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 | | | | Dec31Written by:Rip Rowan
Thursday, December 31, 1998 6:00 PM  This shootout has been a long time coming and even a longer time waiting. I won't pretend that it isn't way overdue, so my apologies go out to everyone that's waited for it.
Nevertheless, it's here! We're throwing a handful of the top of the line DirectX dynamics processors into the mix and seeing how they stack up. We're going to use and abuse each one of them. In the end, we will present a rating from 1 to 10 in terms of sound quality, ease of use, features, processor efficiency and an overall rating. Rather than presenting the overall rating as a composite of the other three categories, the overall rating will be this reviewer's subjective rating of the relative need-to-have factor.
Note this is the third article in a series on compression. If you didn't read Part One or Part Two, you ought to go back and check them out.
About the Evaluation
The processors were evaluated in real-world conditions. Each one was used to process acoustic and electric guitars, bass, drums, vocals, and entire mixes. The tools are evaluated using Cakewalk Pro Audio 8.01 and Sound Forge 4.0. We went for both "unprocessed" sounds (using the processor to control the dynamics with as little as possible audible alteration to the sound) as well as "squished" effects where we dialed in some heavy compression to hear how the plug-in altered the sound when driven hard. In most cases I have used these processors in heavy actual practice and I am intimately familiar with all of them.
Evaluating compressors is mightily subjective. We are all aware of the resurgence of vintage compression technology using optocompressors and tubes to generate that warm smooth sound of famous vintage units. So, what does it mean to say that a compressor sounds good? I consider a compressor to sound good if (1) it leaves the sound as uncolored as possible, or (2) if it imparts some kind of coloration that in my opinion is a valuable color. In any case, when I say I like or don't like the sound of a particular unit, I'll tell you why.
Overall impressions were favorable. Digital compressors have a sound of their own: none. That's not exactly true, but the worst compressor in this review is as good as any $500 compressor you're going to find anywhere (with one exception - the RNC Compressor). The best software compressor is as good as any hardware compressor you've ever heard. And if your goal is deep compression with the least harmonic distortion, or signal-level maximization, then digital's the only way to go.
So let's get down to business.
Hyperprism Compressor / Limiter / Gate
Available in Hyperprism 1.5.5
The Hyperprism dynamics processors are available as part of Arboretum's Hyperprism 1.5.5 effects package (reviewed in its entirety this month). This is a comprehensive effect package that offers a wide variety of cool processors, including a great reverb, delays, EQs, compressors, a vocoder, HF and LF "enhancers", distortion processors, pitch and frequency shifting, and more.
There are 3 different dynamics plugins: Compressor, Limiter, and Noise Gate. Each makes use of the ubiquitous Hyperprism Blue Window, a 2D programmable "joystick" that allows you to assign effect parameters to the X or Y axis of the joystick - the stick could control Gain (X) and Threshold (Y), for example, or Attack and Release, or all four, if you want.
 Hyperprism DX Compressor
The Compressor plug-in offers the basic Compression features: Input and Gain Reduction meters, Ratio, Threshold, Attack, Release, and Makeup Gain. The compressor offers no sidechain. The Limiter similarly offers the usual features: Threshold (called Ceiling), Release, and Volume (Gain) along with Input and Gain Reduction meters. Finally the Noise Gate offers an Input Meter, Threshold, Attack, and Release controls. Online help is available which describes the function of each control.
Pros
These plugins are the most processor-efficient of the bunch, with CPU usage of 2-3% as measured in Sound Forge 4.0. In the resource-constrained world of DirectX, that's a nice advantage. On my system I was able to run 8 compressors, 2 limiters and a noise gate in real-time on a 16 track mix with no obvious strain on my CPU. I'm sure there was horsepower available for lots more.
Cons
These are plain-Jane plugins. While their simplicity contributed to the positive "processor efficiency" score, it negatively impacts other aspects. The knee is not variable, and to my ears is a hard-knee process (it doesn't say in the online help). There is no sidechain, which means you cannot use these processors for de-essing. There is no output meter or clipping indicator or output level meter. And there is no Expander option available.
