Focusrite Platinum Voicemaster

It's a Focusrite, Jim, but not as we know it! Is it possible to deliver Focusrite quality at such an aggressively low price?

Last month's issue was the first time I'd reviewed a Focusrite Platinum processor and their ToneFactory delivered far more than I expected for the price (see SOS June '98). If anything, the Platinum VoiceMaster goes even further. Housed in the same 1U, silver‑fronted rack case as the ToneFactory, the VoiceMaster is designed primarily for processing microphone signals, although it also includes a line level input for other instruments.

This type of product is gaining popularity both as a front end for hard disk recording systems and for use in conventional studios, where bypassing the mixer during recording helps maintain a cleaner signal path. Here, the mic amp is followed first by an expander/gate, then by a very effective saturation circuit for creating valve‑like sounds, then an opto‑compressor, then a comprehensive EQ section fine‑tuned for vocal use, and finally a sophisticated opto (photo‑resistor) de‑esser.

A Flexible Friend

To ensure that the unit is as flexible as possible for recording and mixing, rear panel connections comprise XLR mic and balanced jack line inputs, an insert point, and a further line out on a balanced XLR prior to the de‑esser. As there is no high impedance instrument input on this model, guitarists will need a DI box or active pickups. The main line out is available both on a balanced XLR at +4dBu and a regular unbalanced jack at ‑10dBu. Having an output before the de‑esser can be useful when you want to keep the main vocal sound unprocessed, but at the same time feed a de‑essed version to a bright reverb.

At the input is a discrete Class A mic/line circuit with up to 60dB of mic gain and a creditably low, quoted equivalent input noise (EIN) of ‑128dB with a 150Ω source impedance. (Focusrite provided Audio Precision test set measurements to back up their specification claims.) Also quite staggering is the audio bandwidth, which reaches up to 200kHz (‑1dB) — around 10 times higher than the limit of human hearing. Wide bandwidth is one of the factors that preserves audio transparency in high‑end audio equipment. The mic amps' common mode rejection of interference from balanced sources is also particularly good.

Rather than simply provide a switchable low‑cut filter, the 12dB/octave high‑pass filter has a variable frequency (20Hz to 300Hz), complete with switchable phantom power, a phase switch, a line switch and a bypass button for the high‑pass filter. All individual sections of the unit have their own bypass buttons, each with an integral red status LED. A simple two LED system shows green when healthy signals are present and red when they're getting too close to clipping.

Directly after the preamp comes an expander/gate with Threshold and Depth controls. Threshold sets the level below which the signal will be subjected to gain reduction and Depth sets the severity of the gain reduction. In Expander mode, the gain reduction ratio is varied by the Depth control, whereas in Gate mode, the signal is attenuated when it falls below the threshold level, with Depth acting as an attenuation amount control. There is no release control, but, in practice, the expander is so smooth and well behaved that unless you're after a deliberately gated sound, it's probably best to stay in Expander mode. A four LED meter shows gain reduction and the Bypass button switches the Expander/Gate out when it's not needed.

After this very pure front end comes the Vocal Saturator, an FET‑based soft clipping circuit that behaves not unlike an overdriven valve, though the effect is quite subtle compared with the ToneFactory unit. It can be used full bandwidth or confined to frequencies above the value set on the Tuning knob, which controls a band filter variable between 1kHz and 7.2kHz. When the Full Bandwidth button is in, the filter is switched out, allowing full‑band processing to take place.

This whole section works surprisingly well. I'm generally quite sceptical about 'warmth' circuits, but with the Tuning control set to the halfway point or above, a sparing application of the Drive control brings in a very nice sounding high‑end enhancement reminiscent of a stand‑alone exciter type of product. Bypass takes the section completely out of circuit, so purists don't have to worry about having distortion added when they don't want it.

Not only does the unit have a quiet, transparent and very classy sound , it also behaves very smoothly and predictably, which is worth a lot to the recording musician.

Compress To Impress

The compressor section is based on the dual opto circuit used in Focusrite's new ToneFactory, but tweaked to make it more suitable for vocal use. Ratio is only switchable between Normal and Hard, while Attack may be switched to Normal or Fast settings. Variable controls are provided for Threshold, Release and Output level, but there's an extra knob labelled Treble. This isn't a regular tone control, but rather a type of dynamic equaliser that works by EQing the difference signal produced by subtracting the compressed and uncompressed sounds, then adding this EQed sound back into the compressed signal. The more gain reduction is applied, the larger the contribution of the EQed component. Treble may be used to counteract the slight dulling that can occur when signals are heavily compressed and the result is not unlike a dynamic EQ type of enhancer — subjectively quite different from the harmonic enhancement created by the Vocal Saturator. A six LED meter shows the amount of gain reduction being applied during compression, and of course there's a Bypass button.

