diff --git a/internal/delivery/voicesink/voicesink.go b/internal/delivery/voicesink/voicesink.go
index 4f49e6f..bfcb783 100644
--- a/internal/delivery/voicesink/voicesink.go
+++ b/internal/delivery/voicesink/voicesink.go
@@ -34,7 +34,6 @@ import (
 	"log"
 	"time"
 
-	"github.com/kami/maven/internal/audio"
 	"github.com/kami/maven/internal/delivery"
 	"github.com/kami/maven/internal/tts"
 	"github.com/kami/maven/internal/ttsnorm"
@@ -102,9 +101,3 @@ func (s *Sink) Send(ctx context.Context, send delivery.Sendable) error {
 	}
 	return nil
 }
-
-// keep audio import honest (used in Send's audio.PCM check indirect via
-// Format.IsValid which is a method on the imported audio.Format). The alias
-// below keeps the import alive even if a future refactor moves the only
-// reference. Today, the synthesizer's audio.Audio directly flows through.
-var _ = audio.PCM16kMono