Sidechain Input Compressor - Alternatives to Sonitus Compressor

I've been using Cakewalk Sonar X3 Studio for a while now and for mixing purposes I have been using a combination of the free plugins that come with it and a whole load of freeware VST stuff (TDR, Molot/VladG, TB, Variety of Sound, Shuttlebug, etc, etc). While there is a wealth of excellent free plugins out there for, I've so far been unable to find a plugin compressor that has all of the options and functions of the Sonitus compressor, which has a lot of useful features.

It's a pretty decent all-purpose compressor. One can vary the ratio from 1:1 - 30:1 or Infinity:1, the attack time can go down to 0.0 seconds for fast limiting. It has a highly flexible hard/soft knee. Basically, it can meet almost any practical compression/limiting application. For some tasks, the actual sound of the compressor is not amazing, but I use it so often because it has these functions that the others do not.

The main thing that it has over all the other plugins I use for compression though, is that it can be used as a sidechain compressor.With the Sonitus, I can use sends from other channels as Sidechain inputs into the Compressor to trigger the compression/ducking/pumping - ie with kick/bass sounds. I can't get the option of sidechaining with any of the other compressors I use. At least not in the same way or that I am aware of.

Also regarding the Sonitus compressor, when it comes to compression on instruments for bass sounds (ie bass guitars and kick drums/toms), I prefer the way something like the TDR Feedback compressor sounds on the low end - fatter, rounder, warmer, more 3D. These tend to be the sort of instruments where sidechain processing is most useful for the kinds of music I work on. This is a slightly less pressing issue than the simple ability to sidechain, but given that it is these instruments and frequencies that I am mostly looking to use sidechaining on I thought it worth mentioning.

I know if might seem like a big ask, but can anyone recommend any (preferably free) VST compressors that have this function?

I know there are probably a number of top-flight plugins that cost varying amounts of money, but as a general rule of thumb I prefer to spend my money on actual physical hardware rather than software that is usually obsolete far more quickly. I've also stopped using cracks and ripped software. Of course I am willing to bend this rule if there is a great piece of software that meets my requirements.

Any suggestions appreciated.

I'm not at my DAW right now, and I may be wrong, but doesn't the Molot have an external side chain mode?

I think most plugins need to be VST3 to offer their sidechain inputs to Sonar, or at least that has been my experience with them. Maybe I didn't look well enough before.
 
I don't have any free suggestions but FabFilter Pro C2 does everything you could want and more. It's not cheap though. 

Ah thanks for that, I do have a sizeable Waves collection and never had any sidechain inputs appear other than Sonitus until VST3 arrived. Go anecdotal evidence! :) 

Gideon K
fjz - I haven't managed to find a way to sidechain using the Molot. So if it can be done, I'd be very interested to hear how. On the single channel version - the one that is just bars, numbers and letters (ie not the version that looks like the inside of a russian tank) I found a way to have an external sidechain input but couldn't get the paramaters working in a satisfactory manner.

Hi Gideon,
 
I`m not sure if you`ve tried this or not, but on the Molot GUI, there`s a little arrow at the bottom left side that can be easily missed.  If you click on that arrow, you will see some extra parameters that includes one where you can change the side chain from internal to external.  Also, I would make sure to have the latest version as this feature may have been added sometime after it`s initial release.
 
Hope this helps

The free Melda compressor is surprisingly good and is sidechain enabled...

https://www.meldaproduction.com/MCompressor

pc4k exp/gate pro channel module has sidechain