500 Series Vocal Chain: Order, Settings, Modules

500 Series Vocal Chain: Order, Settings, Modules

  • 06.09.2026
  • Michael Krusch
  • Story
  • Basics
  • Vocal Chain

A vocal chain in the 500 series looks simple from the outside: three or four modules in a rack the size of a lunchbox, a microphone on one side, your interface on the other. Then the questions start. Which module comes first? Does the EQ go before or after the compressor? Opto or VCA? How much gain reduction? And is a rack full of hardware even the right answer, or would a channel strip or a plug-in do the same job?

We build three modules for that rack in Berlin: the Vocal Leveler 500, an opto compressor, the MythEQ 500, a four-band equalizer, and the MythVCA 500, a VCA compressor. So this is the explanation from the workbench: what a vocal chain is, why the order is what it is and when you should break it, what each stage does, which compressor type belongs where, starting settings you can dial in tonight, and the honest part at the end about when a 500 series rack is not the right tool.

In this article:

What a vocal chain is, and why the 500 series was built for it

A vocal chain is the series of processors a voice passes through between the microphone and the recorder or the mix bus. In a DAW that means a row of plug-ins. In hardware it means a row of boxes, and every box is a decision: what it does, where it sits, how hard it works. The classic chain has three stages. A preamp brings the microphone signal up to line level. A compressor evens out the level. An equalizer shapes the tone. Everything else, de-essers, saturation, a second compressor, reverb, is optional and comes later.

The 500 series is used this way because engineers wanted to build exactly that kind of chain from parts. The format itself was not invented for it: it goes back to API founder Saul Walker and the modules of API consoles in the late 1960s, and only later did the modules move into racks of their own. Since 2006 the VPR Alliance, set up by API, defines the mechanical and electrical standard so that modules from different manufacturers fit the same racks. A rack, often called a lunchbox, supplies every slot with ±16 V and, in the standard, up to 130 mA on each of the two rails, plus 48 V for phantom power with a budget of 5 mA. The modules plug into a 15-pin edge connector and the rack takes care of power and connections. You choose the modules, you choose the order, and if you change your mind, you pull one out and slide another one in.

For vocals this is the interesting middle ground. A full console is more than one voice needs. A single channel strip locks you into one designer's idea of a chain. A 500 series rack lets you combine a preamp you love with the compressor and EQ you want behind it, from anyone who builds in the format. That is why Tegeler builds compressors and an equalizer for it: they are the two stages after the preamp where the character of a vocal chain is decided.

The order: preamp, compressor, EQ. And why it is not a law

The default order for a recording chain is preamp, then compressor, then EQ. The preamp has to come first, because everything after it needs line level. The compressor comes second because its job is to hand a steady signal to whatever follows. The EQ comes last because you want to shape the tone of the finished, leveled voice, not of a voice that is still jumping around.

The reason this order is a default and not a rule has to do with how a compressor listens. A compressor reacts to level. Anything that changes the level before it changes what it does. Sound On Sound's Mike Senior put it in one sentence: "Equalisation is primarily about changing signal levels, albeit in carefully specified frequency regions, so pre‑compression EQ can alter the gain‑reduction action of the compressor, but post‑compression EQ won't." Audrey Martinovich at iZotope describes the two directions: "Dramatic boosts in EQ mean the threshold is met at a different level than it otherwise would have been without the EQ, causing the compressor to lower the level in response." And the other way around: "When compression is used before EQ, some of the compression is undone when we boost frequencies with the EQ."

From that follow the two cases where you break the default. If the recording has a problem the compressor should not hear, a rumble below the voice, a boomy room resonance, a proximity effect that makes every plosive a bass drum, you cut that before the compressor. Otherwise the compressor clamps down on the rumble and lets the words through unevenly. If you want to boost, you boost after the compressor, so the compressor does not immediately take the boost away again. Engineers call the combination a sandwich: narrow, corrective cuts before compression, broad, musical boosts after it. In a 500 series rack that means an EQ in front of the compressor and one behind it, or, more often, one EQ behind the compressor and a high-pass filter somewhere in front, on the preamp or on the microphone itself.

