Hello!
I bought a microphone (MICO from Trust) and plugged it into the 3.5 jack
of my computer.
My OS is Debian testing on an old Acer desktop.
To begin, I had a lot of static noise which was removed when I tried:
pactl load-module module-echo-cancel aec_method=webrtc
without really understanding what I did.
I have looked into pactl list and see this:
Source #2
State: RUNNING
Name: alsa_input.pci-0000_00_14.2.analog-stereo
Description: Built-in Audio Analog Stereo
Driver: module-alsa-card.c
Sample Specification: s16le 2ch 48000Hz
Channel Map: front-left,front-right
Owner Module: 8
Mute: no
Volume: front-left: 21845 / 33% / -28.63 dB, front-right:
21845 / 33% / -28.63 dB
balance 0.00
Base Volume: 5841 / 9% / -63.00 dB
Monitor of Sink: n/a
Latency: 2301 usec, configured 66666 usec
Flags: HARDWARE HW_MUTE_CTRL HW_VOLUME_CTRL DECIBEL_VOLUME LATENCY
Properties:
alsa.resolution_bits = "16"
device.api = "alsa"
device.class = "sound"
alsa.class = "generic"
alsa.subclass = "generic-mix"
alsa.name = "ALC662 rev1 Analog"
alsa.id = "ALC662 rev1 Analog"
alsa.subdevice = "0"
alsa.subdevice_name = "subdevice #0"
alsa.device = "0"
alsa.card = "1"
alsa.card_name = "HDA ATI SB"
alsa.long_card_name = "HDA ATI SB at 0xfeb40000 irq 16"
alsa.driver_name = "snd_hda_intel"
device.bus_path = "pci-0000:00:14.2"
sysfs.path = "/devices/pci0000:00/0000:00:14.2/sound/card1"
device.bus = "pci"
device.vendor.id = "1002"
device.vendor.name = "Advanced Micro Devices, Inc.
[AMD/ATI]"
device.product.id = "4383"
device.product.name = "SBx00 Azalia (Intel HDA)"
device.form_factor = "internal"
device.string = "front:1"
device.buffering.buffer_size = "384000"
device.buffering.fragment_size = "192000"
device.access_mode = "mmap+timer"
device.profile.name = "analog-stereo"
device.profile.description = "Analog Stereo"
device.description = "Built-in Audio Analog Stereo"
alsa.mixer_name = "Realtek ALC662 rev1"
alsa.components = "HDA:10ec0662,10258100,00100101"
module-udev-detect.discovered = "1"
device.icon_name = "audio-card-pci"
Ports:
analog-input-front-mic: Front Microphone (priority:
8500, not available)
analog-input-rear-mic: Rear Microphone (priority: 8200,
available)
analog-input-linein: Line In (priority: 8100, not available)
Active Port: analog-input-rear-mic
Formats:
pcm
Source #7
State: RUNNING
Name: alsa_input.pci-0000_00_14.2.analog-stereo.echo-cancel
Description: Built-in Audio Analog Stereo (echo cancelled with
Built-in Audio Analog Stereo)
Driver: module-echo-cancel.c
Sample Specification: float32le 1ch 32000Hz
Channel Map: mono
Owner Module: 31
Mute: no
Volume: mono: 21845 / 33%
balance 0.00
Base Volume: 65536 / 100%
Monitor of Sink: n/a
Latency: 9221 usec, configured 66666 usec
Flags: HW_MUTE_CTRL LATENCY
Properties:
device.master_device =
"alsa_input.pci-0000_00_14.2.analog-stereo"
device.class = "filter"
device.intended_roles = "phone"
device.description = "Built-in Audio Analog Stereo (echo
cancelled with Built-in Audio Analog Stereo)"
device.icon_name = "audio-input-microphone"
Formats:
pcm
Now I wonder why there is a difference in sample specification between
the sources.
Without echo cancellation:
Sample Specification: s16le 2ch 48000Hz
With echo cancellation:
Sample Specification: float32le 1ch 32000Hz
Regards,
Per Gunnarsson
