Yeah, if you already have a Multi-band you already love, don't spend an inordinate amount of cash for something like this. I use it only for Mastering, and I rarely use one when I Master. However, when I need it, I'm rarely disappointed with it. The Waves LinCompressor is also great for Mastering, although far less feature-rich. I believe Sonar has a VST Multi-band, Ozone 5 is great, and Sonar Producer comes with a very useful Multi-Compressor.
 
I should also mention that Alchemist is currently only 32-bit, although I'm told the next wave of v3 products converted by Flux will include the Alchemist, which will bring it up to 64-Bit and AAX support.

Sanderxpander

AJ_0000

Sanderxpander
I have it and I'm just wondering why. I think it's one of the oldest perhaps? Even Waves have since then moved on to C6 and LinMB. C4 doesn't have the best reputation for transparency, even with the bands switched off, ultimately leading (more than ten years later) to people like FabFilter trying specifically to keep audio completely transparent when not processed.

In truth, I doubt many top mix engineers use multiband compressors very much. They may be slightly more prevalent among mastering engineers, but I'm not sure about that either. The impression I get from the top mixers is that they prefer to use parallel compression (create a copy or aux with all but the desired frequencies filtered out, then hit it with a regular compressor and mix it back in), which is unquestionably a better way to do it, albeit much more time consuming.
 
That's what the Manny Marroquin Tone Shaper plugin does - multiband parallel compression. It gets pretty nice results too, for being kind of a simplification of that process in a single plugin.

It may be part of the underlying tech of Pro-MB too, since it lets you create bands freely and doesn't process audio where you haven't created a band.

Yep, but anything you do going through a plugin is going to have more potential for artifacts than true parallel compression.

In other words, it's the same as the MM Tone Shaper? :)

Sanderxpander
In other words, it's the same as the MM Tone Shaper? :)

Right. The same thing applies to both of them. Any plugin you're inserting directly into the signal path, that splits things into bands, as opposed to doing it parallel the way I described.

Ah in that case I disagree. Pro-MB has a wet/dry balance too. I do understand your point, but the convenience far outweighs the possibility of one plug screwing up, especially when it specifically states to leave the dry signal completely untouched.

Sanderxpander
Ah in that case I disagree. Pro-MB has a wet/dry balance too. I do understand your point, but the convenience far outweighs the possibility of one plug screwing up, especially when it specifically states to leave the dry signal completely untouched.

Plugins are pretty good now, so it's less likely you're going to get severe artifacts. But still, doing it the other way is ideal. Especially considering that the big name guys do it using expensive outboard gear.

Doing it the other supposedly "cleaner" way means using more plugins and more tracks. Let alone rerecording using analog outboard.

what about softube drawner 1973? parallele Multiband
seems good. but for master bus? not sure.
http://www.softube.com/index.php?id=drawmer1973

Came to this thread because LP-64 in Sonar X3 crashes my computer every time I open it. That and I also use Sonar more for synths and PT for mixing. I bought A UAD-2 Solo used but haven't heard from the seller in a week (gonna have to call e-Bay soon) or I'd go for the UAD plug-in. I need it for taming palm mutes on heavier guitar tracks which I've done with the UAD plug-in in another studio before to great results. Around 110 to 120 Hz it always seems in my case. 
 
Basically I've got a great guitar tone that sounds great 75% of the song until the 25% which has palm mutes jumping out dramatically in the speakers. So I turn on two bands for the multi-compressor, one below the target frequency range and one for the target frequency range. I set the ratio to around 4:1 and the threshold so that its only triggered by the palm muting. My intent being to pull the palm mutes down to the same level as the rest of the signal so that the guitar tone remains balanced during that 25%. 75% of the song the signal just passes through the plug-in. This is a general example of what i use it for. 
 
I've tried the sonitus MB, and the MB that comes with reaper, plus some other free plug-ins and it never worked out for me. Maybe the UAD one just worked better with my skill set or maybe it just worked better for my application. Maybe it's more transparent. I believe it's the only one I've used that adds latency to the signal. UAD on the page for this plug-in claims that is because it comes with the territory in how the special processing works in their MB. So maybe that has something to do with it, or maybe it's BS. 
 
I don't know how long my UAD prospects will be tied up in this eBay situation I find myself in, so I was thinking about buying the C4. Something around $150, preferably less. 

Guitarpima
I still don't get it. Just like de-essers, I think the best way is to go in and lover the volume on the specific culprits in the wave file. It seems the easiest way rather than suck the life out of the track.

here is how I look at it.
 
I compress each individual track as needed.  I buss similar instruments, and then I compress those buss as needed to glue each instrument group together.
 
here is where things can get funny.
 
once you are mixing everything down to that one stereo bus and putting it all together.
 
Some 'glue' obviously helps here as well, and this is best accomplished with some compression.  But I dont want a "one size fits all" compression.  The attack and release setting and amount of compression on every track I compressed, and every buss I compressed is tailored to the specific instrument and what my ears think sound good
 
my drum compression for example is going to look different than say lead guitar compression
 
so when I go to compress that stereo buss to glue it all together...  I certainly dont want to be limited to 'one type of compression' if you will.
 
I want things to sound transparent as I "glue" them.  Being able to set individual attack and release on each band alone is good enough reason for me to use a multiband, because then I can preserve as much 'dynamics' and transient material as I want from one instrument group to the next via isolating their frequency ranges.  Basically all it does is help me glue the track together and get a little more volume out of it without destroying certain elements of the dynamics
 
same thing with a de - esser.  A smart de-esser compresses the frequency band where the SSSS is at.
 
eq vacuums out the frequency.  If you ask me...  this can be more destructive as its actually taking out the sibilance in its entirity, which could pull all the air out of the track everywhere and not just on the ssss that gets out of hand.  A good de-esser doesnt do that.  It catches that sssss and compresses it and holds it to a non obnoxious level.  otherwise leaving the sibilance in tact.  when the vocalist isnt ssss'ing, its nice to have those airy frequencies still available for every other word