Cannot record silence

[Robert2]

What I tried to say is that WASAPI (Audacity) does record audio stream when there is none coming from the audio source (when the Web radio stream is paused). In such a case, WASAPI (Audacity) does count sheep when there are no sheep in the Web page pen: it records silence.
It also records silence before the Web radio stream is unpaused if there has been a previous recording, and it has been undone (Edit > Undo).

[steve]

when there is none coming from the audio source (when the Web radio stream is paused).

As long as the audio stream is running, Audacity can record it, even if it's a stream of zeros (absolute silence). When there is no audio stream (not even zeros), then there's nothing to record and Audacity will wait (after exhausting buffered data) for the next audio sample.

[steve]

Go into the Windows Sound settings and select the recording device that you are using. For that device, enable the option "Listen to this device".

This is an easy way to ensure there is always an active audio stream.

[Robert2]

OK. Understood.
But “Listen to this (recording) device” is of no use with WASAPI because WASAPI has no real recording device: it uses the Speakers or the Headset in a loopback.
As far as my system is concerned, I could never make MME or DirectSound work to record streaming audio.
WASAPI works flawlessly.
Now I just tried this:
I started an audio stream in a tab in Firefox. I paused it. I was able to record silence in Audacity.
I kept the first audio stream paused in the first tab, but I started a different audio stream in a second tab still in Firefox. Audacity started recording the new audio stream and ignored the silence coming from the stream paused in the first tab.
So it is possible to record silence and actual sound alternately switching from one audio stream to the other.

[steve]

When using WASAPI loopback, if "any" device is being listened to, there should be an active audio stream. To avoid noise in the recording, turn down the recording level of that device.

[Robert2]

Both my Speakers and Headset are being “listened to” in the Windows Sound panel. This is permanent. I use the Sound icon in the Notification Area to switch from Speakers to Headset and back at will.
I don’t see how it is possible to “turn down the recording level” of the Speakers or Headset in Audacity. The WASAPI recording level seems to be self-adjusting and is not linked to the actual listening level in the Speakers.
Anyway, I can record silence by pausing an audio stream, and go on recording an unpaused different audio stream if I switch to a different tab and audio source.
This was the OP’s aim.

[DalePickles]

Maybe I'm going daffy (quite possible) but it seems that until a week ago or so I could simply (1) Boot up my PC, then (2) launch Audacity, then (3) click the red Record button, and Audacity would record silence until I clicked the stop button.

And starting a week ago, Number (3) above does nothing until I start pushing sound out my speakers from whatever app or website.

So tonight I figured out a work-around based on a few suggestions in this thread... I found a "video" on YouTube that does a silent countdown from 8 hours to zero (https://www.youtube.com/watch?v=OvRe01ya_io). As long as that YouTube video is running, Audacity behaves for me like it used to behave.

Thanks to all who responded. I'm still a bit confused, but case closed!!

D. P.

[revysama]

It happened to me as well , recently i had to do a scan for hardware changes and since then i could not record silence , but i accidentally found a workaroud , if you get into a discord call by yourself audacity will record the silence that is picking up from the discord call .