Where do I put the Classic Voices files?

Copy the extracted Published folder into Documents\My Games\Killing Floor 2. Some players report it also works when the files go into the KFGame folder inside the game's install directory.

Which characters does the mod affect?

Community reports say it only affects the Classic Masterson and Classic Briar characters, so you will hear the old voices when those characters are in your team.

Is the audio quality the same as the original game?

No, the guide describes the voice-overs as slightly lower quality than the KF2 ones, but far more memorable.

Mods & Workshop

KF2 Classic Voices Mod: Killing Floor 1 Voice-Overs in KF2

The Classic Voices mod brings the voice-overs of Killing Floor 1 into Killing Floor 2. The guide describes them as slightly lower in quality than the KF2 voice lines but far more memorable, which is why many players install them. The installation is a simple three-part process.

Download the mod

Download the Classic Voices.zip archive from the author's file host link in the original guide.

Put the folder where it belongs

Extract the ZIP with any archive program until you have the Published folder.
Copy that Published folder into Documents\My Games\Killing Floor 2.

That is all. After that the classic KF1 voices play in the game.

Community notes

These points come from reader comments on the original guide:

As of 2021 players reported it still worked fine; one noted the files can also go into the KFGame folder inside steamapps\common\killingfloor2.
The mod seems to apply to the Classic Masterson and Classic Briar character versions. With the default characters you will not hear the change, and you hear the old voices only when those classic characters are in your team.
If something does not work, check that the Published folder is in the right place and that you are using one of the classic characters.

FAQ

Where do I put the Classic Voices files?: Copy the extracted Published folder into Documents\My Games\Killing Floor 2. Some players report it also works when the files go into the KFGame folder inside the game's install directory.
Which characters does the mod affect?: Community reports say it only affects the Classic Masterson and Classic Briar characters, so you will hear the old voices when those characters are in your team.
Is the audio quality the same as the original game?: No, the guide describes the voice-overs as slightly lower quality than the KF2 ones, but far more memorable.