Reverb Foundry Tai Chi - User review - Gearspace.com
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Reverb Foundry Tai Chi
5 5 out of 5, based on 1 Review

An incredibly versatile algorithmic reverb from the Foundry

22nd November 2021

Reverb Foundry Tai Chi by Sound-Guy

  • Sound Quality 5 out of 5
  • Ease of use 5 out of 5
  • Features 5 out of 5
  • Bang for buck 5 out of 5
  • Overall: 5
Reverb Foundry Tai Chi

Tai Chi from the Reverb Foundry

Just a month ago I “discovered” Reverb Foundry (a bit belated!) and the excellent CD-Cart emulation of the famous Lexicon 480L. At that time it was the only reverb product from the Reverb Foundry, and I mentioned there were hints for another. It has arrived – and wow! Rather than an emulation of a classic reverb, Tai Chi is an original design – and what a design!

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In case you wonder how I managed to test Tai Chi so thoroughly in only a few hours after it was announced, the answer is I was a beta tester and have been having a lot of fun with it for a couple months.

The Basics
Tai Chi is a modern take on the classic feedback delay network algorithm (FDN) and is a fully algorithmic reverb system that uses advanced diffusion techniques to eliminate ringing while able to employ extensive modulation capabilities to create rich, high density reverberation. Matt Hill, the reverb plug-in wizard behind both LiquidSonics and Reverb Foundry, has taken advantage of today’s computing power to incorporate many more, and much longer, delay lines than any classic FDN reverb could ever provide. He also added modulation wherever he could, as he said during development, “If I could stuff a modulator in somewhere, then generally I did!”

The basic GUI is clean with the usual housekeeping functions along the top row: A/B comparison, preset selection (load and save), access to a settings menu, and a help access (?) that can turn on an interactive helper. A bar graph level meter at the top right shows left and right channels either for inputs. outputs, early reflection signals, or late reverberation signals (momentary peak level of each channel). This is selected by a small pull-down menu at the right side of the meters. There are five tabs near the top, with MASTER selected in the above view, but with ADVANCED, DYNAMICS, FIDELITY, and EQUALISER tabs available to access four more sets of six controls each. The nine control knobs along the right side are universal, always visible, and provide the output mix control, early reflection/late reverb balance, and treble and bass contour adjustments. So in all there are 39 control knobs. This might seem to be more than enough, but in the lower left quadrant you can see a graphic area titled MULTIBAND REVERB TIME MULTIPLIERS. This adds an amazing amount of control over the decay times in different frequency bands with a generous range from 0.2 to 5 times the base decay time. And to make matters even more “out-there”, the base decay time runs from 200 msec to 90 seconds – so if you want a really long reverb tail, you can dial up to 7-½ minutes! All controls can be adjusted in real-time using MIDI automation, so the possibilities are endless.

All the Controls You’ll Ever Need
Looking at the Master panel we see controls laid out in two sections: Reverb and Reflections. The Reverb controls include Reverb Time (decay time in seconds for a 60 dB drop in level), Pre-delay (with a switch to sync to DAW tempo), and Width (stereo image control of the wet signal). Note under each (and every) knob there is a little padlock symbol which, sure enough, locks that control in place – a very handy feature it turns out.

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. . . . . . .Master panel with level meters showing early reflections

The Reflections section has controls labelled Pattern, Spacing and Roll-off, as well as a drop-down window to the right of the Reflections title (here showing ROOM). This section controls the early reflection attributes and has a wide range of possibilities with the drop-down menu selecting a general form of the space (Room, Hall, Church, Garage, and Stadium) and the Pattern control adjusting properties of the modelled space using letters and numbers. The letters control reflectivity of the room with A being the most absorptive and J being the most reflective. The numbers effectively change the relative position of the source and listener with lower numbers sounding closer to the source and higher numbers sounding further back in the space. The Spacing control adjusts the form of the individual reflections with higher values producing a larger sounding space. And there is a filter providing high frequency roll-off with both adjustable slope (from 6 to 24 dB/octave) and variable cut-off frequency (from 500 Hz to 18 kHz).

The next section is the Advanced control with Density, Diffusion controls, and a Chorus section. Density (which affects only the reverberation, not early reflections) controls how “smooth” the simulated space sounds, from specular (low) to smooth (high setting). Specular means there are discrete audible reflections far into the late reverb decay while higher settings produce a smooth reverberant field earlier. Some sounds like synths and sustained strings fare well with specular density, while others like drums, piano and full orchestrations work better with a smoother reverb decay.