One more thing about the order, because it decides how hard you work each stage. A chain used while recording is a commitment; what the compressor does on the way in is on the take forever. A chain used while mixing, with the recorded vocal sent out through the converters and back, is reversible. Both are legitimate. Recording through the chain gives you a more finished sound to build the mix around and a singer who hears a record-ready voice in the headphones. Mixing through the chain lets you push harder, because you can always start again. Whichever you choose, keep the gain reduction while recording on the conservative side. You can always add more later. You cannot take it off.

Stage 1: the preamp and the level

The preamp is the one stage of a vocal chain Tegeler does not build in the 500 series format, and we would rather say that plainly than write around it. Your chain needs one. It can be a 500 series preamp from another manufacturer in the first slot of the same rack, or the preamp in your audio interface. For a first chain the interface preamp is a perfectly reasonable start. Its job is to bring the microphone signal up to line level as cleanly as your budget allows and to set the level that everything behind it will see.

That level matters more in hardware than in a DAW. The operating level in a studio, and of these modules, is +4 dBu; the Vocal Leveler 500 accepts up to +20 dBu at its input, the MythVCA 500 up to +22 dBu. Those are ceilings, not targets. Set the preamp so that the singer's loud passages sit comfortably below the point where the preamp itself starts to distort, and then leave it alone. Every knob after the preamp assumes the level coming in is stable from take to take. If you change the preamp gain between takes, the compressor behind it is suddenly working differently and your carefully found setting is gone.

If your preamp has a high-pass filter, this is the place to use it: 80 Hz or so for most voices, less for a deep male voice with real low end you want to keep. That is the corrective cut from the sandwich above, and it means the compressor never has to react to a stand bump or a room rumble.

Stage 2: opto for leveling, VCA for punch

A compressor turns the level down when the signal gets loud, and how it does that depends on the component that does the turning. Two families matter for vocals, and Tegeler builds one module of each.

Opto. In an optical compressor the audio signal drives a light source, and the light falls on a light-dependent resistor that sets the gain. The physics of that resistor gives the opto compressor its character: it does not react instantly, and the classic T4 cells let go in two stages, quickly at first and then slowly over seconds. The classic example is the Teletronix LA-2A, whose average attack is around 10 ms and whose release, according to Universal Audio, is "about 60 milliseconds for 50% of the release, and anywhere from 1 to 15 seconds for the rest." Attack Magazine's Adam Douglas sums up the family: optical compressors "are not what you'd call fast." That is exactly why they suit a voice. A singer does not change level in microseconds; a phrase swells and falls over a second or two, and an opto compressor follows that shape like a hand on a fader.

The Vocal Leveler 500 is that idea in a single slot. Its compressor circuit comes from our Vari Tube Recording Channel: an input transformer from our own production, the opto stage, and behind it a FET stage wired so that it produces the same harmonics a tube would. There is no tube in the module; the FET stage produces the same harmonics, without the heat and the current draw. The controls are deliberately few. Two stepped knobs, Gain Reduction and Output, and two toggle switches: In/Bypass/Link, where Link couples two modules for stereo, and a timing switch with fast, auto and slow. There is no meter on the front; you set it by ear, and that is intentional. The maximum gain reduction is 12 dB, and that number tells you what the module is for. It is a leveler, not a limiter. Its designer describes the goal as audibility without loudness: the voice becomes more assertive and its level stays even, so it sits in the same place in the mix from the first line to the last, and in the end it does not sound compressed. It sounds like a singer with very good control.

VCA. In a VCA compressor the gain is set by a voltage-controlled amplifier that follows a control signal derived from the audio. It has no light and no photoresistor physics to slow it down, so it can be as fast as you tell it to be, and it gives you the full set of controls: ratio, attack, release. Douglas describes the family as "fast and punchy on rhythmic material," which is why VCA compressors run on drum buses and mix buses. On a voice a VCA compressor is what you reach for when the vocal needs to hit, not just to sit: a rap verse, a shouted chorus, a stacked hook that has to cut through a wall of guitars.

