diff --git a/event/audio.go b/event/audio.go
index 0fc0818b..798acc8c 100644
--- a/event/audio.go
+++ b/event/audio.go
@@ -1,8 +1,8 @@
 package event
 
 type MSC1767Audio struct {
-	Duration int   `json:"duration,omitempty"`
-	Waveform []int `json:"waveform,omitempty"`
+	Duration int   `json:"duration"`
+	Waveform []int `json:"waveform"`
 }
 
 type MSC3245Voice struct{}