Our customer xxx doesn’t understand why the AD1974 is not necessary ( as you suggested in your first answer) … they planed to use it in the way that they had already explained:
“Our customer xxxx ( specialist in Megaphones ) is thinking about using SigmaDSP ADAU1702 or ADAU1701 for 31 band equalization over 2 audio channels as is shown in the attached image file.
The equalizer must be able to be updated on the fly using an external MCU.
In addition, the customer needs to control the Loudspeaker`s line status ( that will be different from a given building installation to others ) and they plan to inject a "pure tone" signal doing a scanner in different frequencies and measuring voltage & current at the output of each power amplifer using the AD1974.
For doing the measure, they plan to use your AD1974 connected to the DSP using a TDM bus ( or I2C) . Once the audio signals where already inside of the Sigma DSP, would be treated to fit the Power and Impedance of each particular building installation.
The DSP & AD1974 control could be done using an SPI connected to the external MCU that would take care of "on the fly" DSP parameter variation and AD1974 initialization besides of reporting the equalization status adopted by the DSP.
All this explanation has been drawn in the attached schematic.”
Could you please explain us why do you think that AD1974 is not necessary of if you see a better way to do the same functionality ?
Best regards, Ignacio