Sound Sensor With A Capacitor - Question

About a year ago, Steve G asked about sound sensors.
https://synthiam.com/Community/Questions/7481

DJ said to add a capacitor to the signal line...

Quote:

those sensors (analog or digital) will work fine - IF you add a capacitor to the signal line. This is because the audio is either ON or OFF real quick with no "hold". This means unless you're sampling at the exact moment of audio, you will miss it. As what you are experiencing...So throwing a capacitor to keep the voltage higher longer will help.

so my question is, do you add the capacitor only on the signal line? Or one end of the capacitor on signal and one end to negative? confused

Thanks in advance.