Sound Tool for Making Buzzing Sounds?

I put a few games in development on hiatus for the Humble Bundle contest and made a game about a song from playonloop.com. So far, I learned more about using the blocks in 3.3.2, and the testing for all of the games became fantastic! However, I needed to make  unique bug sounds for all of the game's enemy types. What kind of sound tool/filter/plugin can I use to make them?

Try bfxr
http://www.bfxr.net/

I know how to use it, but I need to know what combination of filters do high and low pitches that sound like a unique insect. Like a hornet dying or king insect defeat echoing.

I have two sounds I made on Stencyl Forge that might work, errie scream and evil grunt. (yes, I misspelled eerie).

Check these out. If I can lower the notes in the rest of each file, dying sounds would be a breeze!
The following are cc0 in the post.

I found a great tool the other day for generating sound effects (SFXR) from site http://www.drpetter.se/project_sfxr.html or online version http://www.superflashbros.net/as3sfxr/

once you generated a sound load it up in Audacity and add some depth to the sound, compressor and reverb I find works well, doing this way you will quickly end up with an assorted pack of sounds that you own outright, so recommend this to anyone!

EDIT, NM, didnt see link in 2nd post, that actually looks better

Try bfxr
http://www.bfxr.net/

That's a pretty fantastic tool, even got a sequencer for layering sounds I absolutely love it, thanks for the link

How do I add the depth? I'm working on it right now.
Edit: Used the Delay filter. Hooray!