Overall sound quality is the poorest in the bunch. Which is not horrible - the quality is in fact good compared to averaged-priced rack mount gear. But there are several problems with the sound quality.
One problem is the lack of a soft knee. The Noise Gate immediately opens and closes with no gentle fade, and the limiter and compressor engage suddenly. Although each unit offers attack times of 0, there is no lookahead function, which means that sudden peaks are simply clipped and not "soft-limited" by softening the transient. The limiter, when driven hard, seems to clip the output too hard, resulting in blurred treble on a 2-track final mix.
I also have to weigh in with mixed feelings about the Blue Window. I love new ideas. So, on the one hand, I applaud Arboretum for this user interface innovation. In fact, overall, the Hyperprism-DX package is the most innovative and comprehensive DirectX package available, with lots of cool effects like Vocoder, Frequency and Pitch Shifters, and others. The Blue Window is a great innovation and I hope that Arboretum retains its functionality.
However, when I'm compressing, I need a different interface than when I'm adding reverb, and when I'm EQing, I need a different interface than when I'm limiting. Unfortunately, although it is innovative, the Blue Window does not add value to the dynamics plugins. Form should follow function, and for that reason the user interface falls short. Suggestion to Arboretum: customize the interfaces to suit the particular application. Then provide the Blue Window as an OPTIONAL, hideable control.
Summary
Although I like the Hyperprism package overall, and will continue to recommend it, the dynamics processors are pretty minimalistic, and are inadequate for mastering. If you don't already own a plug-in package, then Hyperprism is a great place to start. It will give you a killer variety of usable plugins for one reasonable price. If, however, you are looking for THE dynamics processing tools to add to your existing suite of plug-ins, read on.
Sound Quality:..............7.0
Ease of Use:................7.0
Processor Efficiency:.......9.0
Abundance of Cool Features:.6.5
Overall:....................7.5
Cakewalk FX-1
Dynamics Processing Package
Cakewalk's first foray into the world of Direct-X plugins is FX-1, a set of four dynamics processors: Compressor / Gate, Expander / Gate, Limiter, and Dynamics Processor, a multifunction processor incorporating Compression / Gate / Expansion / Limiting and some other nifty dynamics processing options.
Like most digital dynamics processors, the Cakewalk processor incorporates a transfer function graph into the user interface. The user has the option of controlling the processor using knobs, by directly entering numbers, or manipulating handles on the transfer function graph. I like transfer function graphs and find them to be an intuitive user interface for digital dynamics processing.
 Cakewalk Dynamics Processor
Each plugin offers all the controls you'd expect to find on a dynamics tool: Input and Gain Reduction meters, Ratio, Threshold, Attack, Release, and Gain. Additional options include a sidechain, peak / average / RMS detection, and stereo link switches. Additionally each Threshold control offers an "in" light that informs the user when the threshold has been crossed.
Pros
I like Cakewalk's implementation of the transfer function graph. The graph lets you grab the graph handles and drag them into appropriate settings to control the unit's parameters. On the three "standard" units (Compressor / Gate, Expander / Gate, and Limiter) the graph allows you to control only Threshold and Ratio settings. However, using the multifunction Dynamics Processor, you can add up to 9 extra nodes to create dramatic or bizarre transfer functions (see photo).
This feature can really let you design some soft knees and truly variable compression and gating. For example, you can apply a noise gate below -50 db, an expander from -50 db to -30 db, 1:1 from -30 to -20 db, 2:1 from -20 db to -12 db, 5:1 from -12 db to -3 db, and a limiter above -3 db. Using similar settings I was able to arrive at some wonderful vocal tracks in particular: the noise floor was eliminated, semi-audible noises were damped but still present, the lower-volume phrases were slightly compressed, the louder passages were heavily compressed, and peaks were held below clipping with the limiter. That's a lot of control and some of the most flexible dynamics control available from any single plug-in compared in this review.
