Guys I'm going through a library and it has two categories stated as Downlifters, and impacts. (along with uplifters)

but Downlifters and impacts sound same to my ears? they both tend to fall down in pitch over time, whats the difference? can u explain? thank you

 

Not quite the rule of thumb, but: the impact has solid transients at the begining - is something that starts with a percussive element, for example "thump" (kick, tom, snare) or "crash". The impactless downlifter may be just a filter sweep (rolling of the high frequencies) - or progressive pitch down - over a given sound. A snare hit with huge reverb with long tail can be an impact. A simple sweeped white noise is just a downer. Get those two layered and you have a impact with downer.

 

Agree.

Think of downs as the opposite of risers, which is just a gradual pitch bend up over a length of time.

Impacts are usually "cinematic" in the sense of they'd make someone jump out of their seat in a movie theater because of the percussive strength, bass content, volume, etc. Impacts are just that, full of impact. Tympanies combined with an anvil would be an orchestral type of impact, something like the Terminator 2 theme.