SIR vs other convoluted reverbs

Besides the “cost” factor, a lot of people seem to really enjoy the flexible tweakability of Waves IR-1 and/or Voxengo Pristine Space.

What are the the differences between the 3?
It seems like with SIR you really cant control the dampness or early reflections.

First, a disclaimer – I haven’t used any of the above yet. But I know a little of the theory.

With a pure convolution-based processor, one that’s not intended as a reverb per-se but as a processor that applies a convolution filter kernel (a.k.a. “impulse file”), you have NO controls other than on, off, and simple mixing controls like %wet/dry, pre/post gain, etc.

A true pure convolver has no preconceptions about its job. It simply applies the convolution kernel. As such, it can emulate any infinite impules response filter – i.e., just about any natural process that’s not chaotic (and I’m not sure about the chaotic thing either). Tube amps, speaker cabinets, room acoustics, the list goes on and on. However, the big limitation is: while it can imitate anything, there are no adjustments. So, whatever knob settings you dialled up on your JCM9000 when you recorded the impulse to derive the kernel, that’s the settings you get when you use it on a pure convolver. Want to back off a little on the gain, or boost the midrange a tad? You need a different impulse file. No adjustments are possible.

Any convolver that has “damping” or “early reflections” controls is including some of its own preconceptions about the kind of reverb. Either that, or it’s making assumptions about the characteristics in the impulse file that correspond to these features and adjusting the kernel accordingly – which I would be surprised to find is possible. If I interpret it properly, Voxengo specifically doesn’t make any such assumptions. And yet it’s sold as a “reverb” unit. So, I’m not sure about what it really is and does: if it’s just a convolver, it can do much more than merely reverb.

If you want to control damping and early reflections, use a purpose-built reverb like n-Track’s, which I like and has a great control set. Of course, you generally need more than one reverb because each has it’s own range of sounds.

SIR is great for what it is, but what it isn’t is “tweakable”. That’s just not in the cards, given the internal workings of the beast and what it’s supposed to do. On the other hand, you won’t find “Carnegie Hall” in n-Track reverb or any other “artificial” reverb. (I don’t mean that term in any negative sense, btw.)