The sound quality was very good. I especially liked the soft knee used in this compressor. When using the multifunction Dynamics Processor, such as the setup described above, the sound quality was outstanding. Used in this manner you can really heap on a lot of compression with a minimum of sonic artifacts.
The feature set was robust. The incorporation of a sidechain and optional stereo link gave FX-1 all the flexibility you'd expect from a good hardware unit. And Cakewalk did a good job of providing the "essential" compressor packages you typically use - Compressor / Gate, Expander / Gate, Limiter, and multifunction Dynamics Processor.
I also like the option of choosing the detection algorithm: Peak, Average, or RMS. Peak detection is useful primarily for limiting, whereas Average and RMS detection are better suited for vocal and instrumental compression. The inclusion of such advanced features really make this tool well-suited for professional use as either track inserts or overall mix compression / limiting.
Cons
Although it is a strong offering, this package does have some minor drawbacks, primarily in the area of user interface. The metering is poor. Why, oh why would a software company simulate the 8-LED meters available only on the lowest-end hardware units? I would like to see continuously variable meters, not the 8-LED simulation provided. And there's no clipping indicator or output level meter. These are very useful - almost required - when setting makeup gain.
CPU utilization was average: 9-12% in SoundForge 4.0. I would have liked to see a stripped-down compressor-only utility (this is what we usually use on the inserts anyway) that achieved better performance numbers.
I did not like the fact that there is only one set of attack and release controls for the unit. These controls control both the compressor and the gate. Personally, I don't use a lot of noise gating. Spurious noise, like breathing, fretting and fingering instruments adds to the nuance of a good recording. Hiss and hum and other background noise can be eliminated with better mics, better mic techniques or a better room. However, when I do use a noise gate, I want to be able to control the attack and release of the gate independent of the compressor or expander.
Finally, and maybe this is just me, I don't like the knobs used on the interface. I understand the use of knobs versus sliders: knobs are smaller and screen real estate is critical. The problem is not the use of knobs - it's the kind of knobs: they're round, with black lines to indicate their position. It's hard at a glance to see the settings. Next time, use the chicken-head knobs.
Summary
These are good processors with an eye towards professional mixing applications. Their sound quality is good and their flexibility is good. The multifunction dynamics processor in particular is unique among these plugins and a great tool to own. If you have effect plug-ins and are looking for a good dynamics processor to add to your arsenal, these are the lowest-cost way of getting into some professional-quality compression. I give these tools the thumbs-up.
Sound Quality:..............9.0
Ease of Use:................8.0
Processor Efficiency:.......8.0
Abundance of Cool Features:.8.5
Overall:....................8.5
Sonic Foundry Graphic Dynamics
Available in Sonic Foundry XFX-2 Package
Graphic Dynamics is a simple Compressor / Limiter from Sonic Foundry. The tool is controlled with a large transfer function graph and a few simple controls. The unit does not have a built-in soft knee, but the user may add as many points as desired to the transfer function as needed to soften the knee. Only the standard threshold, ratio, gain, attack and release controls are provided. An auto-gain makeup is provided to automatically set the output gain to maximize the output level.
 Sonic Foundry Graphic Dynamics
Pros
This is a no-frills compressor that gets the job done. Most notable is the excellent performance of the tool, offering CPU utilization of 3-4%, placing it in the range of Hyperprism's plugin. The tool utilizes an editable transfer function, like the Cakewalk Dynamics Processor. Therefore, combinations of gates, compressors and expanders can be easily created.
Sound quality falls somewhere between the Hyperprism and Cakewalk compressors: very good. Combined with the excellent processor efficiency and the ability to create complex transfer functions, Graphic Dynamics may be the perfect tool to use as a track insert for non-critical tracks.
Cons
Two things are painfully lacking in this unit.
The first is meters. There are no meters at all. This is just not acceptable to me. I find metering to be a necessary function of a compressor.
