Saturation Plug-Ins | Warm It Up

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Whatever they call it—warmth, dirt, grit—what people long to hear in digital recordings is nonlinear harmonic distortion, also called saturation. In the analog world, the main sources of saturation are the three “T”s—tape, tubes, and transformers—and there are a growing number of DAW plug-ins that offer quite convincing simulations of these. I extensively tested eight such plug-ins for this story. Space and logistics limited my full attention to those, but I''ve included capsule descriptions of seven others in the sidebar, “More Saturation Choices.”

Three-T simulations fall into two categories: those that subtly alter the sonic character of your mixing environment and those that cross the line and deliver actual distortion. Although there is certainly some overlap, of the eight plug-ins covered here, HEAT, Phoenix, and the Studer A800 fall into the former category, and the rest alter your sounds more heavily.

Avid HEAT ($495) is available only for Pro Tools HD and comes bundled with all-new HD systems. It is more of an add-on than a plug-in, and works quite differently from all the other processing tools in this article. For one thing, you don''t add it as a track insert. When you activate HEAT for a given session, it becomes immediately active on all audio tracks. To view and alter HEAT''s bypass status for a given track, the HEAT controls must be visible in the Mix window. You can bypass HEAT for each track individually, or you can activate Pre to place the HEAT effect before other plug-in processing on a track.

A meter for each track glows orange, becoming brighter (based on the signal''s intensity) as more HEAT processing is being applied. You''ll find a master meter, global Drive and Tone controls, and a master bypass button in the master HEAT pane. Drive determines the amount of HEAT processing applied to all non-bypassed audio tracks; turning it clockwise adds more tube-like even harmonics, whereas turning it counterclockwise adds those along with more tape-like odd harmonics. The Tone knob is different from a normal EQ control because it interacts dynamically with the Drive setting and with signal energy. In general, counterclockwise is brighter and clockwise is darker.

If you create a new stereo audio track to print your final mix (as opposed to using the Bounce to Disk option), remember to bypass HEAT on this track. Otherwise, you will be adding HEAT to your mixdown and to each of your individual tracks—in effect, doubling the HEAT! The extra effect won''t be printed to your actual mix, so when you export the mix to a new stereo file, it will sound different from the one in your session. This is the only pitfall I''ve found; overall, HEAT is an extraordinarily user-friendly way to dial in effective, subtle yet powerful shifts in a mix''s harmonic content (see < href="" target="_blank">Web Clip 1).

Reel Tape Saturation ($295) is also available only for Pro Tools, but it does come in TDM and RTAS/AudioSuite versions so non-HD Pro Tools users can take advantage of what it and the other two plug-ins, Delay and Flanger, in the Reel Tape Suite ($495) offer.

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FIG. 1: Avid Reel Tape Saturation offers most of the control you''d find on a real tape machine.

The controls of Reel Tape Saturation are labeled Drive, Tape Speed, Noise, Bias, Cal Adjust, and Output (see Fig. 1). There are also three machine types (U.S., Swiss, and Lo-Fi) and two formulas (Classic and Modern). Having all of these options gives you a wide palette of tape saturation, from subtle harmonic additions to downright distortion. This plug-in is adept at adding midrange grit to vocals and guitars, as well as giving a bass guitar a little extra sizzle to poke through the mix (see Web Clip 2). I found the noise control handy for adding a slight amount of hiss to a vocal track that had been recorded on tape. That let me edit out in-between noises without leaving a too-silent gap.

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FIG. 2: Crane Song Phoenix''s interface may need a facelift, but the plug-in sounds like gold.

The Phoenix plug-in ($450, TDM only) was developed by renowned gear designer and Crane Song founder Dave Hill, who has a strong background in analog electronics and tape-machine design and service. Phoenix is a suite of five plug-ins esoterically named Luminescent, Iridescent, Radiant, Luster, and Dark Essence (see Fig. 2). Each has the same simple set of controls: Input Trim and Process Level knobs, along with three color changes creatively titled Gold (neutral), Sapphire (brighter), and Opal (warmer).

It seems odd to provide five separate components rather than integrating them within one interface, but the good news is that your settings automatically carry over if you swap in a different component. Each has its own harmonic distortion profile. The profiles vary from transparent to somewhat aggressive, although none of them deliver heavy distortion unless your signal is really loud to begin with or you put an additional gain stage before Phoenix. Phoenix does a great job of giving your entire mix a lift, especially if you put an instance on every channel. It''s like removing a thin sheet of gauze from your audio (see Web Clip 3).

