diff --git a/examples/audio.cpp b/examples/audio.cpp
index 884b0895..90a48c1a 100644
--- a/examples/audio.cpp
+++ b/examples/audio.cpp
@@ -10,12 +10,12 @@
 #include <psemek/audio/effect/fade_out.hpp>
 #include <psemek/audio/effect/compressor.hpp>
 #include <psemek/audio/effect/pause.hpp>
-#include <psemek/audio/effect/loop.hpp>
+#include <psemek/audio/combine/loop.hpp>
 #include <psemek/audio/effect/pitch.hpp>
 #include <psemek/audio/effect/distortion.hpp>
-#include <psemek/audio/duplicate.hpp>
-#include <psemek/audio/stereo.hpp>
-#include <psemek/audio/mixer.hpp>
+#include <psemek/audio/combine/duplicate.hpp>
+#include <psemek/audio/combine/stereo.hpp>
+#include <psemek/audio/combine/mixer.hpp>
 #include <psemek/app/app.hpp>
 #include <psemek/app/main.hpp>
 #include <psemek/gfx/painter.hpp>
diff --git a/examples/gravity.cpp b/examples/gravity.cpp
index e47f6165..4c156cdf 100644
--- a/examples/gravity.cpp
+++ b/examples/gravity.cpp
@@ -9,7 +9,7 @@
 #include <psemek/util/to_string.hpp>
 #include <psemek/audio/engine.hpp>
 #include <psemek/audio/constants.hpp>
-#include <psemek/audio/oscillator.hpp>
+#include <psemek/audio/detail/oscillator.hpp>
 #include <psemek/audio/effect/compressor.hpp>
 #include <psemek/prof/profiler.hpp>
 #include <psemek/util/moving_average.hpp>
diff --git a/libs/audio/include/psemek/audio/effect/concat.hpp b/libs/audio/include/psemek/audio/combine/concat.hpp
similarity index 100%
rename from libs/audio/include/psemek/audio/effect/concat.hpp
rename to libs/audio/include/psemek/audio/combine/concat.hpp
diff --git a/libs/audio/include/psemek/audio/duplicate.hpp b/libs/audio/include/psemek/audio/combine/duplicate.hpp
similarity index 100%
rename from libs/audio/include/psemek/audio/duplicate.hpp
rename to libs/audio/include/psemek/audio/combine/duplicate.hpp
diff --git a/libs/audio/include/psemek/audio/effect/loop.hpp b/libs/audio/include/psemek/audio/combine/loop.hpp
similarity index 100%
rename from libs/audio/include/psemek/audio/effect/loop.hpp
rename to libs/audio/include/psemek/audio/combine/loop.hpp
diff --git a/libs/audio/include/psemek/audio/mixer.hpp b/libs/audio/include/psemek/audio/combine/mixer.hpp
similarity index 100%
rename from libs/audio/include/psemek/audio/mixer.hpp
rename to libs/audio/include/psemek/audio/combine/mixer.hpp
diff --git a/libs/audio/include/psemek/audio/stereo.hpp b/libs/audio/include/psemek/audio/combine/stereo.hpp
similarity index 100%
rename from libs/audio/include/psemek/audio/stereo.hpp
rename to libs/audio/include/psemek/audio/combine/stereo.hpp
diff --git a/libs/audio/include/psemek/audio/oscillator.hpp b/libs/audio/include/psemek/audio/detail/oscillator.hpp
similarity index 100%
rename from libs/audio/include/psemek/audio/oscillator.hpp
rename to libs/audio/include/psemek/audio/detail/oscillator.hpp
diff --git a/libs/audio/include/psemek/audio/resampler.hpp b/libs/audio/include/psemek/audio/detail/resampler.hpp
similarity index 100%
rename from libs/audio/include/psemek/audio/resampler.hpp
rename to libs/audio/include/psemek/audio/detail/resampler.hpp
diff --git a/libs/audio/include/psemek/audio/smooth.hpp b/libs/audio/include/psemek/audio/detail/smooth.hpp
similarity index 100%
rename from libs/audio/include/psemek/audio/smooth.hpp
rename to libs/audio/include/psemek/audio/detail/smooth.hpp
diff --git a/libs/audio/include/psemek/audio/white_noise.hpp b/libs/audio/include/psemek/audio/detail/white_noise.hpp
similarity index 100%
rename from libs/audio/include/psemek/audio/white_noise.hpp
rename to libs/audio/include/psemek/audio/detail/white_noise.hpp
diff --git a/libs/audio/source/effect/concat.cpp b/libs/audio/source/combine/concat.cpp
similarity index 96%
rename from libs/audio/source/effect/concat.cpp
rename to libs/audio/source/combine/concat.cpp
index 4497a2a9..907d978d 100644
--- a/libs/audio/source/effect/concat.cpp
+++ b/libs/audio/source/combine/concat.cpp
@@ -1,4 +1,4 @@
-#include <psemek/audio/effect/concat.hpp>
+#include <psemek/audio/combine/concat.hpp>
 
