diff --git a/libs/audio/include/psemek/audio/combine/duplicate.hpp b/libs/audio/include/psemek/audio/combine/duplicate.hpp
index 491a2eab..f55a673d 100644
--- a/libs/audio/include/psemek/audio/combine/duplicate.hpp
+++ b/libs/audio/include/psemek/audio/combine/duplicate.hpp
@@ -10,16 +10,7 @@ namespace psemek::audio
 {
 
 	track_ptr make_duplicator(std::shared_ptr<recorder> recorder);
-
-	inline track_ptr make_duplicator(stream_ptr stream)
-	{
-		return make_duplicator(make_recorder(std::move(stream)));
-	}
-
-	inline std::pair<stream_ptr, stream_ptr> duplicate(stream_ptr stream)
-	{
-		auto track = make_duplicator(std::move(stream));
-		return {track->stream(), track->stream()};
-	}
+	track_ptr make_duplicator(stream_ptr stream);
+	std::pair<stream_ptr, stream_ptr> duplicate(stream_ptr stream);
 
 }
diff --git a/libs/audio/include/psemek/audio/recorder.hpp b/libs/audio/include/psemek/audio/recorder.hpp
index f25b20e9..10cf9d80 100644
--- a/libs/audio/include/psemek/audio/recorder.hpp
+++ b/libs/audio/include/psemek/audio/recorder.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <psemek/audio/stream.hpp>
+#include <psemek/audio/channel.hpp>
 #include <psemek/util/span.hpp>
 
 #include <vector>
@@ -10,17 +11,18 @@ namespace psemek::audio
 
 	struct recorder
 	{
-		virtual std::optional<std::size_t> length() const = 0;
+		virtual channel_ptr channel() = 0;
 
 		virtual std::size_t request(std::size_t samples) = 0;
 
 		virtual util::span<float const> buffer() const = 0;
 
+		virtual std::vector<float> grab_buffer() = 0;
+
 		virtual ~recorder() {}
 	};
 
+	std::shared_ptr<recorder> make_recorder();
 	std::shared_ptr<recorder> make_recorder(stream_ptr stream);
-	std::shared_ptr<recorder> make_recorder(std::vector<float> samples);
-	std::shared_ptr<recorder> make_recorder(util::span<float const> samples);
 
 }
diff --git a/libs/audio/source/combine/duplicate.cpp b/libs/audio/source/combine/duplicate.cpp
index 74f7f56c..c8f921d0 100644
--- a/libs/audio/source/combine/duplicate.cpp
+++ b/libs/audio/source/combine/duplicate.cpp
@@ -17,7 +17,7 @@ namespace psemek::audio
 
 			std::optional<std::size_t> length() const override
 			{
-				return recorder_->length();
+				return recorder_->channel()->stream()->length();
 			}
 
 			std::size_t played() const override
@@ -60,7 +60,7 @@ namespace psemek::audio
 
 			std::optional<std::size_t> length() const override
 			{
-				return recorder_->length();
+				return recorder_->channel()->stream()->length();
 			}
 
 		private:
@@ -74,4 +74,15 @@ namespace psemek::audio
 		return std::make_shared<duplicate_track_impl>(std::move(recorder));
 	}
 
+	track_ptr make_duplicator(stream_ptr stream)
+	{
+		return make_duplicator(make_recorder(std::move(stream)));
+	}
+
+	std::pair<stream_ptr, stream_ptr> duplicate(stream_ptr stream)
+	{
+		auto track = make_duplicator(std::move(stream));
+		return {track->stream(), track->stream()};
+	}
+
 }
diff --git a/libs/audio/source/recorder.cpp b/libs/audio/source/recorder.cpp
index 74e76f2b..87a260a9 100644
--- a/libs/audio/source/recorder.cpp
+++ b/libs/audio/source/recorder.cpp
@@ -11,38 +11,36 @@ namespace psemek::audio
 		struct recorder_impl
 			: recorder
 		{
-			recorder_impl(stream_ptr stream)
-				: stream_(std::move(stream))
+			recorder_impl()
+				: channel_(std::make_shared<audio::channel>())
 			{}
 
-			recorder_impl(std::vector<float> samples)
-				: storage_(std::move(samples))
-				, samples_(storage_)
-			{}
-
-			recorder_impl(util::span<float const> samples)
-				: samples_(samples)
-			{}
-
-			std::optional<std::size_t> length() const override
+			channel_ptr channel() override
 			{
-				return stream_ ? stream_->length() : storage_.size();
+				return channel_;
 			}
 
-			std::size_t request(std::size_t samples) override
+			std::size_t request(std::size_t sample_count) override
 			{
-				if (!stream_)
-					return 0;
+				std::size_t count = 0;
 
-				if (storage_.size() < samples_.size() + samples)
+				if (storage_.size() < samples_.size() + sample_count)
 				{
-					storage_.resize(std::max<std::size_t>(samples, storage_.size() * 2));
+					storage_.resize(std::max<std::size_t>(sample_count, storage_.size() * 2));
 					samples_ = {storage_.data(), storage_.data() + samples_.size()};
 				}
 
-				auto count = stream_->read({storage_.data() + samples_.size(), samples});
-				samples_ = {storage_.data(), storage_.data() + samples_.size() + count};
-				return count;
+				if (auto stream = channel_->stream())
+				{
+					count = stream->read({storage_.data() + samples_.size(), sample_count});
+					if (count < sample_count)
+						channel_->stop();
+				}
+
+				std::fill(storage_.data() + samples_.size() + count, storage_.data() + samples_.size() + sample_count, 0.f);
+				samples_ = {storage_.data(), storage_.data() + samples_.size() + sample_count};
+
+				return sample_count;
 			}
 
 			util::span<float const> buffer() const override
@@ -50,31 +48,31 @@ namespace psemek::audio
 				return samples_;
 			}
 
+			std::vector<float> grab_buffer() override
+			{
+				storage_.resize(samples_.size());
+				samples_ = {};
+				return std::move(storage_);
+			}
+
 		private:
-			stream_ptr stream_;
+			channel_ptr channel_;
 			std::vector<float> storage_;
 			util::span<float const> samples_;
 		};
 
 	}
 
+	std::shared_ptr<recorder> make_recorder()
+	{
+		return std::make_shared<recorder_impl>();
+	}
+
 	std::shared_ptr<recorder> make_recorder(stream_ptr stream)
 	{
-		return std::make_shared<recorder_impl>(std::move(stream));
-	}
-
-	std::shared_ptr<recorder> make_recorder(std::vector<float> samples)
-	{
-		if ((samples.size() % 2) != 0)
-			throw std::runtime_error("bad sample count");
-		return std::make_shared<recorder_impl>(std::move(samples));
-	}
-
-	std::shared_ptr<recorder> make_recorder(util::span<float const> samples)
-	{
-		if ((samples.size() % 2) != 0)
-			throw std::runtime_error("bad sample count");
-		return std::make_shared<recorder_impl>(samples);
+		auto recorder = make_recorder();
+		recorder->channel()->stream(std::move(stream));
+		return recorder;
 	}
 
 }