So I'm playing around with the voice lines for the announcer with ambient_generics. In my map, I used the lines:
"At the time of this recording, Federal disclosure policies require us to inform you that this next test is probably lethal and to redirect you to a safer test environment. We will attempt to comply with these now non-existent agencies by playing some more smooth jazz."

but it doesn't actually play the smooth jazz, so I was trying to figure out if there was a way to just play the end part of "This next test is very dangerous. To help you remain tranquil in the face of almost certain death, smooth jazz will be deployed in three. Two. One. [SMOOTH JAZZ]" where he says smooth jazz will be deployed. I tried fiddling with volume outputs, but that didn't work. Any Suggestions?

Edit: fuck it, I misread your post entirely.

Play the first ambient_generic. Then fiddle around with the timing: Have the second sound start playing with 0 Volume and raise the volume the moment the Jazz starts to play.

Edit2: You say you already tried that. I should stfu.

I'd go with timing for this.

Set the volume of the smooth jazz quote to 0 and start playing it X seconds (or how many seconds depending on the previous quote) after your quote so that the Smooth Jazz quote has some time to play before the Smooth Jazz part.
Set the volume to 10 right before it starts the smooth jazz. This would take some time since you have to time the quotes.

Or, you could just edit the Smooth Jazz out and add it in as a separate wav file.

Habzs wrote:
Or, you could just edit the Smooth Jazz out and add it in as a separate wav file.

Much easier, and it can loop.

Also, you should be using logic_choreographed_scenes instead of ambient_generics for anything said by GLaDOS or the Announcer. Use an ambient_generic looping for the smooth jazz, then just stop it after a certain amount of time.

So I downloaded GCFScape, extracted the sound, and edited it. Thx

The game files are located in the portal 2 folder (Steam\steamapps\common\portal 2\portal2) inside several packages. To open them you need gcfscape (download). To view the files, open "pak01_dir.vpk" and go to sound/vo/announcer to find the announcer voice lines. You can save any file by right click->extract.

I sincerely think the easiest way to go with this is to grab the sound file (as soptipp1 said all of them ae into the pak01_dir.vpk files you've got into each of the 3 main folders of the game: portal2/portal2, portal2/portal2_dlc1 and portal2_dlc2), edit it with some Audio program (erasing the words you don't want) and play it as a custom sound.

If you don't knw how to do it, just post the file and I'll do it in an instant for you.