I don’t have any idea how to call this, so I’ll just explain what I need.
Watch a bit of this video, after the 15:43 mark:
http://youtu.be/ISMtvNMFxFU?t=15m43s
Notice how the gun sound when in the vacuum of space? Well I have a bunch of sci-fy laser and engine sound and I want to make them sound just like that. As if you are in a spaceship cockpit in space.
Hope this is clear enough.
Thanks.
I know somebody is going to give you the lecture that there is no sound in a vacuum. Hollywood has been struggling with this for years.
I would start with a muffling filter (washcloth over your mouth) and add echo or decaying repeat. I’ve had sound like that when somebody drops a load of lumber in a very large unfinished room. Multiple decaying echoes come back after the initial shock.
You can get the muffling with Effect > Equalize, or Effect > Low Pass Filter.
Attached Gun Echo and how I did it. Click on the picture.
It’s based on Generate > Click Track so you can hear what the original sounded like.
I applied Effect > Low Pass Filter of about 400Hz. Then Effect > Amplify to -3 to make up the difference in volume caused by the Low Pass.
Then I duplicated the track twice (giving me four tracks). Tracks two, three and four are reduced in volume with the sliders on the left (more as you go down), and each shifted to the right with the Time Shift Tool (two sideways black arrows). This simulates gun muzzle echo.
It’s horribly manual, I’m afraid. I know you were looking for a single button press and go home.
Koz
Try using the Delay effect http://manual.audacityteam.org/o/man/delay.html
and the Reverb effect http://manual.audacityteam.org/o/man/reverb.html
I’ll resist 
John Williams can make proper orchestration apparent any torr vacuum. That’s one reason he’s so popular.
Koz
Thanks for the responses guys.
After messing around with Low Pass Filter and other effects I got the result I wanted.
So, thanks!
Also I know that there’s no sound in space.
But you know how movies and video games are.