Version 5 of McDSP''s Analog Channel ($449, TDM; $249, AU/RTAS) has two variations: AC101 and AC202. The AC101 was designed to emulate the saturation effect of analog consoles'' electronics. Although it is functionally reminiscent of a standard compressor—having attack, release, and curve controls, as well as a gain-reduction meter—it differs from a standard compressor in that it is not threshold-based; it is always affecting the audio.

The AC202 is a tape machine emulator. It has controls for changing the frequency of the LF roll-off, the amount of head bump, the head type, bias, playback speed, IEC EQ setting, and tape formulation. I found many useful settings on the AC101 and AC202, often landing on that magic mojo that analog electronics and tape provide (see Web Clip 4).

Using Analog Channel on spiky instruments—such as a somewhat unruly Wurlitzer electric piano—could give me a distortion I didn''t like. But when set right, it delivers a creamy overdrive that tames peaks while still allowing dynamic performance. The Analog Channel''s two variations were the only plug-ins on which I had to carefully watch my output level. There is an Auto function for the output level, but I generally prefer manual control. In short, Analog Channel allows much versatility so extra care must be taken to achieve proper gain-staging when setting your parameters.

PSP Audioware is a Polish company that is best known for its excellent VintageWarmer2 compression/saturation plug-in (see sidebar). PSP MixSaturator2 takes harmonic manipulation to a different level. It is available only as part of the shockingly affordable PSP MixPack2 bundle ($199, AU/RTAS/VST), which includes other handy mixing tools.

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FIG. 3: PSP MixSaturator2 is user-friendly and euphonically rewarding.

PSP MixSaturator2 has three sections: one for altering LF harmonic content (similar to a tape machine''s head bump in the low end), one for emulating the high-end compression that occurs at high levels on analog tape, and one for setting the amount and characteristics of nonlinear saturation (see Fig. 3). You get three tube (or Valve) shapes, three tape shapes, and one digital shape, which simulates hard clipping. Changing the shape significantly alters the signal level, which can make comparing settings a bit difficult but each shape has a distinctive sound, especially at higher saturation levels.

If you''re driving PSP MixSaturator2 hard, you can engage the OutSat button, which puts a brickwall limiter at the end of the signal path to prevent digital overs. You''ll find a Mix knob to dial in as much of the effect as you want in a phase-coherent parallel fashion. I have to say that each of the plug-ins in MixPack2 sometimes acted a bit erratically in Pro Tools, but when it was functioning properly, the PSP MixSaturator2 sounded fantastic, especially considering the price (see Web Clip 5). PSP says it is aware of the issues and is working to resolve them in an update.

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FIG. 4: Sound Toys Decapitator captures the analog feel, even in its interface, making it as fun to operate as it is to listen to.

SoundToys has built analog-type saturation into the lion''s share of its effects, such as PhaseMistress and EchoBoy (see my review in the November 2007 issue of EM), but Decapitator ($349, TDM; $179, AU/RTAS/VST, see Fig. 4) is the company''s first plug-in with saturation as the star. The interface is straightforward and streamlined, with only six knobs: Drive, Low Cut, Tone, High Cut, Mix, and Output. Of its three switches, Thump adds a boost right at the corner frequency of the low-cut filter; Steep alters the shape of the high-cut filter; and Auto automatically adjusts the output control when you set the drive level.

You get five choices of saturation style, modeled on hardware by Ampex, Chandler Limited/EMI, Neve, and Thermionic Culture. The Punish button adds a whopping 20dB of gain to the plug-in''s input stage. It goes without saying that you can produce sounds with this effect that will give you a buzz cut—if you duck in time. Decapitator excels at producing extreme (but also extremely pleasant) distortion. It''s also useful at lower drive levels to add a touch of edge to the midrange. That brings out elements that need to assert themselves more in the mix, such as electric guitar, snare drum, vocals, and piano (see Web Clip 6).

Emprical Labs EL7 Fatso Jr. was one of the first hardware boxes devoted to emulating the effects of analog tape. Universal Audio offers two variations on the EL7: Fatso Jr. and Fatso Sr. ($299, AU/RTAS/VST; requires UAD-2 hardware). The Jr. and Sr. variations share the same basic controls: input, Compression Mode selector, warmth amount, Transformer (Tranny) enable, and output. Fatso Sr. adds four controls for the compression circuit (threshold, attack, release, and a sidechain highpass filter) and a level control for the Tranny.

Whether or not the compressor is engaged, Fatso adds second- and third-order harmonics that increase as your input level goes up. This emulates how tape and tubes react to dynamics. The Warmth circuit simulates the softening effect that tape has on high frequencies, and the Tranny control adds extra harmonics to low frequencies to make them apparently louder without boosting the headroom-hungry fundamentals. The four Fatso components are interrelated, so a change to the compressor settings affects the sound of the transformer, and so on. The Fatso is highly effective at sculpting the harmonic content of just about anything you throw at it (see Web Clip 7).