The MythVCA 500 gives you that set in a slot: a Threshold knob, ratios of 2:1, 4:1 and 10:1, attack from 0.1 to 30 ms, release from 100 ms to 1.4 s or automatic, an Output knob, and a low-cut in the sidechain, switchable to 60 or 120 Hz, so that the low end of a voice or an instrument does not trigger the compressor. A row of LEDs shows the gain reduction from 2 to 18 dB. All knobs are stepped. A bridge for linking two modules to stereo comes in the box. The design brief was a VCA compressor that leaves nothing out, and Markus Galla at Amazona.de came to the conclusion that it "handles the usual repertoire of a VCA compressor, but does so excellently and with the best quality" (translated). You can read that review in Amazona.de reviews the MythVCA 500.

Which one, or both? If you have one compressor slot and you record singers, take the opto. Leveling is the job that comes up on every vocal, punch is the job that comes up on some. If you have two slots, put them in series, opto first: the Vocal Leveler evens the performance out with a few decibels of gain reduction, and the MythVCA behind it catches the peaks that are left and adds the attack. Two compressors each working a little sound more natural than one compressor working hard; that is an old trick in vocal production and the 500 series makes it a matter of two slots. And if you want the wider picture of how the compressor families differ, including the tube-based vari-mu type in our 19-inch units, it is in Vari-Mu compression explained.

Stage 3: the EQ after the compressor

Behind the compressor the voice has a steady level, and now the EQ can do what it is for: decide how the voice sounds, not how loud it is. On a vocal the usual moves are few and they are the same in every genre, only the amounts change. Take away what does not belong to the voice at the bottom. Reduce the mud where the room and the chest resonate, roughly between 200 and 400 Hz. Find the presence that makes words intelligible, somewhere between 2 and 5 kHz, and give it a little. Open the top, above 10 kHz, for air. Those ranges are rules of thumb, not measurements; where exactly a given voice needs the cut or the boost is what your ears are for.

The MythEQ 500 is our equalizer for that job. It is an active four-band design without tubes, built with film capacitors and with output transformers from our own production. The four bands cover a voice from bottom to top: a low shelf switchable to 50, 55, 65, 100, 300 or 450 Hz, a low-mid bell at 80, 120, 190, 330, 900 Hz or 1.3 kHz, a high-mid bell at 1, 1.5, 2.5, 4.5, 12 or 16 kHz, and a high shelf at 3, 3.3, 3.7, 5.5, 8.5 or 10 kHz. Every band offers up to 15 dB of boost or cut. The frequencies are stepped, and so are the gain knobs, which is the point in a rack: you can write a setting down in four lines and recall it in ten seconds next month. For a stereo source, matched pairs are available.

Its character is the opposite of our passive tube equalizer, the Classic Equalizer EQP-1: where the EQP-1 colors a whole track softly and broadly, the MythEQ is tight and gets hold of a single track. On a vocal that means presence you can point at. Amazona.de's Jörg Hoffmann heard a unit that "convinces with character, roughness and assertiveness, without losing sight of the classic values of an equalizer" (translated). A voice that has been leveled by an opto compressor and then given a few decibels of presence and air by an EQ with its own output transformers is, in one sentence, what most people mean when they say a vocal sounds finished.

Starting settings you can try tonight

These are starting points for a lead vocal, derived from the modules' controls and from common practice, not from a measurement of your voice in your room. Set them, listen, then move one knob at a time.

Preamp. Gain so that the loudest phrase stays well clear of the preamp's own distortion. High-pass filter on, around 80 Hz, if the preamp has one.

Vocal Leveler 500. Timing switch on auto. The module has no meter, so watch the input meter in your DAW and listen: turn Gain Reduction up until the loud phrases come down by roughly 3 to 6 dB and the quiet ones are barely touched; if the voice starts to sound held back, go one step down. Output so that the level leaving the module matches the level going in, so you compare the effect and not the volume. Use slow for a ballad where the compressor should breathe with the phrase, fast for spoken or rapped material whose level changes from word to word.