 #include <atomic>
 
diff --git a/libs/audio/source/duplicate.cpp b/libs/audio/source/combine/duplicate.cpp
similarity index 95%
rename from libs/audio/source/duplicate.cpp
rename to libs/audio/source/combine/duplicate.cpp
index 6219e694..74f7f56c 100644
--- a/libs/audio/source/duplicate.cpp
+++ b/libs/audio/source/combine/duplicate.cpp
@@ -1,5 +1,4 @@
-#include <psemek/audio/duplicate.hpp>
-#include <psemek/audio/recorder.hpp>
+#include <psemek/audio/combine/duplicate.hpp>
 
 #include <atomic>
 
diff --git a/libs/audio/source/effect/loop.cpp b/libs/audio/source/combine/loop.cpp
similarity index 93%
rename from libs/audio/source/effect/loop.cpp
rename to libs/audio/source/combine/loop.cpp
index b4e356c9..5804c76f 100644
--- a/libs/audio/source/effect/loop.cpp
+++ b/libs/audio/source/combine/loop.cpp
@@ -1,5 +1,5 @@
-#include <psemek/audio/effect/loop.hpp>
-#include <psemek/audio/duplicate.hpp>
+#include <psemek/audio/combine/loop.hpp>
+#include <psemek/audio/combine/duplicate.hpp>
 
 namespace psemek::audio
 {
diff --git a/libs/audio/source/mixer.cpp b/libs/audio/source/combine/mixer.cpp
similarity index 97%
rename from libs/audio/source/mixer.cpp
rename to libs/audio/source/combine/mixer.cpp
index 146dab97..749f6fb3 100644
--- a/libs/audio/source/mixer.cpp
+++ b/libs/audio/source/combine/mixer.cpp
@@ -1,4 +1,4 @@
-#include <psemek/audio/mixer.hpp>
+#include <psemek/audio/combine/mixer.hpp>
 
 #include <memory>
 #include <vector>
diff --git a/libs/audio/source/stereo.cpp b/libs/audio/source/combine/stereo.cpp
similarity index 96%
rename from libs/audio/source/stereo.cpp
rename to libs/audio/source/combine/stereo.cpp
index c6671c78..dc19f65f 100644
--- a/libs/audio/source/stereo.cpp
+++ b/libs/audio/source/combine/stereo.cpp
@@ -1,4 +1,4 @@
-#include <psemek/audio/stereo.hpp>
+#include <psemek/audio/combine/stereo.hpp>
 
 #include <vector>
 
diff --git a/libs/audio/source/resampler.cpp b/libs/audio/source/detail/resampler.cpp
similarity index 95%
rename from libs/audio/source/resampler.cpp
rename to libs/audio/source/detail/resampler.cpp
index 1bd943d7..27f76b16 100644
--- a/libs/audio/source/resampler.cpp
+++ b/libs/audio/source/detail/resampler.cpp
@@ -1,5 +1,5 @@
-#include <psemek/audio/resampler.hpp>
-#include <psemek/audio/smooth.hpp>
+#include <psemek/audio/detail/resampler.hpp>
+#include <psemek/audio/detail/smooth.hpp>
 #include <psemek/geom/math.hpp>
 