Secondly, there is no soft knee available. Although you can soften the knee by adding more points to the transfer curve, it does not provide the graceful knee I like to hear on a good compressor.
Summary
Plain and simple, this is a practical, efficient processor. I would not recommend it for mastering, but it's an excellent track insert on a multitrack mix. I did not like the auto-gain control. I prefer to set the gain myself - but I'd like some meters to help me do it!
Sound Quality:..............8.0
Ease of Use:................8.5
Processor Efficiency:.......9.0
Abundance of Cool Features:.6.5
Overall:....................8.0
Sonic Foundry Multi-Band Dynamics
Available in Sonic Foundry XFX-2 Package
Sonic Foundry Multi-Band Dynamics is a four-band compressor-limiter. Each band is independently controlled and may be switched in or out to conserve processor cycles. The bands are sweepable from 50 to 15KHz and their width is adjustable from .3 to 3 octaves. The bands offer selectable low shelf, peak, or high shelf curves The standard controls are provided for each band: threshold, ratio, gain, attack, release. The unit also provides a "capture threshold" control which automatically finds the threshold of each band selected.
 Sonic Foundry Multi Band Dynamics
If you've never used a multiband compressor before, look out. A multiband compressor can completely change the sound of instruments in the mix. For example, I used Multiband Dynamics on an acid jazz number that had an overly ringy snare.
First, without engaging the compressor, I turned the gain up and swept the frequency until I had found the ring. Then I used the auto threshold to find the threshold of that particular frequency. Now I engaged a 4:1 compressor, and s-l-o-w-l-y brought down the threshold. After I had lowered the threshold about one db the sound of the snare had totally changed to one that was very smooth and natural. The rest of the track was unaltered. I brought the level down about another 2-3 dbs and instantly screwed the track up: the music hollowed out, the snare completely changed to a totally different and bad sound, and it lost its punch.
Extreme settings are almost guaranteed to be bad.
Pros
This is the only tool in this roundup that provides multiband dynamics control over more than one band at a time. It can be effectively used in mastering applications to control harsh frequencies that sometimes seem to suddenly jump out in a mix. It can also be used on a track for applications such as de-essing and bass volume leveling.
I especially like the ability to automatically find threshold levels. Since this tool is used as a dynamic equalizer, the automatic threshold makes it very easy to find a good starting point and then nudge up or down as needed.
Processor efficiency is very good, running about 6% for one band of dynamics control up to 16% for all four bands. This fares very favorably to the Waves C1+ which offers only one band of control and consumes about 16% (without IDR, see below).
And, hats off to Sonic Foundry for creating a user-friendly interface with appropriately labeled controls. Like the Sonic Foundry EQ, the Multiband Dynamics does not have a Q control. Instead, EQ width is labelled in octaves. Thank you, thank you, thank you.
Cons
There are a few features that would have been nice to have. I would have liked to have a lookahead function. Whenever I do digital peak limiting, I like for the limiter to be able to soft-clip transients instead of the usual hard-clip. Soft clipping, availalbe with units that offer lookahead, creates smoother, more natural sounding transients.
Summary
This is a unique tool in this roundup. Although it can be used as a track insert, this processor's niche is in mastering. The Sonic Foundry Multi-Band Dynamics processor is a must-have for anybody who wants to do professional quality mastering. Only a good multiband compressor can change the EQ of individual instruments in a mix, and this one does it well.
Sound Quality:..............9.0
Ease of Use:................8.5
Processor Efficiency:.......9.0
Abundance of Cool Features:.8.5
Overall:....................8.8
Waves C1+
Waves L1+
Available in Waves Native Power Pack
Waves C1+ and L1+ are available as part of Waves' popular Native Power Pack. For a full review of the entire Native Power Pack, read Pete Leoni's review.
