Burst of sound whenever audio starts

Question

OS: Kubuntu 16.04

Whenever I pause and play I hear a loud burst of disturbance. This happens with vlc as well as youtube. I also hear the same sound when my kde finishes loading at startup. Not sure how to resolve this.

$ apt list --installed | grep pulse 
gstreamer1.0-pulseaudio/xenial-updates,now 1.8.2-1ubuntu0.1 amd64 [installed]
libcanberra-pulse/xenial,now 0.30-2.1ubuntu1 amd64 [installed,automatic]
libpulse-mainloop-glib0/xenial,now 1:8.0-0ubuntu3 amd64 [installed]
libpulse0/xenial,now 1:8.0-0ubuntu3 amd64 [installed]
libpulsedsp/xenial,now 1:8.0-0ubuntu3 amd64 [installed]
pulseaudio/xenial,now 1:8.0-0ubuntu3 amd64 [installed]
pulseaudio-equalizer/xenial,xenial,now 2.7.0.2-5~webupd8~xenial0 all [installed]
pulseaudio-module-bluetooth/xenial,now 1:8.0-0ubuntu3 amd64 [installed,automatic]
pulseaudio-module-x11/xenial,now 1:8.0-0ubuntu3 amd64 [installed]
pulseaudio-utils/xenial,now 1:8.0-0ubuntu3 amd64 [installed]

Answer 1

1. One of the cause could be pulseaudio! Personally it is haunting me so long as I am forced to use pulseaudio (I have absolute hearing, and can tell notes from hearing). Pulseaudio tries to mix the sounds on the software level (something that most of cards are able to do on hardware level, especially professional tier ones, this however could be not the case for built-in audio). The notability of all those clicks, burst of sounds depends from hardware (sound card, speakers, type of solder (Pb-Free solder worsen sound with aging as growing tin whiskers alters the powering of sound after the DAC) and perception (your ears and hearing, (You can get used to the constant same noise presented for prolonged time and loose perception of it)), and also from the levels set in global mixer and inside the software (i.e. noise will be easier heard if global mixer will be on max while application will keep minimal. The least effect of sound alteration can be achieved by using medium levels, and ~80-70% output at the software producing the sounds. On VLC you can overcome pulsaudio dequalification of sound by selecting direct sound output. On debian systems it is possible to purge pulseaudio and install alsa, however in your case with built-in audio that could give even worse sound and are not guaranteed to fix the problems. (It however helps with more professional tier sound cards, and in some rare cases built-in sound). Pulseaudio allows to output sound much louder than ALSA, and this have to be kept in mind. Crossing those limits is not without the cost of quality.

2. You should check if you have no microphone un-muted! That can produce buzz sounds.

3. If it is PC, and you have CD-ROM, there is such legacy cable (well I didn't saw this anymore) connecting CD-ROM directly to sound card, in my experience it causes hum noise.

4. Some noise can come from not well grounded/designed (motherboard) PCB of your computer. In such case the bad supply (unstable, noisy power supply) can bring the noise to the sound card (those tiny low grade built-in audio chipsets is extremely sensitive to electrical supply artifacts). You could try borrowing the power strip with emi or noise filter built-in to check if that would reduce your problem.

Answer 2

Disable loopback in alsamixer.

$ alsamixer