 #include <psemek/log/log.hpp>
diff --git a/libs/audio/source/white_noise.cpp b/libs/audio/source/detail/white_noise.cpp
similarity index 88%
rename from libs/audio/source/white_noise.cpp
rename to libs/audio/source/detail/white_noise.cpp
index b450013b..b1e9a1c8 100644
--- a/libs/audio/source/white_noise.cpp
+++ b/libs/audio/source/detail/white_noise.cpp
@@ -1,4 +1,4 @@
-#include <psemek/audio/white_noise.hpp>
+#include <psemek/audio/detail/white_noise.hpp>
 
 #include <psemek/random/generator.hpp>
 #include <psemek/random/uniform.hpp>
diff --git a/libs/audio/source/effect/compressor.cpp b/libs/audio/source/effect/compressor.cpp
index 0478027f..de02c96c 100644
--- a/libs/audio/source/effect/compressor.cpp
+++ b/libs/audio/source/effect/compressor.cpp
@@ -1,5 +1,5 @@
 #include <psemek/audio/effect/compressor.hpp>
-#include <psemek/audio/smooth.hpp>
+#include <psemek/audio/detail/smooth.hpp>
 #include <psemek/geom/math.hpp>
 #include <psemek/geom/interval.hpp>
 #include <psemek/geom/contains.hpp>
diff --git a/libs/audio/source/effect/pause.cpp b/libs/audio/source/effect/pause.cpp
index 402e496a..d60453e0 100644
--- a/libs/audio/source/effect/pause.cpp
+++ b/libs/audio/source/effect/pause.cpp
@@ -1,5 +1,5 @@
 #include <psemek/audio/effect/pause.hpp>
-#include <psemek/audio/smooth.hpp>
+#include <psemek/audio/detail/smooth.hpp>
 
 #include <atomic>
 
diff --git a/libs/audio/source/effect/pitch.cpp b/libs/audio/source/effect/pitch.cpp
index c3b2dbdf..a1ccbfb8 100644
--- a/libs/audio/source/effect/pitch.cpp
+++ b/libs/audio/source/effect/pitch.cpp
@@ -1,5 +1,5 @@
 #include <psemek/audio/effect/pitch.hpp>
-#include <psemek/audio/resampler.hpp>
+#include <psemek/audio/detail/resampler.hpp>
 
 #include <cmath>
 
diff --git a/libs/audio/source/effect/volume_base.cpp b/libs/audio/source/effect/volume_base.cpp
index e050cf79..95552d0f 100644
--- a/libs/audio/source/effect/volume_base.cpp
+++ b/libs/audio/source/effect/volume_base.cpp
@@ -1,6 +1,6 @@
 #include <psemek/audio/effect/volume_base.hpp>
 #include <psemek/audio/constants.hpp>
-#include <psemek/audio/smooth.hpp>
+#include <psemek/audio/detail/smooth.hpp>
 
 #include <psemek/log/log.hpp>
 
diff --git a/libs/audio/source/track_mp3.cpp b/libs/audio/source/track_mp3.cpp
index dc98dc82..da458094 100644
--- a/libs/audio/source/track_mp3.cpp
+++ b/libs/audio/source/track_mp3.cpp
@@ -1,5 +1,5 @@
 #include <psemek/audio/track.hpp>
-#include <psemek/audio/resampler.hpp>
+#include <psemek/audio/detail/resampler.hpp>
 #include <psemek/audio/constants.hpp>
 
