diff --git a/index.html b/index.html
index d0234fb..787b999 100644
--- a/index.html
+++ b/index.html
@@ -16,7 +16,7 @@
     <main id="app" style="display:none">
         <h1>Startle Machine</h1>
         <p>Generates silence occasionally broken up by random sound effects.<br>Click the button below and leave this tab to start the prank.</p>
-        <button class="start" :disabled="started" @click="start">{{ started ? 'You can leave this tab now...' : 'Start the prank' }}</button>
+        <button class="start" :disabled="started || !canStart" @click="start">{{ started ? 'You can leave this tab now...' : (canStart ? 'Start the prank' : 'Select at least one sound') }}</button>
         <br>
         <h2>Configuration</h2>
         <table class="config">
@@ -27,12 +27,12 @@
             </colgroup>
             <tr>
                 <td><label for="minDelay">Minimum delay:</label></td>
-                <td><input id="minDelay" type="range" v-model="minDelay" min="1" max="120" /></td>
+                <td><input id="minDelay" type="range" v-model="minDelay" min="1" max="60" /></td>
                 <td>{{ minDelay }} minutes</td>
             </tr>
             <tr>
                 <td><label for="maxDelay">Maximum delay:</label></td>
-                <td><input id="maxDelay" type="range" v-model="maxDelay" min="1" max="120" /></td>
+                <td><input id="maxDelay" type="range" v-model="maxDelay" min="1" max="60" /></td>
                 <td>{{ maxDelay }} minutes</td>
             </tr>
             <tr>
diff --git a/main.js b/main.js
index dfd75f2..4b47a68 100644
--- a/main.js
+++ b/main.js
@@ -65,8 +65,8 @@ let app = {
     return {
       sounds: [],
       started: false,
-      minDelay: 15,
-      maxDelay: 45,
+      minDelay: 5,
+      maxDelay: 10,
       volume: 50,
       randomPitch: true,
       hidePrank: true,
@@ -75,7 +75,11 @@ let app = {
       fakes: FAKES,
     };
   },
-  computed: {},
+  computed: {
+    canStart() {
+      return this.sounds.filter(sound => sound.active).length > 0;
+    },
+  },
   watch: {
     minDelay() {
       this.maxDelay = Math.max(this.minDelay, this.maxDelay);
@@ -146,9 +150,9 @@ let app = {
     },
     trigger() {
       this.started = true;
-      const time = random.int(this.minDelay, this.maxDelay);
-      console.log(`Next in ${time} minutes`);
-      setTimeout(this.playRandomSound, time * 60 * 1000);
+      const time = random.int(this.minDelay * 60 * 1000, this.maxDelay * 60 * 1000);
+      console.log(`Next in ${Math.round(time / (60 * 1000))} minutes`);
+      setTimeout(this.playRandomSound, time);
     },
     selectAll() {
       this.sounds.forEach(sound => {