Leapwing Audio CenterOne by Sound-Guy
A plug-in that can manipulate the phantom center of a stereo track while keeping the audio panorama intact.
Leapwing Audio CenterOne Stereo Processor v2
Leapwing Audio, as I’ve written in a related review, make some innovative tools that don’t try to look analog, or try to emulate what analog processing can accomplish, but do some almost magical things with audio. The CenterOne v2 processor is an update to their original stereo processor, and has some truly unique capabilities. As with their other processors, CenterOne can manipulate an audio sound stage very transparently, and with no degradation if the processed sound is collapsed to mono or if the left, center and right data streams are combined back to stereo (unless you’ve sent them through additional processors like reverbs or delays).
What is it?
CenterOne is a dedicated stereo “manipulation” processor, but far beyond anything I’ve used before. In fact it can extract center, left and right signals (LCR) from a stereo audio stream, and you can route and record these to separate tracks. CenterOne has two inputs (left/right) and five outputs: the processed left and right channels, and the extracted center, left and right components. If your DAW can directly handle multiple audio channels (like REAPER) you can directly record all these audio components, but even if your DAW doesn’t support more than stereo outputs from a plug-in, there is a simple workaround to record LCR signals (more on that later).
I never used version 1, but from what I’ve seen CenterOne version 2 has been greatly improved over that first version with improvements in the user interface, moving the Center Prominence control to the left (was on top), and the addition of a Level Trim control and a new Center Channel Width control. Leapwing also indicate they have improved the processing algorithms, which is always good to hear!
I tested CenterOne while testing Leapwing’s StageOne, a similar but quite different processor. While StageOne (see review) can manipulate both stereo and mono audio streams, CenterOne is strictly for stereo, and accomplishes nothing if you feed it a mono track. This is not a criticism - CenterOne is designed to adjust stereo imaging in various ways and extract LCR, and does so very well. For mixing and mastering it provides some amazing results.
On the left of the CenterOne panel is the Center Prominence control which has had its range extended from +/- 6 dB to +/- 9 dB since version 1. This adjustment enables increasing or lowering the central audio without any significant change of the overall stereo panorama, so with most pop/rock, the lead vocal can be pulled forward or pushed back in a full mix without otherwise changing the overall balance. It works very well.
The Level Trim does just that, raising or lowering the overall output signal level. This can be helpful to compensate for loudness bias if process settings cause the output level to change from the unprocessed state.
The main section, which was about the only process tool in version 1, is the LCR control, and this is where the magic happens. With all three of these channels on and set to the same level (and if the Center Prominence is set to 0 dB) the output will equal the input. Muting the L and R will yield the center only, like a mid-sides processor with sides muted. However, muting the C channel does not result in the same results as muting the mid in a mid-sides (M-S) processor. If you’ve ever used M-S processing and muted the mid, you’ve no doubt noticed the results are rather annoying, kind of like having your brains sucked out, because you are listening to sounds out of phase on the left and right speakers. CenterOne actually plays a left and right signal that sounds like the full stereo mix minus the center sounds. It is very different than M-S processing and enables effects like, for example, widening the stereo field without sounding “phasey” by increasing the L & R level a few dB over the center level. It also enables processing the left and right audio components separately from the center or from the whole stereo mix. And you can adjust levels of each component rather than just switching them on or off.
The purple bar below the LCR sliders is a bandpass filter control that adjusts low and high frequency cutoffs for filters (one, two and three pole are available) that allow including or excluding frequencies from the LCR processing. Playing with this and various LCR settings, I found an extreme range of possible processing effects
The Center Channel Width section at the far right operates on the stereo signal entering the LCR section, widening or narrowing the effective panorama range that is processed as a center signal. This does not adjust what frequencies are processed, but what postions in the stereo field are considered a center signal. This control is unlike the mono spread control in StageOne, although combined with boosting the CenterOne center channel it can modify the imaging, and it affects what stereo elements are split off as L-C-R audio streams.
My DAW is Old Fashioned
If your DAW can handle only two audio streams in a track, there is a simple workaround for recording LCR components described in the CenterOne manual. Basically you duplicate the track that contains the stereo audio file you wish to split into LCR, use a copy of CenterOne with the center channel off in one track and another CenterOne copy with L&R off. Send these outputs to two tracks set to record stereo - the first will record the LR signals on its left and right tracks (you can split these to two mono files if you wish) and the second will record the center as dual-mono (you can even record this as mono if you want). These three tracks can be processed in many ways, with different reverb, delay, harmonic exciters, and so forth on each (though you’ll usually want the L & R channels to receive the same treatment). Lots of fun to be had!
As many plug-ins provide, CenterOne has Undo and Redo (multiple levels), A/B comparison, and factory presets (and you can add your own). I found the Undo/Redo to be very handy when trying different settings. And all of these provide instant, glitch-free switching, so comparisons are not compromised by extraneous noises.
The Tech Details
CenterOne has a lot going on under the hood, but is not too heavy on cpu load. With any combination of settings I found it used less than half a percent of my cpu resource (I measured 0.44% with REAPER’s Performance Meter). Of course, for mastering work this is negligible, and even if used in a mixing project you likely could run a dozen instances if needed.
More Leaping Wings
Leapwing makes another spatial adjustment plug-in, the new StageOne, that works on stereo and mono signals, and does very different things than CenterOne. While CenterOne is designed to manipulate the phantom center while keeping the panorama intact (as well as extracting LCR audio streams), StageOne is designed to actually change the audio panorama. Take a look at the review.
Overall CenterOne is very impressive. It can modify the depth and width of stereo tracks, process central sounds separately from the overall stereo panorama, and extract LCR audio streams from a stereo file. While it is not a cheap plug-in, it is a very capable unit, and for anyone mixing or mastering at a professional level (even many hobbyists are doing so today!) it will provide very valuable utility. And Leapwing makes their products available in a fully functional demo for 30 days, so you can try before you buy.
CenterOne has a Retina interface and is available for Mac OSX (10.9 +), Windows 8, 10 (64-bit only) in AAX-Native, VST, VST3 and AU. However, all my tests, VST and VST3, were run on a Windows 7 machine (Pro, 64 bit, SP1) with no observed issues.
Unique processing algorithms for extracting LCR data from a stereo audio stream.
Ability to emphasize or pull back the center (vocals, bass, kick) in a stereo mix without affecting overall stereo panorama.
Five audio channel outputs for excellent flexibility splitting out stereo and LCR audio streams.
Very high quality results.
CPU usage is on the high side compared to most of your plug-ins, but it does things you can’t do otherwise!
64 bit only if you are stuck at 32 bits!
Not cheap, but quality never is!
CenterOne - Leapwing Audio