Metric Halo Channel Strip Manual
Alfie Overacre
The most obvious reason for using channel strip plug-ins is to free up insert points. There is a brick-wall limit of five insert points on each track in Pro Tools, and you can quite quickly fill them up with routine plug-ins. For example, on a vocal track you might have an EQ followed by a pitch-correction plug-in, compressor, de-esser and reverb or delay. If you then wanted to add, say, a treble enhancer or an ADT effect, you'd find all your plug-in slots already used up. A channel strip plug-in that combined at least some of these functions would free up some insert points.
Another potential advantage is that having one plug-in window covering all the channel strip functions would help to simplify and streamline our workflow, compared with having five plug-in windows open simultaneously to manage and make adjustments on all these separate plug-ins.
The figure for internal bit depth shows what the internal headroom of each plug-in will be like, where that information is available: some manufacturers have not published information on this. Remember that you still need to watch your level architecture even with double-precision plug-ins, as although the plug-in may be able to handle the extra level, you may experience headroom problems once it gets out.
To test each plug-in's sound quality, functionality and ease of use I took an existing vocal track which already had all five insert points in use. I then used each channel strip plug-in in turn and tried to replace at least the EQ and compressor in such a way that I could reproduce the same sound, or even maybe improve on it. The vocal in question has a wide dynamic range that will test the compressor sections well, and the original sound needed warming and brightening, hence the requirement for EQ.
One of the obvious benefits of a channel strip plug-in is that you have control over your EQ, gate and compressor from within a single window. However, to keep the graphical user interface (GUI) sensible, a number of the manufacturers have chosen to make compromises such as losing the graphical displays of the EQ and/or dynamics sections. Providing there is good dynamics metering telling me what is going on in the dynamics section, I would prefer to lose the dynamics display, as a graphical display of the EQ curve is a lot more useful.
The plug-ins also vary as to whether they include side-chain EQ. While this is a helpful feature, it isn't a deal-breaker for me, as the most frequent use of side-chain EQ is for de-essing, and to do that properly you need a proper de-esser with a frequency-selective side-chain and signal path.
Renaissance Channel (right) comes as part of Waves' Renaissance Maxx bundle and is a combination of the four-band Renaissance EQ and either Renaissance Compressor or Renaissance Vox as the dynamics section of the channel. In line with the rest of the Renaissance range, Renaissance Channel 's internal audio path is 48-bit; this gives 18dB of internal headroom, allowing you to make significant EQ boosts without causing overloads within the plug-in. The dynamics section offers a gate/expander as well as the choice of compressors. There are single-band EQ sections in both the compressor and gate side-chains, and the EQ graph can show these as well. It is also possible to switch the compressor before or after the EQ section. Finally, there is a Clip Guard Limiter, which will limit the channel output to 0dBFS, to protect the subsequent audio chain from the higher levels achievable within the Renaissance plug-in. The meters in the bottom left-hand corner are not input and output level meters. They are actually Energy Meters and display the energy in the two side-chain paths, which I find a very helpful indicator of what is actually hitting the side-chain.
This plug-in combines the great sound of the Waves Renaissance plug-ins, and as the reference track used a six-band Renaissance EQ and a Renaissance Vox compressor I was able to quickly and easily replace the two plug-ins with the one channel strip. The Waves Renaissance plug-ins are my usual first port of call for EQ, compression and de-essing, so it will come as no surprise that I liked this plug-in too.
This plug-in (below) is a treat for all those SSL fans who can't afford to buy the real thing or who want to mix in the box and have the SSL sound that has become so popular in certain circles. This plug-in is part of the Waves SL4000 bundle and is modelled on the SL4000 E-series console, combining the channel strip dynamics section with the Black Knob 242 EQ. The dynamics section is described as a soft-knee compressor/limiter and an expander/gate. I have to say that my definition of an expander is a gate with a ratio control to adjust the rate of expansion: this plug-in doesn't have one, so for me, this should be described as a gate section.
