alsa + ReSpeaker 4-Mic Linear Array Kit for Raspberry Pi + ec

[blademckain]

Hello,
I have an echo cancellation problem in a raspberry application that works using the alsa default channel.
Would it be possible to set ec + ReSpeaker 4-Mic Linear Array Kit for Raspberry Pi as the default alsa channel (so that it can be used by my application)?
I would like it to work on a raspberry Pi zero W, do you think it can support it?

[xiongyihui]

It works with Pi zero W. You can modify /etc/asound.conf and ~/.asoundrc to configure ALSA default channel. Check https://alsa-project.org/wiki/Asoundrc

[blademckain]

Hi,
i have installed the ReSpeaker 4-Mic Linear Array following this guide
http://wiki.seeedstudio.com/ReSpeaker_4-Mic_Linear_Array_Kit_for_Raspberry_Pi/

now my default alsa device is the ReSpeaker 4-Mic Linear Array

i have installed ec

if i execute
./ec_hw -i plughw:1 -c 8 -l 7 -m 0,1,2,3

i get:

warning: The echo canceller started acting funny and got slapped (reset). It swears it will behave now. warning: The echo canceller started acting funny and got slapped (reset). It swears it will behave now. warning: The echo canceller started acting funny and got slapped (reset). It swears it will behave now. warning: The echo canceller started acting funny and got slapped (reset). It swears it will behave now.
seems, that ./ec_hw -i plughw:1 -c 8 -l 7 -m 0,1,2,3 is not the correct command for the 4mic linear array

1. what is the correct command for the 4 mic linear array?
2. ec_hw is to be started manually every time?
3. how can I make that the default capture device ( ALSA ) use the EC (ec_hw)?

`
root@raspberrypi:/tmp# arecord -L
null
Discard all samples (playback) or generate zero samples (capture)
jack
JACK Audio Connection Kit
pulse
PulseAudio Sound Server
default
ac108
dmixer
ac101
eco
usbstream:CARD=ALSA
bcm2835 ALSA
USB Stream Output
sysdefault:CARD=seeed8micvoicec
seeed-8mic-voicecard,
Default Audio Device
dmix:CARD=seeed8micvoicec,DEV=0
seeed-8mic-voicecard,
Direct sample mixing device
dsnoop:CARD=seeed8micvoicec,DEV=0
seeed-8mic-voicecard,
Direct sample snooping device
hw:CARD=seeed8micvoicec,DEV=0
seeed-8mic-voicecard,
Direct hardware device without any conversions
plughw:CARD=seeed8micvoicec,DEV=0
seeed-8mic-voicecard,
Hardware device with all software conversions
usbstream:CARD=seeed8micvoicec
seeed-8mic-voicecard
USB Stream Output

root@raspberrypi:/tmp# aplay -L
null
Discard all samples (playback) or generate zero samples (capture)
jack
JACK Audio Connection Kit
pulse
PulseAudio Sound Server
default
ac108
dmixer
ac101
eco
sysdefault:CARD=ALSA
bcm2835 ALSA, bcm2835 ALSA
Default Audio Device
dmix:CARD=ALSA,DEV=0
bcm2835 ALSA, bcm2835 ALSA
Direct sample mixing device
dmix:CARD=ALSA,DEV=1
bcm2835 ALSA, bcm2835 IEC958/HDMI
Direct sample mixing device
dsnoop:CARD=ALSA,DEV=0
bcm2835 ALSA, bcm2835 ALSA
Direct sample snooping device
dsnoop:CARD=ALSA,DEV=1
bcm2835 ALSA, bcm2835 IEC958/HDMI
Direct sample snooping device
hw:CARD=ALSA,DEV=0
bcm2835 ALSA, bcm2835 ALSA
Direct hardware device without any conversions
hw:CARD=ALSA,DEV=1
bcm2835 ALSA, bcm2835 IEC958/HDMI
Direct hardware device without any conversions
plughw:CARD=ALSA,DEV=0
bcm2835 ALSA, bcm2835 ALSA
Hardware device with all software conversions
plughw:CARD=ALSA,DEV=1
bcm2835 ALSA, bcm2835 IEC958/HDMI
Hardware device with all software conversions
usbstream:CARD=ALSA
bcm2835 ALSA
USB Stream Output
sysdefault:CARD=seeed8micvoicec
seeed-8mic-voicecard,
Default Audio Device
dmix:CARD=seeed8micvoicec,DEV=0
seeed-8mic-voicecard,
Direct sample mixing device
dsnoop:CARD=seeed8micvoicec,DEV=0
seeed-8mic-voicecard,
Direct sample snooping device
hw:CARD=seeed8micvoicec,DEV=0
seeed-8mic-voicecard,
Direct hardware device without any conversions
plughw:CARD=seeed8micvoicec,DEV=0
seeed-8mic-voicecard,
Hardware device with all software conversions
usbstream:CARD=seeed8micvoicec
seeed-8mic-voicecard
USB Stream Output
root@raspberrypi:/tmp#
`

[blademckain]

help!

[xiongyihui]

It seems that your sound number is 0 (CARD=seeed8micvoicec,DEV=0).

./ec_hw -i plughw:seeed8micvoicec -c 8 -l 7 -m 0,1,2,3

To run ec_hw automatically, you should write a systemd service.

With asound.conf. the output of ec_hw will be set as the default capturing device.

[blademckain]

Thx u, i try!
Can u put in your repo a systemd service for Raspbian?

[blademckain]

with your asound.conf I can't play audio
Is it possible to use ec_hw and simultaneously play audio?