diff --git a/firmware/application/io_wave.hpp b/firmware/application/io_wave.hpp
index 304d98e76..d315aadc9 100644
--- a/firmware/application/io_wave.hpp
+++ b/firmware/application/io_wave.hpp
@@ -31,12 +31,7 @@
 
 class WAVFileWriter : public FileWriter {
 public:
-	WAVFileWriter(
-		size_t sampling_rate
-	) : header { sampling_rate }
-	{
-	}
-
+	WAVFileWriter() = default;
 
 	WAVFileWriter(const WAVFileWriter&) = delete;
 	WAVFileWriter& operator=(const WAVFileWriter&) = delete;
@@ -48,8 +43,10 @@ public:
 	}
 
 	Optional<File::Error> create(
-		const std::filesystem::path& filename
+		const std::filesystem::path& filename,
+		size_t sampling_rate
 	) {
+		sampling_rate = sampling_rate;
 		const auto create_error = FileWriter::create(filename);
 		if( create_error.is_valid() ) {
 			return create_error;
@@ -68,50 +65,51 @@ private:
 		}
 
 	private:
-		const uint8_t ckID[4] { 'f', 'm', 't', ' ' };
-		const uint32_t cksize { 16 };
-		const uint16_t wFormatTag { 0x0001 };
-		const uint16_t nChannels { 1 };
-		const uint32_t nSamplesPerSec;
-		const uint32_t nAvgBytesPerSec;
-		const uint16_t nBlockAlign { 2 };
-		const uint16_t wBitsPerSample { 16 };
+		uint8_t ckID[4] { 'f', 'm', 't', ' ' };
+		uint32_t cksize { 16 };
+		uint16_t wFormatTag { 0x0001 };
+		uint16_t nChannels { 1 };
+		uint32_t nSamplesPerSec;
+		uint32_t nAvgBytesPerSec;
+		uint16_t nBlockAlign { 2 };
+		uint16_t wBitsPerSample { 16 };
 	};
 
 	struct data_t {
-		void set_size(const uint32_t value) {
-			cksize = value;
+		constexpr data_t(
+			const uint32_t size
+		) : cksize { size }
+		{
 		}
 
 	private:
-		const uint8_t ckID[4] { 'd', 'a', 't', 'a' };
+		uint8_t ckID[4] { 'd', 'a', 't', 'a' };
 		uint32_t cksize { 0 };
 	};
 
 	struct header_t {
 		constexpr header_t(
-			const uint32_t sampling_rate
-		) : fmt { sampling_rate }
+			const uint32_t sampling_rate,
+			const uint32_t data_chunk_size
+		) : cksize { sizeof(header_t) + data_chunk_size - 8 },
+			fmt { sampling_rate },
+			data { data_chunk_size }
 		{
 		}
 
-		void set_data_size(const uint32_t value) {
-			data.set_size(value);
-			cksize = sizeof(header_t) + value - 8;
-		}
-
 	private:
-		const uint8_t riff_id[4] { 'R', 'I', 'F', 'F' };
+		uint8_t riff_id[4] { 'R', 'I', 'F', 'F' };
 		uint32_t cksize { 0 };
-		const uint8_t wave_id[4] { 'W', 'A', 'V', 'E' };
+		uint8_t wave_id[4] { 'W', 'A', 'V', 'E' };
 		fmt_pcm_t fmt;
 		data_t data;
 	};
 
-	header_t header;
+	uint32_t sampling_rate;
+	uint32_t bytes_written;
 
 	Optional<File::Error> update_header() {
-		header.set_data_size(bytes_written);
+		header_t header { sampling_rate, bytes_written };
 		const auto seek_0_result = file.seek(0);
 		if( seek_0_result.is_error() ) {
 			return seek_0_result.error();
diff --git a/firmware/application/ui_record_view.cpp b/firmware/application/ui_record_view.cpp
index 60ff0ddb3..48d486591 100644
--- a/firmware/application/ui_record_view.cpp
+++ b/firmware/application/ui_record_view.cpp
@@ -121,10 +121,8 @@ void RecordView::start() {
 	switch(file_type) {
 	case FileType::WAV:
 		{
-			auto p = std::make_unique<WAVFileWriter>(
-				sampling_rate
-			);
-			auto create_error = p->create(base_path.replace_extension(u".WAV"));
+			auto p = std::make_unique<WAVFileWriter>();
+			auto create_error = p->create(base_path.replace_extension(u".WAV"), sampling_rate);
 			if( create_error.is_valid() ) {
 				handle_error(create_error.value());
 			} else {