The Waves C1+ is a family of DirectX plugins for dynamics processing. There are several flavors of C1+, depending on the functions you need:
1. Compressor (C1 Compressor)
2. Compressor w/ sidechain (C1 / Comp)
3. Expander / Gate (C1 Gate)
4. Compressor + Expander / Gate w/ sidechain (C1)
5. Compressor + Expander / Gate w/ sidechain and IDR dithering (C1+)
 Waves C1+
The full-blown C1+ is the Swiss army knife of compressors, offering more flexibility than any other DirectX compressor plugin. It features a fully configurable compressor, gate, and sidechain with built-in EQ for stereo multiband compression. The compressor offers a lookahead mode for true zero-attack limiting. The sidechain can function as a conventional sidechain (where the frequencies that pass through the built-in EQ are used to control the dynamics which are applied across the whole track) or it can be used in "split" mode (which offers band-specific compression by applying the dynamics ONLY to those frequencies that pass through the EQ). A graph shows the transfer function being applied to the audio. A full complement of metering is provided, including input and gain reduction for BOTH the compressor and the gate, as well as stereo output meters with clipping indicators.
With flexibility comes complexity, and the full C1+ can be daunting if you've never used a mastering compressor before. I almost never use the full C1+ because I don't do a lot of mastering and when mixing, I usually want just a compressor on the insert. Fortunately, the basic C1 Compressor is as easy to use as any other compressor featured in this review. The C1 Compressor (or Gate) offers the usual controls: Ratio, Threshold, Attack, Release, and Makeup gain.
All the tools in the C1 family include a feature called "PDR" for Program Dependent Release. This feature shortens the release time for transients. When a transient is shorter than the time (in ms) shown on the PDR, then the release time is shortened. This feature is very useful when doing volume leveling on an instrument, or peak control in a final mix. It allows you to get more compression with less pumping and breathing.
The L1+ Ultramaximizer is Waves' premiere limiter. This tool has become so popular for mastering applications that Waves has released the L2 Ultramaximizer, which is a rack-mount version of the L1 software (as if people still buy rack effects).
You may have heard that the L1 is a "mastering limiter." Well, while the L1 was designed to be used as a mastering tool, it is also ideal for use on individual tracks in a mix. Be aware when using it as a track insert that you should disengage the noise shaping and dithering options, which should only be used as the last process performed on a final mix. The L1 uses only a couple of controls: threshold, target volume, and release. It is just a no-brainer to use this limiter to get your sounds as hot as they can get.
Pros
Where to begin?
Let's start with the user interface. Waves has opted for purely numeric controls with a transfer function graph to visually indicate the processor setting. To change the controls you can type in a value, or click and drag with the mouse to increase or decrease. At first the numeric controls were challenging. I was not used to using a compressor with numbers. I would just turn the knobs until I heard what I wanted, and everything was relative - "high ratio, low threshold, fast attack and release" means a limiter. I can say, however, that in little time I could use the numbers as effectively as a dial indicator, and of course the transfer function offers a quick display of the processor's effect.
 Waves C1 CompressorNote the very faint vertical line near the knee.That's a meter (it's brighter in real life).
And speaking of the transfer function, there is one feature that I love about the C1. Waves has superimposed the input level across the transfer function (above, it's the short vertical bar on the transfer function graph). This means that you can see the input level rising, crossing the threshold, and being transformed. What a great visual indicator of the effect! And you can drag the little arrow on the bottom of the graph to lower the threshold.
Waves has done a good job with efficiency. The standalone gate operates at only 3% CPU load, and the standalone compressor operates at only 7% load, as measured in Sound Forge 4.0. The full C1+ compressor / gate / dithering tool is a resource pig, gobbling up 19% of my available CPU resources. When the C1+ is compared against other similar plugins, the Waves plugins are not as efficient. However, if all you want is just a compressor or a gate and don't need the sidechain, then the Waves C1 Compressor or Gate tool will do the job more efficiently.
The sound is very good. In particular I really like the detection algorithm used in this plugin. Waves does not specify the algorithm, but apparently there is some intelligence under the hood. The result is a more controlled sound at high levels of compression than was available with the Cakewalk or Hyperprism plugins. This processor |
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