 #include <psemek/audio/minimp3/options.h>
diff --git a/libs/audio/source/track_raw.cpp b/libs/audio/source/track_raw.cpp
index eafe3701..e0eb9def 100644
--- a/libs/audio/source/track_raw.cpp
+++ b/libs/audio/source/track_raw.cpp
@@ -1,5 +1,5 @@
 #include <psemek/audio/track.hpp>
-#include <psemek/audio/duplicate.hpp>
+#include <psemek/audio/combine/duplicate.hpp>
 
 namespace psemek::audio
 {
diff --git a/libs/audio/source/track_wav.cpp b/libs/audio/source/track_wav.cpp
index 5faa10cc..a0d4527d 100644
--- a/libs/audio/source/track_wav.cpp
+++ b/libs/audio/source/track_wav.cpp
@@ -1,5 +1,5 @@
 #include <psemek/audio/track.hpp>
-#include <psemek/audio/duplicate.hpp>
+#include <psemek/audio/combine/duplicate.hpp>
 #include <psemek/audio/constants.hpp>
 #include <psemek/util/to_string.hpp>
 #include <psemek/util/at_scope_exit.hpp>
diff --git a/libs/audio/source/wave/karplus_strong.cpp b/libs/audio/source/wave/karplus_strong.cpp
index 26641cff..57b62c62 100644
--- a/libs/audio/source/wave/karplus_strong.cpp
+++ b/libs/audio/source/wave/karplus_strong.cpp
@@ -1,6 +1,6 @@
 #include <psemek/audio/wave/karplus_strong.hpp>
 #include <psemek/audio/constants.hpp>
-#include <psemek/audio/white_noise.hpp>
+#include <psemek/audio/detail/white_noise.hpp>
 #include <psemek/random/generator.hpp>
 #include <psemek/random/uniform.hpp>
 
diff --git a/libs/audio/source/wave/sawtooth.cpp b/libs/audio/source/wave/sawtooth.cpp
index 3e74c08f..885dde51 100644
--- a/libs/audio/source/wave/sawtooth.cpp
+++ b/libs/audio/source/wave/sawtooth.cpp
@@ -1,6 +1,6 @@
 #include <psemek/audio/wave/sawtooth.hpp>
 #include <psemek/audio/wave/generator.hpp>
-#include <psemek/audio/oscillator.hpp>
+#include <psemek/audio/detail/oscillator.hpp>
 #include <psemek/log/log.hpp>
 
 #include <cmath>
diff --git a/libs/audio/source/wave/sine.cpp b/libs/audio/source/wave/sine.cpp
index 0c3d8bd7..c3f0ded4 100644
--- a/libs/audio/source/wave/sine.cpp
+++ b/libs/audio/source/wave/sine.cpp
@@ -1,6 +1,6 @@
 #include <psemek/audio/wave/sine.hpp>
 #include <psemek/audio/wave/generator.hpp>
-#include <psemek/audio/oscillator.hpp>
+#include <psemek/audio/detail/oscillator.hpp>
 
 #include <cmath>
 #include <complex>
diff --git a/libs/audio/source/wave/square.cpp b/libs/audio/source/wave/square.cpp
index 8d96ca51..c61d0d7a 100644
--- a/libs/audio/source/wave/square.cpp
+++ b/libs/audio/source/wave/square.cpp
@@ -1,6 +1,6 @@
 #include <psemek/audio/wave/square.hpp>
 #include <psemek/audio/wave/generator.hpp>
-#include <psemek/audio/oscillator.hpp>
+#include <psemek/audio/detail/oscillator.hpp>
 
 #include <cmath>
 
diff --git a/libs/audio/source/wave/triangle.cpp b/libs/audio/source/wave/triangle.cpp
index 54d97c22..7fd997f0 100644
--- a/libs/audio/source/wave/triangle.cpp
+++ b/libs/audio/source/wave/triangle.cpp
@@ -1,6 +1,6 @@
 #include <psemek/audio/wave/triangle.hpp>
 #include <psemek/audio/wave/generator.hpp>
-#include <psemek/audio/oscillator.hpp>
+#include <psemek/audio/detail/oscillator.hpp>
 
 #include <cmath>