MythVCA 500, if you use it as a second stage. Ratio 4:1. Attack in the range of a few milliseconds, slow enough to let the consonants through, fast enough to catch the peaks the opto stage left. Release on auto to start with. Sidechain low-cut at 120 Hz so the compressor reacts to the voice and not to the chest. Lower the Threshold until the LEDs show another 2 to 4 dB on the peaks only. If you use the MythVCA as the only compressor, take the 4:1 ratio, an attack around 10 ms and a release around 300 ms as the first setting, and lower the Threshold until the LEDs show 4 to 6 dB on the loud words.

MythEQ 500. Low shelf at 100 Hz, cut 3 to 6 dB, unless the preamp already filtered; the filter in front of the compressor is the better place, because here the compressor has already reacted to the low end. Low-mid bell at 330 Hz, cut 2 to 3 dB if the voice sounds boxy, otherwise leave it flat. High-mid bell at 2.5 or 4.5 kHz, boost 2 to 3 dB for presence; 2.5 kHz makes the words fuller and less sharp, 4.5 kHz makes them cut through. High shelf at 8.5 or 10 kHz, boost 2 to 4 dB for air. Then bypass the module and listen again. If the bypassed version sounds better, you have overdone it, and that is one of the most useful things an EQ tells you.

And a note on what no setting can do. Mike Senior wrote in Sound On Sound that compression "is simply not an intelligent enough tool to keep a lead vocal exactly where you want it throughout most mixes," and he is right. The chain gets you most of the way. The last few decibels of a vocal that sits perfectly are fader automation, in every studio, at every price.

Into the rack: slots, current, recall, and when not to

Slots and order. Left to right, in the order of the signal: preamp, Vocal Leveler, MythEQ, and the MythVCA if you use it, either directly behind the Vocal Leveler or behind the EQ for the pop-record variant where the last stage adds density; in that case the compressor works on your EQ boosts, which you accept on purpose and balance with less gain reduction. Many racks have no internal routing between slots, so you connect the modules with short cables on the back; some racks offer a cascade link between neighboring slots, and then the order in the rack is the order in the chain.

Current. The standard budgets 130 mA per rail and slot, and Sound On Sound's Matt Houghton warns that "plenty consume more, and some far more." The MythVCA 500 draws 100 mA on its ±16 V rails. Before you buy a rack, add up the current of every module you plan to put in it and check it against what the rack's power supply delivers, with a margin. A rack that is short on current does not warn you; the modules simply stop doing what they were designed to do.

Stereo. All three Tegeler modules are mono, which is what a lead vocal is. For a stereo source, two Vocal Levelers couple through the Link position, two MythVCAs through the supplied bridge, and the MythEQ is available in matched pairs.

Recall. Stepped knobs on all three modules mean the whole chain can be written down on a sticky note: switch positions and knob steps. That is the quiet advantage of a rack over a console channel with continuous pots, and it is the reason you can use the same chain for the whole album and know that song eight sounds like song one.

When not to. Three cases, honestly. If you record vocals a few times a year, a good plug-in chain does the job and the rack stands idle; hardware pays off when it is used. If you want preamp, compressor and EQ from one hand in one unit, with the EQ switchable in front of or behind the compressor and even into the compressor's sidechain for de-essing, that is what a channel strip is for, and it is exactly what our Vari Tube Recording Channel does in 19 inches; the Vocal Leveler's compressor was born there. And if the problem you are trying to solve is the whole mix, not the voice, the answer is a bus unit, not a vocal chain. The 500 series rack wins when you want to choose your own preamp, want to grow the chain slot by slot, and want the thing to fit in a bag. If that is you, the chain in this article is a good place to start, and if you would rather watch it being built than read about it, 2probeats does exactly that with the MythEQ and the Vocal Leveler in his 500 series vocal chain video.

Want to hear this vocal chain in your own rack for 14 days?
More about the Vocal Leveler 500

Test the Vocal Leveler 500 · Test the MythEQ 500 · Test the MythVCA 500

Tegeler Logo

End your inner battle between digital and analog.

© 2005-2026