Twice a year keeps a piano playable, four times a year keeps it recordable, and in the San Fernando Valley the schedule is set by humidity swings rather than by how much you play. A piano in a Burbank house lives through winter humidity in the fifties and Santa Ana conditions in the teens, sometimes in the same month, and the soundboard moves with it. That movement, not the hammers hitting strings, is what pulls a piano out of tune. When a session is booked, the timing depends on the instrument: one that holds a tuning is done two or three days ahead so it can settle in the room, and one that does not hold is done on the session morning, because a tuning it will not keep is worth nothing three days early. Which of those you have is in the physics below. ## Why does a piano go out of tune when nobody plays it?
Because the soundboard is wood under tension, and wood tracks the moisture in the air.
A piano holds roughly 18 to 20 tons of combined string tension across about 220 strings, and all of it presses down through the bridges onto a spruce soundboard that is deliberately built with a crown, a slight upward curve. When the air dries out, the board loses moisture, the crown flattens, tension drops, and the piano goes flat, most audibly in the middle two octaves where the bridge pressure is highest. When humidity climbs, the board swells, the crown rises, and those same notes go sharp. The treble and the bass, sitting on different bridges with different string lengths, move by different amounts, which is why a neglected piano sounds not just flat but internally out of proportion.
Manufacturers say this plainly rather than as a sales line. Steinway's own service guidance recommends tuning at least twice a year and notes that the piano changes with seasonal humidity, and the Piano Technicians Guild describes the same relationship in its owner material. The number itself is less important than the reason: you are tuning against the weather, not against your practice hours.
What does the Los Angeles climate specifically do?
It swings, and it swings fast. Coastal marine layer mornings put a Valley house at comfortable humidity, then a Santa Ana event drops outdoor relative humidity into the single digits or teens within a day, which the National Weather Service Los Angeles office tracks through the fall and winter. Add a heater or air conditioning and the indoor number goes lower still.
The target inside the room is 40 to 50 percent relative humidity, held steady. Steady matters more than exact. A piano at a constant 35 percent is in better shape than one that oscillates between 30 and 60 percent every few weeks, because it is the movement that loosens glue joints, opens soundboard cracks and unseats the bridge.
Three practical measures, in order of cost:
1. A hygrometer in the room, near the piano, not across the house. A cheap instrument tells you whether you have a problem at all. Most people guess wrong about their own room. 2. Placement. Off exterior walls, out of direct sun, away from a heating or AC vent and away from a fireplace. A piano under a west-facing window in Burbank takes a daily temperature ride nothing else in the house takes. 3. Room or piano humidity control. A room humidifier in dry months, or an under-piano climate system, if the instrument justifies it.
How do you know it needs tuning before a session?
Play an octave in the middle, then the same octave an octave up, and listen to the beating. Then play a single note and listen to the unisons: each note in the middle and treble is struck by two or three strings tuned to the same pitch, and when they drift apart you hear a shimmer or a wobble that decays unevenly. That wobble is the first thing a microphone exposes and the last thing a player consciously notices, because the ear adapts to a piano it hears every day.
Two other checks before booking a recording:
- Pitch level. If the instrument sits noticeably below A=440 Hz, a single tuning will not hold. Bringing an entire piano up in pitch changes total tension on the frame, and the tuning drifts as the structure equalizes, which is why a pitch raise is a rough pass followed by a proper tuning, sometimes on a second visit.
- Anything mechanical. A sticking key, a buzzing note or a pedal that engages late are regulation and repair issues, not tuning issues, and they will still be there after the tuning if nobody is told about them.
When should the tuning happen relative to a recording session?
It depends on the piano, and the question that decides it is whether this instrument holds a tuning.
If it does, meaning a stable piano in a room whose humidity does not swing, then two or three days before, in the room's normal condition, with the same door and window state you will have on the session day. That gives it time to settle where it will actually be working.
If it does not hold, which covers anything recently moved, recently restrung, left years between visits, or sitting well below pitch, then the session morning, first slot of the day. A tuning that will not survive three days is not worth doing three days early, and an instrument in that state usually needs a pitch raise and a second visit before the session anyway.
A piano tuned an hour before the downbeat is a piano that has not settled. A tuning done with the windows open, or right after a room has been aired out, is a tuning done at a humidity level the room will not be in during recording. If a room has been closed and unheated for a week, open it and bring it to normal condition a day early, then tune.
For a session with other instruments, agree the reference in advance. A=440 Hz is the default, but a track built around a fixed-pitch instrument, or a recording that will be layered against existing material, may need something else, and a piano cannot be nudged like a guitar once the players arrive. Getting that wrong costs the whole day. The records on the [credits page](/credits.html) run into this constantly, because folk instruments do not all agree with a pitch reference by default, and how that gets settled is part of how I work, described on the [about page](/about.html).
Does a piano in a Burbank studio need different treatment?
The tuning does not change. The schedule does.
An instrument that gets recorded is held to a standard nobody applies to a living room piano: unisons clean enough to survive a close microphone, a stable pitch across a full day of takes, and no mechanical noise that a condenser will pick up two feet away. That is a four-times-a-year instrument at minimum, and it gets checked before anything important.
Burbank makes the logistics easy in a way that matters here, because the Valley sits inside about 25 minutes of Glendale, Studio City, Pasadena and Hollywood outside peak hours. A tuning is a one to two hour visit, and a pitch raise plus tuning runs longer. Both are scheduled around the session rather than squeezed into it.
What to do with this
Booking a piano part in Burbank? Say when the session is and what the room has been doing, and you get the tuning scheduled two to three days ahead of it, plus an honest note on whether the instrument needs a pitch raise first or is fine as it stands.