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NUGEN Audio SigMod

NUGEN Audio SigMod

5 5 out of 5, based on 1 Review

A simple "workbench" plug-in to add utility functions, add features missing in some DAWs, and create some very creative audio FX.

12th August 2018

NUGEN Audio SigMod by Sound-Guy

NUGEN Audio SigMod

NUGEN Audio are well known for loudness measurement and signal processing tools, and recently they’ve added a new, affordable custom signal processor that, for some DAWs adds missing features, and for anyone adds an extremely flexible set of functions.

Sig(nal) Mod(ules)
SigMod is a simple concept - a workbench window where you can place a sequence of audio processors in any order, from a selection of 11 modules, to achieve many different effects and audio corrections. The modules are Mid/Side, Protect, Mono, Switch, Delay, Phase, Trim, DC offset, Tap, Crossover, and Mute/Solo. Some of these are self-explanatory, but a few have extra features, including taps that can send audio to other DAW tracks using the included Receive module. SigMod uses very little cpu resources (less than 0.1% on my system using the 32 bit version in REAPER with the most ‘power hungry’ module, the Protect module, while the 64 bit version used slightly higher cpu resources). Any combination of modules adds no latency unless the Receive module is used in another track, and even this adds only 64 samples.

The layout is intuitive with the central area showing an interactive signal flow image - you can click buttons and drag values in boxes for immediate control of various functions, as you can see in the figure below. SigMod is designed for stereo audio, and there are always a pair of input boxes on the left and output boxes on the right side, but these may be Left/Right or Mid/Sides signals.

NUGEN Audio SigMod-fig-1-1.jpg
Master Bus preset with inputs, polarity inversion switches, followed by a Mono switch, a Protect module set at +3 dBTP, and the output modules. Left image has the mono switch off; right image shows it is on and you can see the Left/Right channels being combined and routed back to the original L/R paths.

You access the settings panel with the little gear button in the lower right, to modify presets and create new combinations of processing modules.

NUGEN Audio SigMod-fig-2-1.jpg
The settings panel for the Master bus preset - you can insert a module at any ‘+plus’ symbol.

There are a couple dozen presets included that have from one to ten modules (plus the always present Input and Output modules), and you can design your own signal architectures and save them as new presets. Note, you must type in the new preset name in the title window above the signal flow area to save with a new name or else it will ask if you wish to overwrite existing preset - took me a few minutes to figure that out.

NUGEN Audio SigMod-fig-3-1.jpg
A fully loaded preset showing both the interactive signal flow window and the settings window.

My Favorite Things
I originally tested SigMod in REAPER and found everything to work as expected, and was able to create some fascinating FX, and route signals around easily. However, REAPER can route audio (and MIDI) from any track to any track, so the SigMod track routing capability didn’t greatly impress me. The Protect module is great, if you don’t use REAPER which has had this function built-in for years. Protect is an audio level controlled switch that will instantly halt audio if it exceeds a set level - great for saving your ears when you accidentally send a few extra buses to your output. And REAPER has a polarity flip switch (erroneously called a phase control), so that functionality in SigMod was not needed in REAPER. But there were a number of useful functions to be found that are not built into REAPER.

And we don’t all use (nor do I always use) REAPER, and I know of no other DAW that has an auto-mute on the master bus. My other test platform was Studio One (both 32 bit version 3.5 and 64 bit version 4.0). Studio One does not have a built-in automated mute which was painfully demonstrated while I was testing some SigMod presets and accidentally sent a very loud signal to the main output. I had to slam the mute button on my audio interface (luckily it has one). I immediately installed a Protect module in the Studio One master bus as a post-fader insert (which is a great feature in Studio One), so I can’t exceed the Protect module setting even by pushing the master fader all the way up. I then ran tests and found the Protect module reacts “instantly”, even to a single sample exceeding your setting (-70 dBTP to +20 dBTP in 1 dB steps). I added the Protect module to all my Studio One templates, so I won’t blast myself again!

