Active Noise Cancellation

Hello Hannes,

You might want to try to search the forum. Here is a post that has a lot of great information.

(+) Help with Modified FxLMS/FxNLMS in an ANC application - Q&A - SigmaDSP Processors and SigmaStudio Development Tool - EngineerZone (analog.com)

Using the ADAU1452 or the ADAU1467 family of processors eval boards may be a good choice for you. The ADAU1467 eval board may be the most flexible for you.

Dave T

Thank you Dave!

Hey Dave, one follow-up question.

What is the maximum number of speakers i can drive with the ADAU1452 or the ADAU1467 eval board?

Hi hannes0711,

If you are using an ADAU1452 or ADAU1467 Eval boards then you can drive up to 8 outputs as there are eight DAC's in the CODEC. If you want more than that then you have to connect some external codecs with high DAC outputs or something.

Regards,

Harish

Hello hannes0711,

To add to what Harish has explained.

If you want to use external codecs, then the ADAU1452 can send out 48 channels if you use the serial ports to their maximum capability. There are four serial output ports so two will have to be using TDM16 and two have to be using TDM8 to output 48 total channels.

The built in codec on the eval board would have to be changed to be controlled either from the DSP or from SigmaStudio. Then you would have to do some rewiring on the eval board because you have to use the first serial port on the codec and that is connected to the first serial output port of the ADAU1452. That is one of the serial ports that can do TDM 16 so you will use up one 16 capable port for only 8 channels.

Basically, what I am saying is that you would have to use all external DACs and keep the jumper wires short. There will be some technical challenges.

The easiest would be to use TDM8 on all serial ports so that would give you 32 channels of outputs.

These serial data streams will have to go to multichannel DACs like the ADAU1966A

It will require some wiring work.

Dave T

Thank you Harish and Dave for your responses!

Another question:

Is it possible to connect several reference microphones and error microphones to the ADAU, which control individual loudspeakers? Or is only one reference and one error microphone possible, which then control all speakers at once?

If so, how many reference mics and error mics can I connect to the ADAU1452 or the ADAU1467 eval board?

Hannes

Hello Hannes,

You didn't say what kind of mic which you are gonna use. If it's a PDM mic then you can connect up to four. If it's i2s then it's gonna be more. Besides the input and output that you are connecting physically, It's all about the processing that you do with the algorithm. In the context of ANC we don't have an algorithm that supports more that eight of each(ref, error ,output).

So please gives us the info about what kind of mics, how many loudspeakers and mics that you wanna use. So that we can try to give a clear picture.

Regards,

Harish

Hey Harish, thanks again for your answer!

I'm planning to use the Visaton BF-45 as loudspeakers and the CMA-4544PF-W as a microphone.

Or do you have any suggestions for a microphone or loudspeaker, which suits better to one of your EVAL-boards?

Greetings,

Hannes

Hello Hannes,

In the perspective of the Eval board which you are using, You can connect up to 4 analog mics as we have 4 ADC's and 8 speaker outputs as we have 8 DAC's in the Eval board which has AD193x CODEC in it. For the above mentioned mics and speakers, You will obviously need a pre-amp and power-amp respectively. The Eval board is designed for line level input. You need some gain to make it as a line level signal from a mic level signal. And a power amp for the speakers.

Regards,

Harish

Hello,

For the loudspeaker amps, you could consider the MAX98357. If you need more than 3W per channel there are other devices in the MAX98xxx family. You can connect 8 of them to a TDM8 serial port. Below is a link to the info, and a photo of an 8 channel setup using a ADAU1452 eval board.

Overview | Adafruit MAX98357 I2S Class-D Mono Amp | Adafruit Learning System