diff --git a/src/AudioFormat.hxx b/src/AudioFormat.hxx
index 38d0aa9a6..469af2813 100644
--- a/src/AudioFormat.hxx
+++ b/src/AudioFormat.hxx
@@ -178,8 +178,8 @@ struct AudioFormat {
  *
  * @param sample_rate the sample rate in Hz
  */
-static constexpr inline bool
-audio_valid_sample_rate(unsigned sample_rate)
+constexpr bool
+audio_valid_sample_rate(unsigned sample_rate) noexcept
 {
 	return sample_rate > 0 && sample_rate < (1 << 30);
 }
@@ -187,8 +187,8 @@ audio_valid_sample_rate(unsigned sample_rate)
 /**
  * Checks whether the number of channels is valid.
  */
-static constexpr inline bool
-audio_valid_channel_count(unsigned channels)
+constexpr bool
+audio_valid_channel_count(unsigned channels) noexcept
 {
 	return channels >= 1 && channels <= MAX_CHANNELS;
 }
diff --git a/src/pcm/Dsd16.cxx b/src/pcm/Dsd16.cxx
index c93845893..5bed7948f 100644
--- a/src/pcm/Dsd16.cxx
+++ b/src/pcm/Dsd16.cxx
@@ -24,7 +24,7 @@
 /**
  * Construct a 16 bit integer from two bytes.
  */
-static constexpr inline uint16_t
+static constexpr uint16_t
 Construct16(uint8_t a, uint8_t b) noexcept
 {
 	/* "a" is the oldest byte, which must be in the most
@@ -33,7 +33,7 @@ Construct16(uint8_t a, uint8_t b) noexcept
 	return uint16_t(b) | (uint16_t(a) << 8);
 }
 
-static constexpr inline uint16_t
+static constexpr uint16_t
 Dsd8To16Sample(const uint8_t *src, unsigned channels) noexcept
 {
 	return Construct16(src[0], src[channels]);
diff --git a/src/pcm/Dsd32.cxx b/src/pcm/Dsd32.cxx
index 085654ade..749a0b44b 100644
--- a/src/pcm/Dsd32.cxx
+++ b/src/pcm/Dsd32.cxx
@@ -24,7 +24,7 @@
 /**
  * Construct a 32 bit integer from four bytes.
  */
-static constexpr inline uint32_t
+static constexpr uint32_t
 Construct32(uint8_t a, uint8_t b, uint8_t c, uint8_t d) noexcept
 {
 	/* "a" is the oldest byte, which must be in the most
@@ -34,7 +34,7 @@ Construct32(uint8_t a, uint8_t b, uint8_t c, uint8_t d) noexcept
 		(uint32_t(b) << 16) | (uint32_t(a) << 24);
 }
 
-static constexpr inline uint32_t
+static constexpr uint32_t
 Dsd8To32Sample(const uint8_t *src, unsigned channels) noexcept
 {
 	return Construct32(src[0], src[channels],
diff --git a/src/pcm/Volume.hxx b/src/pcm/Volume.hxx
index ddc6cb854..a5d53de7a 100644
--- a/src/pcm/Volume.hxx
+++ b/src/pcm/Volume.hxx
@@ -45,13 +45,13 @@ static constexpr int PCM_VOLUME_1S = PCM_VOLUME_1;
  * Converts a float value (0.0 = silence, 1.0 = 100% volume) to an
  * integer volume value (1000 = 100%).
  */
-static constexpr inline int
+constexpr int
 pcm_float_to_volume(float volume) noexcept
 {
 	return volume * PCM_VOLUME_1 + 0.5;
 }
 
-static constexpr inline float
+constexpr float
 pcm_volume_to_float(int volume) noexcept
 {
 	return (float)volume / (float)PCM_VOLUME_1;