@@ -1,5 +1,5 @@
 #include <psemek/audio/effect/fade_out.hpp>
-#include <psemek/audio/effect/envelope.hpp>
+#include <psemek/audio/effect/envelope_base.hpp>
 #include <psemek/math/interval.hpp>
 
 namespace psemek::audio
@@ -7,7 +7,7 @@ namespace psemek::audio
 
 	stream_ptr fade_in(stream_ptr stream, duration length, duration start)
 	{
-		return envelope(std::move(stream), [start, length](duration time){
+		return envelope_base(std::move(stream), [start, length](duration time){
 			return math::clamp(static_cast<float>(time.frames() - start.frames()) / length.frames(), {0.f, 1.f});
 		});
 	}
diff --git a/libs/audio/source/effect/fade_out.cpp b/libs/audio/source/effect/fade_out.cpp
index 53b7f29b..e19b89e2 100644
--- a/libs/audio/source/effect/fade_out.cpp
+++ b/libs/audio/source/effect/fade_out.cpp
@@ -1,5 +1,5 @@
 #include <psemek/audio/effect/fade_out.hpp>
-#include <psemek/audio/effect/envelope.hpp>
+#include <psemek/audio/effect/envelope_base.hpp>
 #include <psemek/math/interval.hpp>
 
 namespace psemek::audio
@@ -7,7 +7,7 @@ namespace psemek::audio
 
 	stream_ptr fade_out(stream_ptr stream, duration length, duration start)
 	{
-		return envelope(std::move(stream), [start, length](duration time){
+		return envelope_base(std::move(stream), [start, length](duration time){
 			return math::clamp(static_cast<float>(length.frames() + start.frames() - time.frames()) / length.frames(), {0.f, 1.f});
 		}, start + length);
 	}