xCore Array Microphone Poor Audio Quality

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xCore Array Microphone Poor Audio Quality

Postby snowdog » Sat Jun 15, 2019 3:12 pm

Are there any known issues with this hardware? So far I've been really disappointed. I tried just using the default application, applying some gain, and listening to the output. The noise floor is a lot higher than I would have expected for these microphones, but that aside I hear drifting low frequency tonal sounds (sort of like RF interference) you might expect when trying to tune in to a radio station.

For what I paid for this I'm extremely underwhelmed. Is the audio recording quality of these PDM microphones supposed to be this poor? Are any other users able to chime in with their experience? I'm at a complete loss here. Even when there is some background noise source it doesn't mask it. Something *must* be going wrong here. I'm out hundreds of dollars and many hours of development time..
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Postby mon2 » Sat Jun 15, 2019 4:54 pm

Hi snowdog. Not an audio developer nor have the referenced kit here but...know that XMOS has a key focus on the audio market and considered the industry leader for high end audio. They have a heavy investment of time and finances from assorted outside investors into this technology so suspecting it is something logical that is resulting in the poor results.

1) check the details of the firmware for your specific kit. Which version of the firmware is currently flashed on your kit? The purchased kit may be using an older IP.

2) Which kit do you own exactly?

3) Can you visualize the audio capture with a tool like Audacity?

4) From a past review, believe that the microphones are high end SMD microphones from Akustica and/or Infineon. Believe that Akustica is no longer so Infineon will be the better choice moving forward.

Review these:


There are many users of the same tools so hope someone else will chime in to assist or at least share their feedback.

You can also review some of the postings and test methods about the XMOS CPU based microphone array from SEEED:


On the above landing page from SEEED (why so many Es!!!) - is your audio quality from your microphone array matching that is posted from this manufacturer in Shenzhen?

Please post your updates.

One more thing...we have the ReSpeaker by SEEEED (added one more E for the fun of it...) but is in the lab at work. Let us know if you would like for us to test anything on this PCB.

This will have to be at the earliest on our Monday...
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Postby snowdog » Sat Jun 15, 2019 8:48 pm

Thanks. Maybe I'll post some further details this weekend. I wanted to put it out there to see if anybody else has experienced these problems.. This is the latest hardware, infineon microphones (69 dB SNR). It's seems like the reference design is also susceptible to simply moving it around while recording as I hear really weird audio artifacts. I was expecting a lot more. I get better audio out of much lower end offerings right now.

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