Resonance laboratory · Velstraven

A small room of chapter 3. When you walk in, the room card reads: The goblets ring out of tune with the reference reeds.

Narrated walkthrough

Resonance laboratory from its entrance — Resonance laboratory: how to solve it

Getting there

Chapter 3, second upper floor. The west doorway of the Workshop and observatory hub, which you reach from the warmth-seeking vine once chapter 2 is done.

What is wrong

"The goblets ring out of tune with the reference reeds." Each goblet has a gauge beside it: a dark reed that moves with the water level, and a fixed reference reed with an open loop at its tip.

What you can work

Left goblet: Holds 0.5 L; its note needs 1.5 L. Too little water, so its dark reed rides above the reference.
Middle goblet: Holds 1.5 L; its note needs 0.5 L. Too much water.
Right goblet: Empty; its note needs 1.0 L.
Pitcher: Holds 2 L. Handle it to pick it up; while you hold it, Handle on a goblet pours 0.25 L in.
Basin: Catches what the goblets spill or drain. Handle refills the pitcher from it; Turn (X) empties it through its outlet.
Compare: The comparison lever. It checks all three goblets, and each must have been rung since its water last changed.
Reading lamp: Optional light to read the room by: Handle toggles it, Heat lights it, Supply liquid douses it, Place light roots a lasting flame blossom in its cup. It works none of the room's fittings.
Reading shutter: Optional: Handle or Orient opens a high window for daylight from a second angle. It works none of the room's fittings.

Solution

A nudge

Every pour or draw in this room moves exactly 0.25 L, so the job is counting: +1.0 L left, -1.0 L middle, +1.0 L right.

The full solution

Bind Supply liquid (Water, Water, Water) and Draw off liquid (Wind, Water, Water) to two slots.
Every pour or draw in this room moves exactly 0.25 L, so the job is counting: +1.0 L left, -1.0 L middle, +1.0 L right.
What you see: The slot cards show both spells.
Aim at the Left goblet and cast Supply liquid four times.
Four doses of 0.25 L take it from 0.5 L to its 1.5 L mark.
What you see: "The stream raises the goblet's water level; its dark reed moves." The dark reed settles over the reference reed.
Aim at the Middle goblet and cast Draw off liquid four times.
Each cast lifts 0.25 L out into the basin, taking it from 1.5 L down to 0.5 L.
What you see: "Lifted water leaves the goblet for the basin; its dark reed moves."
Aim at the Right goblet and cast Supply liquid four times.
The empty goblet needs 1.0 L for its note.
What you see: Its dark reed comes down onto the reference reed.
With empty hands, Handle (E) each goblet once: left, middle, right.
A tap rings the goblet. The lever only trusts a goblet that has rung since its water last changed, so ring them after the last pour, not before.
What you see: "The tapped goblet rings." The pitch drops as the water rises.
Handle the Compare lever.
All three water levels are within 0.1 L of their marks and all three have rung.
What you see: "The comparison matches the reference reeds." and "Resonance laboratory settled."

Other ways that work

No spells at all: Handle the Pitcher to pick it up, then Handle the Left goblet four times and the Right goblet four times (the pitcher's 2 L is exactly enough). Handle the Pitcher again to put it down. Use Turn a fitting (X) on the Middle goblet four times to drain 1.0 L into the basin. Ring all three and pull the lever.
Mix and match: any pour, spell dose or drain moves the same 0.25 L, so you can, for example, fill with the pitcher and drain with Draw off liquid.
If the pitcher runs dry, Handle the Basin to refill it from what has drained there (0.5 L per press).

Watch for

While you hold the pitcher, Handle on a goblet pours instead of ringing it. Put the pitcher down before you ring the goblets.
Ringing must come after the last change. Any pour, drain or spell dose on a goblet clears its ring.
The lever names the first goblet that is wrong, for example "…the left goblet's reed is off its reference." or "…the middle goblet has not been rung since its water last changed."
Looking at a goblet tells you which way it is off: "Its dark reed rides above the matching reference reed; the goblet holds too little water for that note."
A goblet holds at most 2 L. Overfilling spills into the basin, and the basin's overflow leaves through its outlet.

If it goes wrong

Nothing breaks here. Correct a level with another pour or drain, ring again and pull the lever again.
Hold R for one second ("Keep holding to restart from the room's autosave"), or use the pause door "Restart from autosave", to put the room back as it was when you walked in: "Automatic room-entry save restored." Rooms you settled earlier stay settled.

Achievements here

In Resonance: Solve the Resonance laboratory.
Perfect Pitch, Quickly: Solve within 90 seconds of entering. Bind Supply liquid and Draw off liquid before you walk in; the clock starts the moment you step into the room. Twelve casts (4 left, 4 middle, 4 right), three taps and the lever take well under a minute. The no-spell pitcher route is about as quick. The 90-second limit is provisional and may change.
Fill and Drain: Fill and Drain: on the Middle goblet, cast Supply liquid once and then Draw off liquid within 20 seconds. Then draw off four more times so it still ends at 0.5 L.

Spells used

Supply liquid, Draw off liquid.