diff --git a/src/board/audio/index.ts b/src/board/audio/index.ts
index 6473ae0a..5278eab9 100644
--- a/src/board/audio/index.ts
+++ b/src/board/audio/index.ts
@@ -200,7 +200,7 @@ export class BoardAudio {
     //       what sample rates are actually supported this way?
     const recorder = this.context!.createScriptProcessor(2048, 1, 1);
     recorder.onaudioprocess = (e) => {
-      const offlineContext = new (OfflineAudioContext ||
+      const offlineContext = new (window.OfflineAudioContext ||
         window.webkitOfflineAudioContext)({
         sampleRate,
         length: sampleRate * (e.inputBuffer.length / e.inputBuffer.sampleRate),