Triodia's plate reverb: how it works and how to use every knob

Why a plate, for vocals?

A plate reverb was originally a real object: a large, thin sheet of steel hung in a frame, with a driver that shook it like a speaker and pickups that listened to the vibrations. The most famous of them, the EMT 140, appeared in 1957 and ended up on countless vocal records.

Plates became the classic vocal reverb because they sound dense and smooth from the very first moment. A room or hall has distinct early reflections, which you hear as "the vocalist is standing over there". A plate has none of that: it adds a bright, even shimmer that makes the voice bigger without pushing it to the back of the mix.

The algorithm: Dattorro's plate

Triodia's Plate follows the design Jon Dattorro published in 1997 in the Journal of the Audio Engineering Society ("Effect Design, Part 1: Reverberator and Other Filters"), itself modeled on the EMT 140. It's a reference design in digital reverb, known for a lush, natural tail with very few metallic artifacts. In plain terms, the sound goes through four steps:

• Input
• →
• Diffusers
• →
• Tank (loop)
• →
• Stereo taps

1. Input. The signal is summed to mono before entering the plate, just like the single driver bolted to a real EMT 140.
2. Diffusers. Four all-pass filters smear each sound into a dense cloud of tiny echoes. This is what makes the reverb smooth from the start instead of "slappy".
3. The tank. Two cross-connected halves pass the sound back and forth in a loop, like vibrations travelling across the steel sheet. Each pass loses a little energy (that's the decay) and a little high end (that's the damping). A very slow modulation, under 1 Hz, keeps the tail from ringing on one pitch.
4. Stereo taps. The left and right outputs are read from different points around the tank, like the two pickups on a real plate. Because they hear different reflections, the result is wide and natural.

All delay times come from Dattorro's paper and are rescaled to your project's sample rate, so the plate sounds the same at 44.1, 48 or 96 kHz.

Where the Plate sits in the chain

The Plate comes after the de-esser, the tube compressor and the echo. Two things follow from that:

• The reverb receives an already controlled, de-essed vocal, so it doesn't splash on loud notes or hiss on the S's.
• If the echo is on, its repeats also go into the plate. That's the classic "echo into reverb" sound: the repeats melt into the tail instead of sounding like separate copies.

The LED next to the PLATE label switches the whole section on and off, with a short fade so there's no click.

Every knob, explained

SIZE: how long the tail lasts

SIZE sets how much energy the sound keeps on each trip around the tank. Low values give a short, tight plate that thickens the voice without an obvious tail; high values give a long, lush wash. The default is 50%.

• 15–30%: short and subtle, for rap, rock and busy arrangements.
• 40–55%: the all-round vocal plate.
• 70–90%: long and dramatic, for ballads, ambient and effect throws.

Rule of thumb: the faster the song, the shorter the plate. A tail that is still ringing when the next phrase starts blurs the words.

DAMP: how dark the tail gets

DAMP is a gentle low-pass filter inside the tank loop. Because the sound passes through it on every trip, its effect grows over time: the start of the reverb stays bright and the tail gets progressively darker, just as high frequencies die out first in a real plate. The default is 50%.

• Low DAMP (30–40%): a bright, shimmering tail, the classic airy pop plate.
• High DAMP (60–70%): a warmer, darker tail that stays behind the voice. Good with bright singers or harsh recordings.

If the reverb sounds "fizzy" or makes the S's linger, raise DAMP before you lower the MIX.

WIDTH: how wide the reverb is

WIDTH controls the stereo spread of the reverb only, using mid/side processing on the wet signal. Your dry vocal stays exactly where it is. The default is 100%.

• 100%: the full, natural width of the two pickups.
• 70–90%: a bit more focused, useful in dense mixes where the sides are already crowded.
• Around 30%: a narrow, almost mono reverb that sits right behind the voice. Great for vintage sounds; the Vintage Radio preset uses it.

PRE-DLY: space before the reverb starts

PRE-DLY (pre-delay) holds the signal back from 0 to 200 ms before it reaches the plate. That gap lets the dry consonants be heard clearly before the reverb blooms, which keeps the words intelligible even with a generous reverb. The default is 20 ms.

• 0–15 ms: the reverb hugs the voice, for an intimate, close sound.
• 20–40 ms: the sweet spot for most lead vocals.
• 60 ms and up: a clear separation between voice and reverb, for big, dramatic plates.

Tip: a pre-delay that matches the song's subdivision (for example 1/64 or 1/32 of a note) makes the reverb feel locked to the groove.

LOW CUT: keep the low end clean

LOW CUT is a high-pass filter on the signal going into the reverb, from 20 Hz to 1 kHz. Low frequencies in a reverb tail rarely add anything useful to a vocal; they build up as mud and fight with the bass and kick. The default is 200 Hz. Because the filter is only on the reverb's input, your dry vocal keeps all of its body.

• 200–300 Hz: a clean tail that still feels full.
• 350–500 Hz: a thinner, lighter reverb for dense mixes or vintage effects.

MIX: how much reverb you hear

MIX balances the dry vocal against the reverb. It isn't a simple crossfade: up to 50%, the dry vocal stays at full level and only the reverb rises. At 50% both are at full level, and only above 50% does the dry signal start to drop. In practice, anywhere below 50% the knob works like a reverb send, so adding reverb never makes the voice quieter or weaker. The default is 20%.

• 5–10%: felt more than heard. The vocal sounds polished but "dry".
• 15–20%: an audible, classic vocal plate.
• 25–35%: a big, obvious reverb for ballads and effects.

Set MIX last, after SIZE, DAMP and the filters. Raise it until you clearly hear the reverb, then back it off slightly. You should miss it when you switch it off, not notice it when it's on.

Starting points from the factory presets

Triodia's presets are a good map of how these knobs work together. These are their Plate settings:

The Podcast and Voice-Over presets turn the Plate off: spoken word usually sounds best dry and close.

Notice the patterns: the "bigger" the style, the higher the SIZE, PRE-DLY and MIX together, while faster, denser styles (rock, rap) pair a short plate with more damping and a higher low cut.

A quick recipe

1. Start from the preset closest to your song.
2. Set SIZE to the tempo: shorter for fast songs, longer for slow ones.
3. Adjust DAMP until the tail sits behind the voice without sounding dull.
4. Raise PRE-DLY if the words lose clarity.
5. Raise LOW CUT if the mix gets muddy when the reverb is on.
6. Finish with MIX, and compare with the Plate switched off.

For the rest of the chain, see how to get warm tube vocals for free.