The EQ element has a four-band parametric section, as well as two filters. The routing options are comprehensive, enabling the user to have both the EQ and filters in the main path, or split the EQ section so the filters come before the dynamics and the parametric EQ after the dynamics. Alternatively, you can have the main EQ section in the channel path with the filters in the side-chain, or the filters in the main path and the EQ in the side-chain, or both the filters and the EQ in the side-chain. I found I needed to refer to the flow charts in the manual to establish the correct combinations of the Split, Ch-Out and Dyn S-C buttons to achieve these routings, as I didn't find the buttons particularly intuitive.
The other interesting button on this plug-in is the Analogue on/off switch. The manual describes this as emulating the noise and distortion found in the analogue hardware, and argues that this is part of the desired sound. The default setting for this switch is on.
I have never been a great SSL fan, but once I got past the complete lack of a graphical display and set to work on this channel strip, I was very impressed with the sound. It handled dynamics well, and the general sound was very open, not sounding squashed even though the compressor was working hard.
The next two plug-ins come as part of Eventide's Anthology II bundle, which we reviewed in the July 2006 issue of SOS. E-Channel (above) is designed to be DSP efficient, and as you can see from the chart on the previous pages, you can get six of these onto one HD DSP chip. This channel strip includes a gate, a compressor/limiter and a five-band parametric EQ section. I liked the way the display includes different-coloured frequency plot curves showing what each band is doing, as well as the usual strong line that shows the composite frequency plot. One minor drawback is that there isn't a stereo version of this plug-in so you will need to use multi-mono versions on your stereo tracks. I was surprised at how good these plug-ins are, as you don't normally associate Eventide with channel strips. It took me a little longer to get a good sound than with some of the others, especially in dealing with the wide dynamics of the source, but once I had adjusted the compressor's attack and release times, the sound I was looking for fell into place. The wide range of EQ shapes proved very useful in getting the warm and bright sound I was looking for.
This channel strip (top right) includes a gate, de-esser, compressor/limiter with side-chain, Omnipressor compressor, a five-band parametric EQ section, stereo delays and a Harmonizer micro-pitch-shifter for thickening. All the modules in both Eventide channel strip plug-ins, except for the Harmonizer and stereo delays, can be re-ordered by dragging and dropping. I liked Ultra Channel on solo vocals, especially with a dash of Harmonizer thickening. On the down side, Ultra Channel is the most DSP-hungry plug-in on test, with one instance taking a complete HD chip.
The de-esser didn't do it for me: I couldn't get the vocal clean of sibilance without messing up the sound, so I found myself reaching for my preferred de-esser again. I am disappointed that the Eventide plug-ins are TDM-only, with no Audiosuite versions, and I found the frequency limits on the EQ sections a nuisance. I can understand why these restrictions exist in genuine analogue designs, but on digital EQs there surely should be no reason why every band can't be adjusted across the full frequency range.
Once I had given up on the de-esser section I was very quickly able to get a good sound, and the benefit of the Omnipressor showed itself in handling the dynamic range. A dash of the micro-pitch-shift added a unique additional touch to the sound.
On Aux and Instrument tracks, adding only RTAS plug-ins costs you one extra voice, but adding an RTAS plug-in after a TDM one on these tracks will cost you yet another voice. Inserting only RTAS plug-ins on a mono master track uses two extra voices; on a stereo master, it costs you four voices, and once you move into 5.1, voices get eaten up at a rate of knots.
So beware: always try to put your RTAS plug-ins before your TDM ones, and try to only use TDM plug-ins on Aux, Instrument and Master tracks if you want to maintain your voice count for tracking and so on. This is especially important when you're using Quick Punch and Track Punch (see last month's Pro Tools workshop for more), which require an extra voice for every record-enabled track. You have been warned!
Contrary to popular opinion, McDSP's Channel G (below) is not an amalgam of their Filter Bank and Compressor Bank plug-ins (see the review of their Classic Pack elsewhere in this issue) but is, as they describe it, "a new plug-in from the ground up", with new algorithms. However, like their other popular plug-ins, it emulates a range of vintage EQs and compressors from the likes of Neve, Amek, API and SSL. McDSP point out that these presets are inspired by these classic consoles, rather than being exact copies of them, but if you cannot afford the Waves SSL channel strip, Channel G includes SSL E-series emulations which might provide an alternative.
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