What it said on the tin. Absolutely no auditory feedback is quite odd.

You mean the laser rifle and laser sniper rifle firing?
I copied from the vanilla laser turret firing, so acting just the same with minor damage tuning. Same graphics and sound (if any).
Yes, I feel weird that laser turrets are soundless. In fact someone has already reported this in some early versions of 0.17, but the devs decided it was not a bug and did no changes to it.
If main game decided to add sound effects to laser turrets, I will do that to my laser rifles too. (I prefer to stick to vanilla laser turret here, and I do not have any good "continuous" SFX to be used here anyway.)

I just confirmed the vanilla laser turrets are soundless, both in 0.17 and 0.18. BTW, 0.18 added a lot of biter screaming, but still no laser firing sound.

well, alright then.

Some findings about the laser sound.
In Debug settings (F5), one can find three entries about "sound". Just check them all.
Then fire up the laser turret or laser rifle or laser sniper rifle.
Debug text at lower left corner shows SFX __base__/sound/fight/electric-beam.ogg is actually played, so actually DO have sound, in theory.
But at least to my ears, I cannot hear anything different.
The main problem actually lies in the SFX file (where you can dig it out in your game data folder)... Just put it to WinAmp or any music player (modern players should support OGG files). See if you can hear any distinguishable sound?

To solve this problem, it means needing a replacement of this SFX file.
The best way would be the Wube devs use a new SFX, which in theory my mod should automatically support it.
(Most SFX are licensed. And "continuous" laser firing SFX is even much more rare to be found.)

New from 0.18.7+.
Wube devs have made a new laser sound now, and it is audible.
So I consider this case fixed now.

great