I need a good sound effect for a slow (12s) sci-fi "charge up" sound. I found this (rising tone starts around 0:21), which sounds great, except that right near the end there's a massive rattle in the sound which just sounds terrible (and there's some other noise earlier that detracts from the tone). I'd like to remove it, but I'm a total newbie to sound modification. I've opened the sound up in Audacity to take a look; the rattle is visible in the waveform starting around 35.5s in. From what I recall of the engineering course I took in college, if I had the frequency of the rattle, I could use an FFT filter to truncate the noise out. But experimenting with the FFT filter in Audacity shows that the rattle appears on all sound frequencies (or at least, I can't seem to remove the rattle without removing important parts of the rest of the sound). I've had no luck with the "remove noise" effect; it prefers to remove the tone instead of the noise, which is annoying. Any ideas? About all I've come up with is to stop the rising tone before it gets to that point in the sound...which isn't really an approach I fancy.

iZotope's RX has one of the best audio repair interfaces I've ever seen.


Oh, and please be aware that there's a terms of usage with the sound files and make sure that editing them for your own uses is covered under that--generally, I'd suggest the challenge of making the sound yourself.

Especially since charge up and sci-fi sounds are synthetic and fairly simple.

iZotope also costs $350, and I'm on a strict budget here. I also have basically no experience with modifying sounds or recording them; the only equipment I have that could record sounds is a digital camcorder.

The sounds at Soundsnap are royalty-free and you're allowed to modify them. I checked.