Following on from the compressor is a smooth sounding 3‑band EQ with slopes optimised for vocals. Instead of calling the controls bass, middle and treble, they're named so as to provide some indication of how they might sound on vocals. Warmth controls the low end of the voice and has a separate tuning control covering 120Hz to 600Hz with a moderate +8/‑12dB gain range. Both Warmth and Presence have bandpass or bell responses. Presence looks after the 1.5kHz range, while Breath controls the 10kHz‑plus region of the spectrum using a shelving response. No section offers more than 8dB of gain as the EQ is designed for fine tweaking and polishing, not for total reshaping, but even so it seems to have plenty of range. To prove the designers have a sense of humour, there's a further button named Absence below the Presence control. The idea is to place a 4kHz notch in the spectrum to help smooth out those singers who have problems with vocal roughness (apparently this setting is optimised for female singers!).

The final process in the chain is a de‑esser, again arranged around an opto gain cell and with a red warning LED to show when it's applying gain reduction. Unlike simple de‑essers based on compressor circuitry that duck the whole signal level when sibilant sounds trigger the process, there's a Cut Frequency control that can be varied between 2.2kHz and 9.2kHz. When a signal exceeds the threshold set by the user, only the band of frequencies around the value set on the Cut Frequency control is attenuated. As I understand it, the circuit detects the sibilant sound, then adds it back to the original sound out‑of‑phase, causing it to cancel out. Treating only the sibilant part of the audio spectrum effectively avoids the sound becoming dull during de‑essing, and also stops the unnatural lisping effect that full‑band de‑essers tend to cause. The de‑esser can be bypassed when not required, which leaves only the Master Fader output level control and its associated six LED level meter. Strangely, the mains power switch is not illuminated, so if all the sections are bypassed and no signal is present, nothing will be lit up.

Testing The Master

To produce six different Focusrite quality functions for just £379 is quite an achievement. Of course, you're not getting the same circuitry as you find in the Focusrite Red range, or even their Green range — that would be financially impossible. But the Focusrite engineers have shown that it's possible to take carefully chosen standard components and incorporate them into well‑designed circuits in such as way as to produce results that are several cuts above the ordinary.

The Platinum range is aimed at musicians. Focusrite describe the units as "results orientated", which is why the EQ controls are named after their effect rather than their place in the audio spectrum. Similarly, the artificial warmth generating circuitry would be quite out of place in a high‑end professional mic preamp, but for the musician who wants more control over the results, it's a great idea.

Not only does the unit have a quiet, transparent and very classy sound (if that's what you set it to do), it also behaves very smoothly and predictably, which is worth a lot to the recording musician. For example, the expander is about as smooth as I've ever heard — you just set the threshold, then increase the depth until the low‑level signal has been attenuated to an acceptable degree. Similarly, the de‑esser manages to make a significant improvement to vocals afflicted with over‑pronounced 'S' and 'T' sounds. If you push it hard, you can just about hear it working, but you really have to work hard to spoil a sound with the VoiceMaster unit. I also found the de‑esser good for removing sibilants over‑emphasised by the various enhancement and EQ options provided by the unit. Switching in either the saturator or de‑esser with their controls set for minimum effect causes a very slight level rise, which sometimes makes it difficult to judge exactly what effect you're getting, as louder signals always sound more impressive. It pays to be aware of this.

Like the compressor in the ToneFactory I reviewed last month, this one is flexible enough for most jobs yet very easy to use. Both the mic amp and compressor have an open, transparent sound, though the compressor starts to become more obvious if much more than 10dB to 12dB of gain reduction is applied. The equaliser is quite ingenious in that it gives you control over the key areas of the human voice without you having to know much about EQ. I was particularly impressed with the Warmth and Breath controls. Where corners have been cut, it's been at the expense of in‑depth parameter twiddling or metering rather than sound quality. The VoiceMaster provides the tools to create a pure vocal or a creatively enhanced one. I think the only problem Focusrite are going to have is making enough of the things!