XCore microphone array questions (XK-USB-MIC-UF216)

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bryant
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Joined: Wed Apr 13, 2016 5:51 pm

XCore microphone array questions (XK-USB-MIC-UF216)

Post by bryant »

Does the app_usb_aud_mic_array application sample at 48 KHz? I've built the app and loaded it to the XMOS mic array but one of the audio engineers here is telling me that the recorded 7 channel audio file contains only 4KHz audio data and not 48 KHz as expected. Where can I verify that the app_usb_aud_mic_array application is setting everything up for 48 KHz?

Thanks in advance for your help.

Bryant


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andrew
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Post by andrew »

Does the app_usb_aud_mic_array application sample at 48 KHz?

Yes, it can do. It supports 48k, 24k, 16k, 12k and 8kHz (I'm not sure they can all be selected from USB). I have just tested app_usb_aud_mic_array_2i8o2.xe and can confirm content above 4kHz.

I've built the app

Which app specifically?

and loaded it to the XMOS mic array but one of the audio engineers here is telling me that the recorded 7 channel audio file contains only 4KHz audio data and not 48 KHz as expected. Where can I verify that the app_usb_aud_mic_array application is setting everything up for 48 KHz?

What OS are you using? Also UAC 1.0 or 2.0? Thanks
bryant
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Post by bryant »

Andrew,

Thanks for the quick response. I tried making some recordings of my own and the only problem that I see is that the mic array firmware only supports sample rates up to 44.1 and not 48 KHz. It looks like the board+firmware can indeed capture audio past 4k. There was an user error somewhere on our end.

To answer your questions:

The application binary is bin/1i8o2/app_usb_aud_mic_array_1i8o2.xe.

I plug the mic array into a MacBook Pro running OS X El Capitan version 10.11.6. The following shows up in the System Information / USB tree:

USB 3.0 Bus:

Capacity: 21.1 MB (21,135,072 bytes)
Removable Media: Yes
BSD Name: disk3
Host Controller Driver: AppleUSBXHCIPPT
Partition Map Type: Unknown
PCI Device ID: 0x1e31
PCI Revision ID: 0x0004
PCI Vendor ID: 0x8086

USB3.0 Hub :

Product ID: 0x0812
Vendor ID: 0x2109 (VIA Labs, Inc.)
Version: b.e1
Speed: Up to 5 Gb/sec
Manufacturer: VIA Labs, Inc.
Location ID: 0x14300000 / 3
Current Available (mA): 1800
Current Required (mA): 0
Extra Operating Current (mA): 0
Capacity: 3 TB (3,000,592,981,504 bytes)
Removable Media: Yes
Detachable Drive: Yes
BSD Name: disk2
Partition Map Type: GPT (GUID Partition Table)
Volumes:

XMOS Microphone Array UAC2.0:

Product ID: 0x0009
Vendor ID: 0x20b1
Version: 6.f2
Speed: Up to 12 Mb/sec
Manufacturer: XMOS
Location ID: 0x14200000 / 11
Current Available (mA): 1000
Current Required (mA): 500
Extra Operating Current (mA): 0

When I open the XMOS Microphone Array UAC1.0 settings in the Mac Audio MIDI Setup application, the app shows that the device supports 8 channels of 16bit Integer samples at rates of 8000.0, 11025.0, 12000.0, 16000.0, 32000.0, and 44100.0 Hz. There isn't a 48000.0 option.

I use Audacity to make recordings. The board shows up as XMOS Microphone Array UAC1.0 in Audacity. I selected 44100 Hz for recording and then recorded a log sine sweep from 100 Hz to 24000 Hz. Looking at the spectrogram, it appears that the energy rolls off around 20k which I totally expect.

I attached the spectrogram.
sine_sweep.jpg
Screen shot showing spectrogram.
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sine_sweep.jpg
Screen shot showing spectrogram.
(125.23 KiB) Not downloaded yet
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andrew
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Post by andrew »

I would recommend you use UAC 2.0 which should be the build called
bin/2i8o2/app_usb_aud_mic_array_2i8o2.xe
The bandwidth of UAC 1.0 might be the factor that is limiting you with 8 in and 2 out.

That was the binary I tried and I had no problems.
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andrew
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Post by andrew »

in customdefines.h:

*/ Maximum frequency in full-speed mode /*
#ifndef MAX_FREQ_FS
#define MAX_FREQ_FS (44100) / FS can't handle 8in2out at 48000 /
#endif
puzzle
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Post by puzzle »

Hi Andrew, Bryant. I'm working on XK-USB-MIC-UF216 loading app_usb_aud_mic_array 2i8o2 without any change to the project. But when plug in, it can not be recognized by Mac 10.11.5. Also notice some posts saying the same issue. It's great to see you have it running successfully, do you know if any specific action needed?
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Ross
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Location: Bristol, UK

Post by Ross »

Firmware version 6.19+ must be used.
niruyadla@gmail.com
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Post by niruyadla@gmail.com »

Download "sw_usb_audio-[sw]_6.15.2rc1.zip" from the below link
http://www.xmos.com/support/software/uac2

And replace module_xud with the below one
https://drive.google.com/drive/folders/ ... sp=sharing

Then generate "app_usb_aud_mic_array_2i8o2.xe" firmware file with the above combination using xtimecomposer

Now you must be able to find XMOS USB 2.0 audio device on your windows PC.

Note: Makesure you have installed windows driver from the below link (TUSBAudio control panel)
http://www.xmos.com/support/usb-audio-driver-support
niruyadla@gmail.com
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Post by niruyadla@gmail.com »

As well find xe firmware files here
https://drive.google.com/drive/u/0/fold ... TdLbGdxbmM
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