Diffusion applies a smoothing function over the entire reverb – the higher the setting the smoother the reverberation. Diff-Size controls the “size” of the diffusers in the reverb generator and larger diffusers are slower to react creating greater time-smearing. Note that Diffusion and Diff-Size interact somewhat with Density when they are set to control the late reverb, but there is also an early/late icon between the Diffusion and Diff-Size controls that can switch control between early reflections and reverberation. So you can have extreme control of the smoothness of both early reflections and late reverb. Note when you switch control between these, the Diffusion and Diff-Size settings from the previous mode are maintained.

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. . . . . . .Advanced panel with level meters showing late reverb

The Chorus section has seven controls, a Thicken Chorus switch that creates a richer chorus when activated, and three Chorus modes (Enrich, the default mode providing gentle chorusing, Drift which adds slight detuning to the signal as it loops through the reverb structures, and Detune that adds higher levels of detuning in the loops to create a faster detuning of the audio).

There are also three knobs: Chorus adjusts the chorus level, Mod-Rate is modulation rate with high settings not only increasing modulation rate, but also increasing the rate at which the chorus will spread the audio signal out in the frequency domain, and Wander which controls how much a reverb tap can be randomly moved in time while it is fading through zero. These controls may seem a bit advanced, but those familiar with Lexicon reverbs should be accustomed to these types of parameters.

General Dynamics
The Dynamics section provides compression or ducking capabilities for either the reverberation signal only, or for the full wet signal (early reflections and reverb). This has the usual threshold, ratio, attack and release times, as well as a ”knee” control to adjust how abruptly the gain reduction occurs. There is also a trim knob to adjust makeup gain. The Ducking mode of reverberation-only is very effective for enabling a dry signal to cut through the wet signal. This mode is especially effective on vocals, allowing the early reflections to sound at their full level, which helps keep the sense of the room environment stable, while dropping the longer reverb level briefly to improve intelligibility. Note that both ducking and compression are not applied to the input signal – you can always use a separate compressor to address levelling issues of sources before entering Tai Chi.

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. . . . . . .Dynamics panel with level meters again showing late reverb

High or Low
The Fidelity section includes an input Bandwidth control, a “Bit Crusher” section and a Recirculation control. The Bandwidth control applies a “brick-wall filter” to the processor’s inputs “in a nod to those dramatic anti-aliasing filters of old that did so much to define the crunchy sound of many classic reverbs from the 1970s and 1980s”, as the user manual states. Some very expensive hardware in the 70’s and 80’s had bandwidth limited to 16 kHz, or even10 kHz, as well as processing with only 18 bit, 16 bit or even 12 bit digital resolution.

The Bit Crusher can reduce the resolution of the total wet signal (reflections and reverb), and separately set the bit levels for the input signals to the reverberation and to the reflection processors. The bit reduction can be set as low as 6 bits (very crunchy!) up to 17.99 bits (as close as you can get to 18 bits) or Full, which is 32 bit resolution. These three controls provide a wide range of subtle to very “gritty” results.

The Recirculation control applies to the audio signal as it recirculates around the reverberation loop (which is what creates reverberation!) and enables adjusting the depth of modulation and the resolution. Setting the Depth value high creates a livelier reverb sound while low settings taper off more evenly. Low Resolution settings will cause the audio within the reverb loops to get “fuzzy” as the level fades, and then “gate-out” as the level falls below the bit-depth horizon. This can be used with extreme settings for some very “punchy” effects!

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. . . . . . .The Fidelity panel with level meters showing overall output levels

The final panel is an EQ section that includes low and high cut filters with four selectable slopes from 6 to 24 dB /octave and a low shelf and high shelf, each with a two-pole filter design (Q of 0.71). All EQ filters affect the mixed wet signal (reverb and reflections), but not the dry signal.

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. . . . . . .EQ panel with level meters showing input levels

Band Time
The Multiband Reverb Time Multipliers section provides very effective shaping of the decay time versus frequency using either three or four bands. The multiplier adjustment can be set both graphically by dragging the top band edge up and down, or using the set of sliders below the plot, or clicking on the value window for a given band and entering the desired multiplier. The frequency split points can also be adjusted three ways, by dragging the vertical split line between any pair of bands, or using the slider or data entry method like the multiplier input just described. These parameters can even by changed on-the-fly as music is processed which results in smooth changes to the times and multipliers – a powerful way to change ambiance for different sections of a song.

