Have you ever wished convolution reverbs could be a little more malleable?
If the name Paragon sounds familiar, it might be because you read Sam Inglis’ article in SOS November 2020 (https://sosm.ag/Paragon) about the genesis of this NUGEN Audio plug‑in. And if you haven’t read that article yet, I’d urge you to do so before reading this review, as Paragon is no ‘ordinary’ reverb plug‑in and Sam’s article provides helpful background to its development and underlying technology.
As many other reverbs are now, this one is based on convolution. But, while practical convolution reverbs have been around for over 20 years now, Paragon is no ordinary convolution reverb either. Based on groundbreaking research and three years of intensive development by Dr Jez Wells of the University of York and NUGEN’s own software geniuses, Paragon employs additive resynthesized impulse responses. This is a highly innovative technology which Sam explains well in his article, but the brief version is that impulse responses captured in real spaces are analysed to create a model which can be modified through a process of resynthesis.
This intriguing technology enables complex reverberation fields to be generated which combine the exceptional sonic accuracy and realism of convolution reverbs, but with the ability to be tweaked and modified in the same way as traditional algorithmic reverbs. So fundamental parameters that shape the character of a reverb, such as decay time, room size, and HF and LF damping, can all be adjusted on the fly, almost in real time. Because the reverberation field is produced by individually resynthesized impulse responses, changing parameters doesn’t result in the processing artefacts that blight systems that modify impulse responses through, for example, time‑stretching techniques.
You’ll probably have noticed that I said ‘almost’ real time. Parameter adjustments do inherently require a brand‑new impulse response to be calculated (the resynthesis part) before it can be used in the convolution process, and that recalculation obviously takes a finite time. NUGEN’s Paragon plug‑in very cleverly subdivides this resynthesizing workload into separate calculations for different frequency bands, and for early reflections separately from decay tails, too. All of this dramatically simplifies and speeds up the resynthesis of new impulse responses.
When a reverb parameter is changed, the NUGEN badge at the top right of the plug‑in window spins around while the number‑crunching is being done, but even on my ancient Windows 7/64 computer it’s usually a case of ‘blink and you miss it’: typically it only takes a few tens of milliseconds to recalculate and implement the IR updates, and in practice I found recalculation delays to be insignificant, and certainly no impediment while...