ReSpeaker 4-Mic Linear Array

info about ReSpeaker series products

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dragon38
Pre-kindergarten
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Joined: Mon May 27, 2019 4:15 pm

ReSpeaker 4-Mic Linear Array

Post by dragon38 » Mon May 27, 2019 4:21 pm

Hello,
my team would like to create a smart intercom using raspberry.
I wanted to ask you if the product ReSpeaker 4-Mic Linear Array can:
1) be used with alsa drivers, as a default device
2) has already integrated the echo cancellation
3) the "JST 2.0 speaker jack" output is amplified
4) Which speaker is more correct to use in the output "JST 2.0 speaker jack", an 8 Ohm or a 50 Ohm?

bill.yu
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Joined: Mon Apr 02, 2018 11:05 am

Re: ReSpeaker 4-Mic Linear Array

Post by bill.yu » Wed Jun 05, 2019 5:19 pm

Hi there

please see below replies.

1) be used with alsa drivers, as a default device: Yes

2) has already integrated the echo cancellation: there are 2 playback channels, one is from jst2.0 and other is from 3.5mm audio port. you can refer to https://github.com/voice-engine/ec for AEC.

3) the "JST 2.0 speaker jack" output is amplified: yes, the amplifer is tpa6205a, you can refer to datasheet. http://www.ti.com/lit/ds/symlink/tpa6205a1.pdf

4) Which speaker is more correct to use in the output "JST 2.0 speaker jack", an 8 Ohm or a 50 Ohm? 8ohm.

thanks.

dragon38
Pre-kindergarten
Pre-kindergarten
Posts: 5
Joined: Mon May 27, 2019 4:15 pm

Re: ReSpeaker 4-Mic Linear Array

Post by dragon38 » Tue Jul 30, 2019 6:24 pm

Hello,
I installed a ReSpeaker 4-Mic Linear Array on top of a Raspberry pi zero

I followed these installation steps

Code: Select all

sudo apt-get update
sudo apt-get upgrade
git clone https://github.com/respeaker/seeed-voicecard.git
cd seeed-voicecard
sudo ./install.sh 
sudo reboot
Now i have

Code: Select all

root@raspberrypi:~# 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
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

Code: Select all

root@raspberrypi:~# 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
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
In my application i can set the device to use:

Code: Select all

SND_CAPTURE='ALSA: USB PnP Sound Device'
SND_PLAYBACK='ALSA: USB PnP Sound Device'
What should I write to make my application use the ReSpeaker? ALSA: ???

dragon38
Pre-kindergarten
Pre-kindergarten
Posts: 5
Joined: Mon May 27, 2019 4:15 pm

Re: ReSpeaker 4-Mic Linear Array

Post by dragon38 » Wed Jul 31, 2019 5:28 pm

Ok, work with

Code: Select all

SND_CAPTURE='ALSA: default device'
SND_PLAYBACK='ALSA: default device'
I am using the jst2.0 with speaker as output

Now the next step,
activate the EC
i follow this guide

Code: Select all

sudo apt-get -y install libasound2-dev libspeexdsp-dev
git clone https://github.com/voice-engine/ec.git
cd ec
make
if i execute

Code: Select all

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

Code: Select all

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

dragon38
Pre-kindergarten
Pre-kindergarten
Posts: 5
Joined: Mon May 27, 2019 4:15 pm

Re: ReSpeaker 4-Mic Linear Array

Post by dragon38 » Fri Aug 09, 2019 2:34 pm

isn't there any support to help me?

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