And There is More
Of course you can use your DAW automation to adjust any of the over fifty parameters in real time – and most adjustments result in smooth changes to the reverb results without any clicks or pops. And if you need reverb processing for more or less than stereo audio, Tai Chi supports mono, stereo, LCR, Quad, 5.x, 7.x and 7.x.2 formats. Of course your DAW needs to provide adequate audio channels per track for formats betond stereo (Reaper sees up to ten inputs and outputs with Tai Chi). Note that even with only a stereo input, Tai Chi can generate a front reverb pair, rear reverb pair, a centre reverb, and two more pairs, side and height as needed, if your DAW can handle it. This is ideal for up-mixing a stereo signal into surround sound, either using simple early reflections, or as a full reverberant environment. The Tai Chi reverb channels are fully “decorrelated” which means they are all slightly different and can be combined to mono with no phase cancellation issues.

There is also a Tai Chi Lite version with reduced controls (Mono or stereo only, chorus and deep modulation control, simple decay contouring, 4-band master EQ and 25 presets) if you are on a tight budget. But if you love tweaking reverbs, the “full fat” Tai Chi is ne plus ultra!

Tech Data
Tai Chi is available in 64 bit VST2.4, VST3, AU and AAX formats for Windows (Windows 7 or above) and Mac OS X 10.9 or above. Note that Macs running on Apple Silicon are currently supported via Rosetta 2. Native support for Apple Silicon is targeted in 2022.

Tai Chi uses the iLok/Pace activation system and operates with iLok 2 or 3 USB dongles, iLok Machine Activation or iLok Cloud. Since the iLok system is often updated, be sure to check iLok.com and download the newest version before trying to use Tai Chi (it requires iLok License Manager ver 5.4 and up). And be sure to be online when you first open it in a DAW because you will get an activation screen that needs to connect to iLok. Enter your activation code and then go to your iLok account to select the activation mode you want. Both Cloud and Machine activation are free, but Cloud requires being actively online whenever you first start using an instance of Tai Chi in a project.

In my test system (PC Audio Labs Rok Box PC with Windows 7, 64 Bit, 4-Core Intel i7-4770K, 3.5 GHz, and 16 GB RAM) Tai Chi in stereo mode uses from under 0.25% CPU resources up to about 1%, depending on settings. In general, if you use only early reflections you will have the lowest CPU load (and this is great for small rooms, vocals and some instruments to add space without a long reverb tail). Tai Chi will automatically detect how many audio channel are on its track, and at the full ten audio channels in REAPER the maximum CPU use I observed was just over 4%. RAM usage is a modest 110 MB and there are no large sample folders involved since Tai Chi is algorithmic. Latency is zero.

Tai Chi is an algorithmic reverb that sounds better than a convolution reverb! It provides very clear “3-dimensional” spatial environments and handles emulations of small spaces without the metallic ringing or buzzing of many reverb processors – the small rooms really feel like a recording made in a small room. And the large spaces feel open and, well, large. Listening to the end of a long decay with the gain of my DAW boosted 60 or 80 dB (don’t try this at home!) presents a clean fade to extinction with a natural sounding fluctuation in tones and level. Unless you use the Fidelity section to reduce the sound to a crunchy fuzz! Even a mild reduction to 16 or 12 bits can create a kind of gated effect in the decay tail which can be effective for some productions.

Extremely flexible algorithmic reverb with superb sound quality with luscious chorused reverbs and more modulation FX than a beaver has whiskers.

The Multiband Reverb Time Multipliers section is “da’ bomb” enabling adjusting the evolution of the tone and time of the reverb over the frequency range, even making changes in “real-time”.

Decay times can be out of this world – up to 450 seconds – 7-½ minutes!

Fidelity parameters can add serious grit if needed, or subtly emulate the reduced resolution and fidelity of classic hardware reverbs.

Dynamics control is excellent with ducking and compression able to be used on the full wet mix or just on the “long” reverb which can greatly improve the clarity and intelligibility of vocal phrases or instrument solos.

Factory Presets (75 of them) are excellent examples of the range of reverbs possible.

Excellent GUI with logical, easy access to the advanced controls.

Supports mono, stereo, LCR, quad, 5.x, 7.x and 7.x.2 formats if your DAW can handle it.

Tai Chi Lite can also be used with a license for the standard edition of Tai Chi and during the intro period both versions are at half-price (until December 20, 2021 as posted on the Reverb Foundry website).

I really can’t complain about what Tai Chi can do – it’s amazing. One possible enhancement for a future update would be more control and more display info for the surround channels – right now the surround output levels are fixed and only an overall level is shown on the input/output meters. Of course in your DAW you’d most likely split surround channels out and could adjust levels, change EQ, apply dynamics, etc. in the additional tracks or buses. So lack of more multichannel control within Tai Chi is not anything I’d lose sleep over.

See https://www.reverbfoundry.com/tai-chi/

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Last edited by Sound-Guy; 23rd November 2021 at 06:37 AM..