Create a tone, play it back and record it simultaneously

[Adazus]

Hello community,

I have been looking for a solution to the following problem for some time now:
I am not able to:

• generate a sine tone
• output it via the speakers
  and at the same time (this is the issue)
• start a recording via microphone and record the (emitted) sine tone of the oscillator.

In other words:
All ambient sounds are recorded by the microphone except the frequency generated by the oscillator reproduced by the speaker.

General question:
Is it with web-audio-api basically possible to generate a frequency, output it via the loudspeaker and record it by microphone at the same time?

On the demo from “borismus” the issue is visible:
https://borismus.github.io/spectrogram/
The tone generated by clicking on the screen (red line) is not displayed in the spectrogram.

Many thanks in advance.
Best regards
Adazus

[Adazus]

Hello together,
in the meantime, I have received help at slack.com.
The issue is that when using:
getUserMedia({audio: true})
audio-pre-processing is standardly activated.
To switch off pre-processing you can use:
getUserMedia({audio: {autoGainControl: false, echoCancellation: false, noiseSuppression: false} })
BR Adazus

[mjwilson-google]

These constraints are part of the Media Capture and Streams spec:
https://www.w3.org/TR/mediacapture-streams/#media-track-supported-constraints

The MediaStreamAudioDestinationNode definition already links to Media Capture and Streams for the definition of getUserMedia(), so I think there's not any spec work necessary regarding this.

I'm glad that you got help on Slack, and thanks for posting the solution. I will move this issue to the discussion board, so that it can potentially help others with the same problem.