 <p>The first thing to understand is why it keeps playing forever rather than just 0.2. You can see what's going on if you run the <code>Pbind</code> equivalent:</p> <pre><code> p = Pbind(\instrument, \default, \dur, 0.2, \freq, 400).play; </code></pre> <p>If you run this you don't just hear a single note, you hear the note being hit again and again forever, until you run</p> <pre><code> p.stop; </code></pre> <p>So why is that? It's because all of the "values" specified are simple numbers or symbols (<code>\default ... 0.2 ... 400</code>), and these are always interpreted as meaning "continue forever or until something else stops us".</p> <p>If you wanted Pbind to play just one note you would need to use at least one pattern in there which limits itself to just one item:</p> <pre><code> p = Pbind(\instrument, \default, \dur, 0.2, \freq, Pseq([400], 1)).play; </code></pre> <p>So you can do the same thing with Pmono:</p> <pre><code> p = Pmono(\default, \dur, 0.2, \freq, Pseq([400], 1)).play; </code></pre> <p>This has <em>exactly the same result</em> as the Pbind example, actually, but that's because it's playing only one note. We can make the difference a little bit clearer with these two-note examples:</p> <pre><code> p = Pbind(\instrument, \default, \dur, 0.4, \freq, Pseq([400, 500], 1)).play; p = Pmono(\default, \dur, 0.4, \freq, Pseq([400, 500], 1)).play; </code></pre> <p>The first plays two separate notes, the second plays one with a pitch change halfway through.</p> <p>So, note that your inference was correct - the node does get deleted after the Pmono terminates - but your Pmono was not terminating.</p>