diff --git a/doc/4-instrument/saa.md b/doc/4-instrument/saa.md
index 1611bd61c..f005261b4 100644
--- a/doc/4-instrument/saa.md
+++ b/doc/4-instrument/saa.md
@@ -9,4 +9,12 @@ The SAA1099 instrument editor consists of these macros:
 - **Panning (left)**: output level for left channel
 - **Panning (right)**: output level for right channel
 - **Pitch**: fine pitch
-- **Envelope**: envelope generator shape
+- **Envelope**: envelope generator settings:
+  enable: enables the envelope generator
+  N/A: has no effect
+  fixed: toggles whether to use a fixed frequency or lock to the frequency of channel 2 or 5
+  resolution: increases the envelope generator pitch resolution
+  direction: inverts the waveform around Y axis
+  cut: cuts the waveform (producing saw wave out of tri wave)
+  loop: toggles wheteher evelope is one-off or constantly looping
+  mirror: sets whether the right output will mirror the left one