Microphone sound is degraded with Internet

[bicounet18]

Hello,
With a Lenovo ideapad 330-17AST0 laptop in dual-boot Win10 and Xubuntu 18.04.1.
The internal microphone of the laptop works well with Audacity .. The Audio output works properly.
But, on the Internet (messenger, micro test with https://online-voice-recorder.com/en/)
the microphone comes out only crackling.
Browser tested: Firefox, chromium.
lspci | grep [Aa]udio

00:01.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Device 15b3
00:09.2 Audio device: Advanced Micro Devices, Inc. [AMD] Device 157a

cat /proc/asound/card0/codec* | grep Codec

Codec: Realtek Generic

cat /proc/asound/version

Advanced Linux Sound Architecture Driver Version k4.15.0-43-generic.

cat /proc/asound/cards

0 [Generic        ]: HDA-Intel - HD-Audio Generic                       HD-Audio Generic at 0xf0d64000 irq 40
1 [HDMI           ]: HDA-Intel - HDA ATI HDMI  HDA ATI HDMI at 0xf0d60000 irq 39

cat /proc/asound/pcm

00-00: Generic Analog : Generic Analog : playback 1 : capture 1
01-03: HDMI 0 : HDMI 0 : playback 1

cat /proc/asound/modules

0 snd_hda_intel
1 snd_hda_intel

Thanks for your help