Ambience Enhancer is a clever 64‑bit VST3/AU/AAX plug‑in for Mac OS 11.0 or above (there’s no Windows version), and it runs on both Intel and Apple Silicon processors. Authorisation is by a licence key, which is emailed on purchase.
Essentially, Ambience Enhancer analyses the incoming signal and separates it into two parts: ambience and direct sound. This allows you to control the ambience as you wish, while leaving the direct signal unaffected. NovoNotes say they achieve this by analysing the phase differences between channels, based on the principles behind M‑S encoding — and that means, of course, that it can’t do anything for mono recordings. There are currently two versions: the standard version (reviewed here), which can handle multi‑channel sources, and a Lite version, which is stereo only and free to download. A third ‘multiband’ version is also planned.
The GUI is pleasingly simple and the controls self‑explanatory; you won’t need a degree in manual reading to get instant results. On the left are four horizontal slider controls, and on the right a pretty visual representation of what’s going on. Top left, the Ambience Gain slider allows you to apply up to ±12db of gain to adjust the amount of ambience already present in the sound. Next comes Ambience Low Pass, a variable (3‑22 kHz) low‑pass filter applied across the Ambience signal path only. Ambience Delay is, effectively, a pre‑delay: it can apply a 0‑50 millisecond delay to the Ambient signal path. Finally, there’s an overall Output Gain control (not included with the Lite version), which allows you to compensate for the overall level changes inherent in this process.
Double clicking any slider will reset the position of that slider back to its default flat setting. Also, hovering over a slider’s name will give you a detailed description of the function of each control should you need it. A button accesses a Settings pane, where you’ll find your license info and licence type (you can purchase a month‑long licence or a perpetual one), and if running the plug‑in on anything with more channels than stereo, you have the option to bypass channels that are assigned as LFEs.
I first tried Ambience Enhancer on the stereo drum bus of a song I’d mixed a few months before. The drums were recorded in a medium‑sized (roughly 8 x 12m) room, with the kit close‑miked at one end of the room, a mono room mic about 1m in front of the kit, a stereo room configuration halfway down the room, and another stereo pair at the far end of the room. These drums sounded natural, fat and punchy with a nice bit of room ambience mixed in with them. With Ambient Enhancer, I was able to dial in a little more room sound on the stereo bus without losing clarity or weight in the close mics. Obviously, bringing up the ambience made things brighter — there was a lot of cymbal sound in those room mics — but the Ambience low‑pass filter made it easy to compensate; I could ensure things sounded natural and in‑keeping with the original sound.
Next, I opened my Dolby Atmos mix of the same song, with the same kit running through a 7.1.2 bus — the sound was more ‘around me’. The main kit sound was coming from my front L, C and R speakers, with the closer stereo room mics assigned to my side speakers and the far mics to the rears. Again, using Ambience Enhancer across the 7.1.2 drum bus, I could bring those room mics up nicely, without affecting the drier close mics.
When working on Atmos mixes it’s not always possible to access the individual channels — I’m often sent stereo stems... so I can see Ambience Enhancer being very useful.
Of course, in these specific examples I could simply have raised the level of the room mics in the drum bus, but when working on Atmos mixes it’s not always possible to access the individual channels — I’m often sent stereo stems from someone else’s stereo mix, so I can see Ambience Enhancer being very useful. It would be possible to make a copy of the stereo drum stem, add an instance of Ambience Enhancer to crank up the ambience on that channel, and follow it with your upmix plug‑in of choice: you’d then have the ability to spread the natural ambience of the stereo drum stem around the other channels in your immersive environment.
I also tried Ambience Enhancer on a stereo electric piano, with some reverb ‘baked’ into the recording, and it really shone: I could open the sound right out and bring up the reverb without drowning the dry signal or compromising the piano’s attack. Pushing in just a millisecond or two of Ambience Delay opened it out even further, all the while retaining the integrity of the original sound. Going the other way, backing the Ambience Gain off a little dried the signal in a very natural way, making the piano sound a little more forward and prominent without any sonic detriment.
As with M‑S balancing, things can start to sound a bit weird if you push things too far. Too much Ambience Gain can seem to leave a hole in the middle, while backing off the Ambience too much can give a mono effect. Used judiciously, though, Ambience Enhancer is a subtle way of bringing out or reducing the natural ambience of any multi‑channel sound source.
While very useful, it’s probably not a plug‑in you’d use every day, which is perhaps why NovoNotes offer a very reasonable monthly licence. But if you work with stereo stems in immersive audio, with bounced stereo mixes where you wish the mixer had backed off the reverb just a touch, or if you’ve been sent a mix project in which the only drums are stereo loops and samples, Ambience Enhancer offers a very quick, easy and sonically satisfying way to dial in just the right amount of ambience and space.