FireBird is a synth I had been looking at for a long time and was very interested in. Loved its easy to use yet powerful features/sound shaping possbilities. But something was missing for me. The sound just wasn't quite as nice as I wanted it to be. I always thought "gee, this synth just doesn't sound as good as it should, it's almost there, but not quite." Well, this issue has been fixed, big time.
FireBird+ is a huge improvement over the previous versions sound quality wise. The filters have been seriously upgraded, the overall sound is much better, and this synth is absolutely among the very best sounding software synths ever made.
As I already said, something I really love about this synth is the fact that it's really not hard to understand and it's quick to program, yet the sound design possibilities are remarkably broad thanks to the HCM synthesis approach. It's just really fun to work with. I seriously can't say the word "fun" when it comes to tweaking some other synths I like. FireBird+ is one of the very few that are powerful as well as fun to program.
If you're into synthesis in general and are looking for a synth that can give you the possibility to produce sound in a different way and that can give you powerful, mean sounds, lush sounds, windy sounds, organ sounds, and unique sounds you don't hear from anything else, you really shouldn't miss it.
It's now mid 2012 and this synth still holds up nicely, and the sound has been improved significantly again since version 1.8, but that was a while ago. Unfortunately, it seems that FireBird won't be getting some of the newer features and improvements like those featured in Tone2's Gladiator (newer HCM engine, better oversampling, newer filters), so it seems FireBird is pretty much abandoned in favor of the other HCM synth. It's still nice for what it is, and unique.
Edit: I'm leaving parts of my original review which may be useful. Mainly, I'd like to say that I'm disappointed that BiFilter2 is apparently abandoned, so do NOT buy it if you want a filter from Tone2, get FilterBank instead, because it has newer and better filter algorithms (which means better sound than BiFilter2).
Tone2 seriously upgraded BiFilter and released BiFilter2 which is a big improvement over the previous version, and I just had to get it.
One question may arise: why didn't I get Tone2's FilterBank2? The answer is simple, BiFilter2's big focus is on filtering and distortion features, just what I needed. (Edit: see top of review)
The sound is first of all very balanced! You actually get what you expect to get and the controls change the sound how you expect it to be changed, a quality that's seriously lacking in most filtering solutions. And the sound itself is lovely. This is the first software filtering solution I was actually satisfied with as far as sound goes.
The filter types are extensive. You can get very many kinds of filtering with it, and all sound quite lovely.
The distortion features are really unique and different from others I've heard, and can add a great character to the sound without ruining it. You can have it very subtle or extreme, and even the most extreme drive percentage is usable.
I would like it to have is an ADSR generator, but that probably won't happen.