diff --git a/src/client/app/common/views/components/messaging-room.vue b/src/client/app/common/views/components/messaging-room.vue
index d30c64d74..e1b775c33 100644
--- a/src/client/app/common/views/components/messaging-room.vue
+++ b/src/client/app/common/views/components/messaging-room.vue
@@ -151,7 +151,7 @@ export default Vue.extend({
 			// サウンドを再生する
 			if ((this as any).os.isEnableSounds) {
 				const sound = new Audio(`${url}/assets/message.mp3`);
-				sound.volume = localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) / 100 : 1;
+				sound.volume = localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) / 100 : 0.5;
 				sound.play();
 			}
 
diff --git a/src/client/app/common/views/components/othello.game.vue b/src/client/app/common/views/components/othello.game.vue
index b9d946de9..8c646cce0 100644
--- a/src/client/app/common/views/components/othello.game.vue
+++ b/src/client/app/common/views/components/othello.game.vue
@@ -164,7 +164,7 @@ export default Vue.extend({
 			// サウンドを再生する
 			if ((this as any).os.isEnableSounds) {
 				const sound = new Audio(`${url}/assets/othello-put-me.mp3`);
-				sound.volume = localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) / 100 : 1;
+				sound.volume = localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) / 100 : 0.5;
 				sound.play();
 			}
 
@@ -188,7 +188,7 @@ export default Vue.extend({
 			// サウンドを再生する
 			if ((this as any).os.isEnableSounds && x.color != this.myColor) {
 				const sound = new Audio(`${url}/assets/othello-put-you.mp3`);
-				sound.volume = localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) / 100 : 1;
+				sound.volume = localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) / 100 : 0.5;
 				sound.play();
 			}
 		},
diff --git a/src/client/app/desktop/views/components/settings.vue b/src/client/app/desktop/views/components/settings.vue
index 2b5aa3024..9d074165e 100644
--- a/src/client/app/desktop/views/components/settings.vue
+++ b/src/client/app/desktop/views/components/settings.vue
@@ -230,7 +230,7 @@ export default Vue.extend({
 			enableSounds: localStorage.getItem('enableSounds') == 'true',
 			autoPopout: localStorage.getItem('autoPopout') == 'true',
 			apiViaStream: localStorage.getItem('apiViaStream') ? localStorage.getItem('apiViaStream') == 'true' : true,
-			soundVolume: localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) : 100,
+			soundVolume: localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) : 50,
 			lang: localStorage.getItem('lang') || '',
 			preventUpdate: localStorage.getItem('preventUpdate') == 'true',
 			debug: localStorage.getItem('debug') == 'true',
@@ -347,7 +347,7 @@ export default Vue.extend({
 		},
 		soundTest() {
 			const sound = new Audio(`${url}/assets/message.mp3`);
-			sound.volume = localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) / 100 : 1;
+			sound.volume = localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) / 100 : 0.5;
 			sound.play();
 		}
 	}
diff --git a/src/client/app/desktop/views/components/timeline.vue b/src/client/app/desktop/views/components/timeline.vue
index e1f88b62f..f148e840a 100644
--- a/src/client/app/desktop/views/components/timeline.vue
+++ b/src/client/app/desktop/views/components/timeline.vue
@@ -97,7 +97,7 @@ export default Vue.extend({
 			// サウンドを再生する
 			if ((this as any).os.isEnableSounds) {
 				const sound = new Audio(`${url}/assets/post.mp3`);
-				sound.volume = localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) / 100 : 1;
+				sound.volume = localStorage.getItem('soundVolume') ? parseInt(localStorage.getItem('soundVolume'), 10) / 100 : 0.5;
 				sound.play();
 			}