Multiple Mic Auto-Mixer

[phil]

I am looking for a audio processor that will provide 8 channel automatic mixing. That is, when someone is speaking at a certain threshold on a given mic, the other mics are muted or gain is significantly reduced.

[Peter BENSCH]

Depending on the audio requirements (frequency range/bandwidth), you could do that using the support of the hardware peripheral DFSDM (Digital filter for Sigma-Delta Modulators) which has been introduced some years ago with the family of STM32L4 microcontrollers. DFSDM can be used for both analog Sigma Delta front ends and up to 8 stereo or 16 mono digital MEMS microphone channels.

You can find some training materials for the STM32 families that provide this DFSDM at the following URLs. Please search there for DFSDM:

• STM32L4 (Ultra Low Power family)
• STM32L4+ (Ultra Low Power family)
• STM32F7 (Hig Performance family)
• STM32H7 (Very High Performance family)

ST also offers a range of digital MEMS microphones that can be used for this kind of applications, e.g. the MP34DT06J.

In addition to the STM32CubeIDE, the FP-AUD-SMARTMIC1 software package could be a good starting point for software development.

Good luck!

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/Peter

[Ozone]

> You can find some training materials for the STM32 families that provide this DFSDM at the following URLs. Please search there for DFSDM: ...

Not sure if the capabilities of the mentioned DFSDM unit in the listed MCUs matched the channel requirement of the O.P.

The same goes for MEMS microphones, which imply an I2S interface.

An analogue interface (via the inbuilt SAR-ADC) would be an option most F3, F4 or F7 MCUs could relatively easy fill.

Especially for a device directed at human speech, rather than HiFi audio.