While testing in Studio One I went to invert the polarity of a track and remembered it does not have such a control (very odd in the 21st century!). So the Phase preset (that uses the Phase module, a misnamed polarity inverting module) is very useful in Studio One. And using the SigMod polarity feature enables flipping polarity of a single channel of a stereo track, which no DAW I know of can do.

And although Studio One has a good flexible bus system, you can’t extract a signal somewhere inside an FX chain and send it elsewhere. Using the SigMod Tap module and the Receive module can do this, although with the current version I had to put the Receive module in a bus rather than a normal audio track. It worked fine with the Receive module taking precedence over the normal track send to the bus. Very useful for creating some special FX.

Other Fun Things
I was able to create a quick vocal eliminator using the preset called Master Bus, by flipping the polarity of one channel, and then using a Mono module after the polarity flip. There is a Delay module that can provide up to 100 msec of delay adjustable down to a single sample, for both or one channel in a stereo track. Of course most DAWs have automatic plug-in delay compensation, but with some plug-ins these can be off a few samples, so it’s nice to have a tool to tweak delays. It would be better if this delay could be longer, one or even ten seconds would open up more uses.

You probably already have a mid-side to left-right converter, but if not, you can do this easily with SigMod, and include other functions like filtering (using the Crossover module) or switching operations at the same time. For example, while the Switch module swaps right for left, using the Mid-Side module you can use it to swap mid and side signals. The Mono module combines the left and right channels in a track to mono, and using a Switch followed by a Mid-Side, followed by a Mono module lets you instantly hear just the mid or the side signal. And using some Tap modules enables sending Mid or Side to other tracks for different processing.

In addition to the Tap module, whose only function is to split audio to send to a Receive module, there is the Crossover module which allows you to apply either a highpass or lowpass filter to the taps while extracting the complementary signal to its output. I checked this audibly by using pink noise and combining the track output after the Crossover module with the Receive module track, and as the crossover frequency was varied (from 20 Hz to 22 kHz) I heard no change, as it should be. The two signals add up perfectly to the original signal. And shifting one track full left and the other full right resulted in an image shift as the crossover frequency was changed. The filter slope of this module is fixed at 6 dB/octave, so you can’t make drastic cuts, but still it’s useful. And you can of course apply many FX processes to the Receive track which raises a number of fascinating possibilities.

In Conclusion
SigMod can add utility functions, add features missing in some DAWs, provide extremely creative audio FX with it’s included modules, and can link in various ways to other FX plug-ins you already have. How about splitting a vocal track into 3 or 4 different frequency bands and processing each with a different compressor? Or with a different reverb type? Or a combination of both? Or tap off a signal to a couple different delays. The Protect module alone is something every DAW should have, but few do. There is a demo version available so you can try before you buy.

Formats available: AAX, VST, VST3, AU and AudioSuite (64-bit versions only). RTAS is also available as 32-bit only. No iLok required.

Mac OSX 10.7.x / 512 MB RAM. Windows (64 bit) Vista or above / 512 MB RAM

Test Platform
PC Audio Labs Rok Box with Intel Core i7-4770K CPU @ 3.5 GHz, 16 MB RAM running Windows 7 64 bit. Tested in REAPER and Studio One DAWs.

Simple to use and extremely flexible.

Protect module can save your life (well, your ears at least!)



No real cons with the plug-in that I can determine, but would be nice to see an update with variable slopes on the Crossover module, like 12 dB/octave, 24 dB, heck, maybe even 48 dB/oct,for more extreme frequency cuts.

Also would be nice to have longer delays possible, at least a second, or more.

NUGEN Audio: SigMod | NUGEN Audio. Comes with NUGEN Producer and Post bundles; US$49 separately.

Attached Thumbnails
NUGEN Audio SigMod-fig-1-1.jpg   NUGEN Audio SigMod-fig-2-1.jpg   NUGEN Audio SigMod-fig-3-1.jpg  
Last edited by Sound-Guy; 12th August 2018 at 10:13 PM..

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