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FIG. 5: The tape reels of Universal Audio Studer A800 actually spin. Although it''s a real client-pleaser, you can click the IPS knob to turn it off to keep from getting dizzy.

The newest addition to the UAD-2 DSP card family, the Studer A800 ($349, AU/RTAS/VST; requires UAD-2 hardware) painstakingly re-creates the sound and workings of a single tape machine: the Studer A800 (see Fig. 5). You get a selection of four tape types and have control over many other virtual tape-deck functions, including inches-per-second, reference level, hum/hiss amount, emphasis EQ curve, and input and output levels. Notably, you can monitor either directly through the virtual tape machine''s electronics or from either of the heads (Sync or Repro), each of which has its own bias and EQ settings.

Perhaps the most unusual feature of the A800 is its ability to gang the controls. The Gang button, when enabled on any instance of the A800 in a given session, completely links the controls for all instances of the plug-in in that session. (Regrettably, the parameters become unlinked when you scroll through presets, but this will be addressed in a future release.) This can be extremely handy for setting up the A800 to work the same way as HEAT, where global changes affect all of your tracks. With the A800, once your global settings are made, you can switch Gang off to fine-tune the saturation type and amount for each channel (see Web Clip 8). Keep in mind that using an A800 on each channel comes at a processing cost. For example, 18 tracks of A800 processing used 60 percent of my UAD Quad card running at 96kHz.

I enjoyed using each of these plug-ins. My mixes during the past few months have benefited from the selective use of each, even though a lot of the material was tracked to tape in the first place. In terms of ease of use for the mix''s overall sound, HEAT is clearly the standout. The A800, with its ability to gang controls, comes in a close second and is more flexible. Phoenix has the most stripped-down controls, but with five variations and three tone settings, you actually get 15 ways to liven your sounds.

Analog Channel and Fatso add some standard compressor functions, giving you more ways to tame the dynamics while adding oodles of analog character. Reel Tape Saturation excels when driven hard and is straightforward for anyone familiar with tape machines. Priced at less than $200, Decapitator and PSP MixSaturator2 share honors for the most bang for your buck. They are the only two available in all three major formats and don''t require special hardware.

Owing to their diversity, a simple comparison of these plug-ins is not easy. However, I did run a section of a song through a few presets on each of the eight plug-ins and you can listen to the results online (see Web Clips 9, 10, 11, 12, 13, 14, 15, and 16.

Here are short descriptions of seven saturation plug-ins not covered in the main article but worthy of your consideration.

Antares retooled its popular Tube plug-in for its Evo suite, which is designed for vocal processing. Warm (part of AVOX Evo bundle; $399, AU/RTAS/VST) has a very simple control set, emulates two different tubes, and has a handy mode that isn''t transient-dependent.

Straightforward controls and an extremely low price set TapeHead ($69, TDM/RTAS)—and Massey''s other stellar plug-ins—apart. With only a Drive knob, a 3-position Tone switch, and an Output control, it''s extremely easy to dial in thick, rich tones.

Because the effect runs on the DSP of the interface itself, Metric Halo''s Character (included with all current company interfaces) can be applied during either tracking or mixing, and it places zero strain on your host CPU. There are nearly 20 different effects, including various tubes, transformers, and mic preamps, giving a tremendously wide variety of color.

This plug-in appeared during the writing of this article, and it is an affordable way to get into the tape-machine-emulation game. Magnetic ($129, AU/RTAS/VST) from Nomad Factory has many features and provides great versatility. I found that it delivered some of the most convincingly vintage sounds of the entire lot.

The PSP VintageWarmer 2 ($149, AU/RTAS/VST) compression-saturation plug-in has been around for almost a decade. VintageWarmer was the first plug-in I ever heard that made me think computers could be good tools for mixing records, and it still gets daily use in my studio.

This is a simple but extremely effective duo of plug-ins. Slate Digital''s Virtual Console Collection ($250, AU/RTAS/VST; iLok2 required) is in beta-testing as of this writing, but should be available by the time you read this. One plug-in models a channel strip and the other models the master bus section of four different legendary consoles. These emulations sound extremely good and can be grouped across multiple channels.

I found the sound of the VirsynVTAPE Suite ($219, AU/RTAS/VST; Syncrosoft dongle required) plug-ins—Saturator, Delay, and Flanger—very convincing. Although they gave me a number of problems on my Pro Tools system, they worked well in Apple Logic and BIAS Peak. The interface leaves something to be desired, but their excellent sound is more important. When you push Saturator hard, the distortion remains truly analog-sounding.

Eli Crews operates New, Improved Recording, a studio in Oakland, Calif.