Your browser is out-of-date!

Update your browser to view this website correctly. Update my browser now


TC Helicon VoicePrism Plus Vocal Processor

TC Helicon is a collaboration between TC Electronic of Denmark and IVL Technologies of Canada. TC Electronic's expertise in DSP wizardry is known worldwide; lesser-known IVL pioneered vocal pitch processing with Digitech's near-vintage Vocalist range.

TC Helicon is a collaboration between TC Electronic of Denmark and IVL Technologies of Canada. TC Electronic’s expertise in DSP wizardry is known worldwide; lesser-known IVL pioneered vocal pitch processing with Digitech’s near-vintage Vocalist range. The VoicePrism Plus vocal channel, intelligent four-part harmony generator and dual effects processor is the prodigal child of this successful pairing.
Product PointsApplications: Studio, live sound

Key Features: 44.1 kHz, 48 kHz sample rates, 48V phantom poweredmic preamp, numerous voice manipulation effects, onboard digital processor effects, compressor

Price: $1,898

Contact: TC Helicon at 805-373-1828, Web Site

VoicePrism Plus ($1,898) is the updated version of the ground-breaking VoicePrism processor; the “Plus” indicates the addition of the Voicecraft card. The Voicecraft card is available separately ($599) to update the earlier VoicePrism model.

The VoicePrism Plus’ two-rack-space case has an angled front panel featuring a large LCD display, a data wheel for scrolling through presets and five dedicated buttons for browsing settings categories (shift, scale, manual, chord and effects). Four soft knobs below the display adjust various on-screen parameters. Additional edit buttons are used to access the individual sections of the processor (vocals, effects, comp/EQ, mix and Step). Input meters and a large numerical preset display are incorporated on the left side of the LCD screen.

Also on the front panel is a section for levels and utility functions which includes individual knobs for input, lead voice, harmony voices and effects levels. Additional buttons in this section control effect bypass, utility options, phantom power, help menus and preset management functions. An XLR for microphone input and a 1/4-inch stereo jack and level knob for headphones complete the front panel.

Connections on the rear panel include a single TRS 1/4-inch line in jack, a TRS 1/4-inch aux in jack (for input to the effects section only), and two TRS 1/4-inch line outputs. The new Voicecraft card adds digital I/O on XLRs for AES and phono jacks for S/PDIF (full 24-bit) and changes the function of original S/PDIF output-only jack to provide access to the unprocessed mic/line (left) and aux (right) inputs – a nice touch. The unit operates at 44.1 kHz or 48 kHz internally, syncs to incoming digital audio and can dither its 24-bit output to 20, 16 or 8 bits.

A +4dBu/-10dBV input level switch, standard fuse-loaded IEC A/C jack, MIDI in/out/thru and a 1/4-inch footswitch jack for stepping through presets complete the back panel.

In use

The first item displayed upon powering up the VoicePrism Plus is the Preset screen. This general display shows the most important information about the preset in use, including key, harmony mode, scale type and number and type of harmony parts. Occasionally hilarious human head icons represent the gender and type of formant shifting for each the harmony parts (up to four) in the chosen preset. Other amusing head icons are available at the TC Helicon website ( The preset screen also displays the basics of the compressor, equalizer and dual effects sections.

The functions of the four soft knobs change depending on the preset selected and usually represent the most frequently needed functions. Pushing in on the soft knob conveniently opens up a drop-down list of other functions that can be assigned to the soft knobs.

The aforementioned edit buttons access a set of layered parameter screens for fine- tuning the selected function. The first edit button, for example, is for adjusting Vocals and then navigating to the Harmony tab brings up four faces illustrating the gender of the backing parts. Using the soft knobs, it’s possible to change the level, pan, gender and voicing of each part, and, as the gender value is changed, the little face icon morphs through its repertoire of facial types.

The new Voicecraft board adds vocal modeling based on studies and samples of many different voice types. The subject of voice modeling and the technology implemented here could fill this whole magazine; fascinating stuff, but it’ll have to wait for the PAR “Vocal Formant Synthesis and Glottal Analysis Issue.” In brief, the near real time (surprisingly little delay) process maps formants and glottal sounds of the chosen voice type to those of the inputted voice. Additional adjustments for initial pitch-ins and vibrato modulation are based on the complex characteristics of actual voices.

On to the important bit: how does it sound? Let me start off by saying the TC reverbs and choruses within the dual effects processors are almost worth the street price on their own. Add in the vocal channel provisions (quality mic pre, compressor and EQ) and, of course, the powerful capabilities that define the main purpose of the box – vocal modeling and harmonies – and this versatile production tool is a bargain.

I found, like most audio processors and effects units, the VoicePrism Plus has the potential to be used for good or evil. In the wrong hands, over- or improper use of any processor can result in aural atrocities; the potential increases with the Grail-like nature of the VoicePrism Plus.

So let me start by bursting some bubbles: no, you can’t input Bob Dylan’s “voice like sand and glue” (to quote “Song for Dylan” by David Bowie) and output Vince Gill… thank God. But with realistic expectations and some finesse, this box can create tasteful effects, fatten up lead vocals and add depth and life to layered harmonies.

I successfully used the VoicePrism Plus to do all of the above, and was impressed with the results. The trick is to start with decent tracks and know the limitations of what can and cannot be accomplished with this powerful tool.

I found that one of the best applications of the VoicePrism Plus was to use its harmony and vocal emulation capabilities to improve the otherwise “incestuous” sound that results when one person performs all the parts of a layered harmony (think Enya’s “Sail Away”). As a recording artist as well as a recording engineer/producer, I often find myself in that exact situation, simply for the lack of proximate warm bodies who can sing. I mean, where are all the singers at four A.M. when you need them most?

The ability to fold in qualities of other male and/or female voices along with my own -complete with subtle timing, pitch and vibrato variations – quickly transformed a track I was working on from that “hey, look at me…I sang all the parts” sound to one that sounds very ensemble-like.

Again, it took some restraint and experimentation to reach the level of understanding necessary to produce results that sit imperceptibly in the mix.

Thankfully, TC includes lots of great presets with which to get started. These range from simple lead vocal thickening programs to full ensemble harmonies to truly bizarre effects. Experimenting with the presets and their respective settings for a few hours shortened the learning curve considerably. TC also includes an online context-sensitive help system, accessible via a dedicated button on the front panel – definitely a nice touch.

My one wish for the VoicePrism Plus is that its XLR microphone input be located or duplicated on the back panel. Though not a major complaint, it is a bit inconvenient (and unattractive) for typical studio installations where existing mic runs terminate at the back of the rack; I cannot imagine the frontal location is that much more useful in live applications either.


After spending some quality time experimenting, you can’t help but learn the ways of VoicePrism Plus. Use that knowledge for good, not evil; the VoicePrism Plus will reward you with many voices of experience (and their relative harmonies).

The bottom line? When provided with decent source vocals and used with care, it is easy to see the VoicePrism Plus becoming an essential tool for many recording engineers and producers.


Westlake 8.1, Mackie HR824 and TripleP Pyramid studio monitors; Hafler H3000 power amplifiers; Digidesign Pro Tools MixPlus workstation; Zaolla Silverline analog and digital cables