Review – Quadravox by Eventide

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One of Eventide’s latest offerings is a powerful harmonizing plugin with many useful features – yet another inspired offering from this innovative company.


by Rob Mitchell, Mar. 2017


Eventide is one of the top producers of quality hardware and software music products. They’ve been around since the 1970s, starting out by creating pioneering hardware for musicians and producers alike. As time went by, they also started to produce software products. Some of these include UltraReverb, H3000 Factory, and the H910. For this issue of SoundBytes, I will be looking at one of their latest products which is called Quadravox.

What is Quadravox? If I had to just sum it up, I’d say it is a harmonizer effect plugin. There is no way I can just leave it at that however, as there are many extra features within it. I will go over what’s included in this effect plugin, and we’ll see how it works.

Quadravox requires the PACE iLok License Manager to be installed, and it can be used with or without an iLok dongle. It is compatible with Windows 7 or higher and Apple OS X 10.7 or higher.  It is available in VST, AU, and AAX Native formats.

During the install, you’ll have the choice of which format to install. I have a PC, and it gave me choices of AAX, AAX64, VST32, and VST64. After you have the installation out of the way, the next thing you’ll probably want to do is to hear what this will do to your audio. You can use Quadravox on an effect bus, or directly on a track for whichever synth or sampler plugin you are using. If you want to use it on bass, keyboards, guitar, or vocals, you could just apply it to the appropriate audio track, or use an effects send.


Getting Started

Once you open it up to view its display, you’ll see the browser at the top-left. The presets are divided up into these categories: Harmonies, Rhythms and Delays, Sequences, MicroPitch Shifters, Other Worldly, and Special FX. You’re also able to browse by the preset author, or view the presets alphabetically. There are a good number of and much variety in the presets, but you will probably want to design some yourself at some point. To do this, you can select the “Default” preset from the dropdown menu. It is similar to an “Init” patch on a synth plugin, as it is very simple and lets you design from the ground up.

In the upper-right there a few handy features you should know about. “Live Mode” is a switch for the latency within the plugin. With it turned off, it will use 40ms of latency. The delay compensation in your DAW can then be used, and can help with improving the pitch detection. “Key Lock” will keep the tuning settings you’ve selected as you switch between presets. “Mix Lock” is similar to Key Lock, but it keeps the Mix Level the same as you change presets.

The top part of the display is mainly taken up with the Voices editing section. It has four sets of identical voice controls. Along the left are the On/Off buttons for each voice. Each voice has level and pan controls, letting you make adjustments to their volume level and placement in the stereo panorama of your audio. The next section to the right is for Delay and Feedback.

Delay is used to play a voice at a certain point in time, and it ranges from 0.0 to 2.3 seconds. When it is set to zero, the voice will play immediately. If it is set to some sort of delay time, you’d hear the voice at that specified time. The Feedback control adjusts the amount of the output that will loop around and feedback into the input. The last section is for controlling the pitch. This can be adjusted with a range of +/- 2 octaves. The pitch control is in interval steps (2nd, 3rd, 4th, etc.), and you’re also able to fine tune it using Cents (+/-2,400 cents).


The Big Pitch

For most situations, you will probably want the Pitch Tracking/Detection on. For other times, such as a guitar playing notes in a chord (arpeggiated, but letting them sustain over time), you may want to switch it off. If you leave it on, you might hear glitches in some of the harmonized notes Quadravox creates for the guitar. You might also want to turn it off for any instruments that aren’t tuned. Drums are a good example, or some other percussion that isn’t normally pitch-based. When it’s turned off, the incoming note is the root of the scale (even if it is a drum or something else). The “Instrument” menu has settings that lend themselves to various instruments. It will set the low note so it closely matches the type of instrument you selected. This helps out the pitch detection, as then it won’t listen for anything below the low note you have selected. You can also set the low note manually. Using the “Crossfade” control, you can blend out some of the glitchy types of sounds I mentioned before. Shorter Crossfade settings will have faster tracking, and conversely, a higher setting will have slower tracking. 

 The “Random” control will add an amount of micro pitch to each voice. I think of it as being similar to oscillator drift in analog synthesizers. Using a slight amount of this can yield a more realistic harmony, as no one has (for instance) perfectly tuned vocals or guitar/bass strings. There are ever-so-slight deviations in the pitch over time, and this feature helps to emulate that life-like sound.



In the bottom half of the display, there are the Input and Output controls, and a Dry/Wet mix slider. To the right of that section is the Notation Grid. This will display where the individual voices are located with respect to their place in time, and the note to which they have been assigned. You could drag the voices around with the mouse (up/down to change pitch, and left to right to change the delay), or as I mentioned earlier, use the Interval and Delay controls to do the same thing. You can’t get the fine tuning that the Cents control provides when you use the Interval settings, but it is a quick way to get the notes where you’d like.

Setting the “Key” and “Scale” allows you to set the notation to work in the best way possible to suit your musical project. Key is of course the key of the music, and the Scale setting allows you to set it up with common types such as Major (Ionian), Minor (Natural, Harmonic, Melodic), as well as many other modes (Locrian, Lydian, etc.). Other controls in this section of the plugin include a Master Tune, Sync to host, Tempo control, and Meter. Loop Delay will repeat the voices you have set up at whatever timing you have it set to. For instance, if it is set to 2.4 seconds, it will play the voices initially, and then play them again in 2.4 seconds. The “Feedback” setting controls how long it repeats the loop. When it’s set to 0%, it will only play the voices once. If it’s set to 100%, it will keep repeating the voices indefinitely.

The Snapshots feature allows you to load up settings you may want to recall. There are 32 of these snapshots available, and they let you switch between settings on the fly. I think of it as a type of “favorites” for loading up different settings, similar to selecting a preset. One advantage is that you don’t have to skim though the presets in the browser. This is a feature that is also found in a few of the other Eventide plugins, such as the UltraReverb and H3000 Band Delays. It’s included in some of their hardware products as well.



I think by now that you may realize how very powerful this plugin can be. You might only use this on a single track in your project, but you could also load it into multiple effect sends in your DAW. Each of those instances could be setup with different tunings and/or delay settings, and you can mix and match and/or layer them to your liking.

Quadravox is a very useful plugin, and experimenting with its many timings and tunings can be lot of fun. It retails for $99 USD and it is also part of their Anthology X bundle and Ensemble Subscription. Eventide has another product called Octavox which has the same features, but it has a total of eight voices available. Octavox retails for $199 USD.

For more information or to purchase, click the link below:

Quadravox is also available from numerous other music-technology retailers.


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