Acoustic treatment of a bedroom while listening to music

A bedroom is the most inconvenient room for serious listening. The bed is against the wall, the wardrobe opposite, a window on one side — it's almost impossible to achieve a symmetrical seating arrangement. At the same time, the request to 'listen to a record before bed in the evening' comes to us consistently: in 2025, there were 14 such orders, 9 of which were specifically bedrooms of 14–22 m².

Let's break down what really works, step by step.

Why a regular bedroom sounds bad

Soft bed, carpet, thick curtains, pillows — all these absorb mid and high frequencies. But the bass has nowhere to go: a 50 Hz wavelength is 6.8 meters, it calmly wanders between the walls of a 4-meter room, forming standing waves. The result is an imbalance: no highs, bass hums on one or two notes.

Last year, we measured a 16 m² bedroom for a client in Zelenograd. RT60 at 4 kHz was 0.22 s (dry, like in a studio), and at 80 Hz it was 0.91 s. A fourfold difference! Any jazz bass in such a room turns into a monotonous hum.

The impulse response — Dirac's function — immediately shows this picture: the spectrogram reveals “tails” at modal frequencies that last three times longer than they should. The standard Thiele–Small method from 1965 with sine signals will not show this; its efficiency in a real room is 1.5–5%, whereas the impulse response provides full correlation with what the ear hears.

Where calculation begins: 3D scan and modal analysis

Before any treatment, we perform 3D scanning. This is not a whim — without precise geometry, it's impossible to calculate the room's natural resonances (modes). The formula is simple: f = 172 / L, where L is the side length in meters. For a typical bedroom of 3.5 × 4.2 × 2.7 m, the modes fall at 49, 41, and 64 Hz — right in the main range of the bass guitar and kick drum.

After the scan, we count three things:

• Modal map along three axes – where pressure peaks and dips will be;
• Required absorption by bands 63 / 125 / 250 / 500 / 1000 / 2000 / 4000 Hz for target RT60 ≈ 0.3–0.4 s;
• First reflection points from side walls, ceiling, and floor relative to the seating position.

The target RT60 for listening to music in a 15–20 m² bedroom is 0.30–0.35 seconds, flat across the entire range from 80 Hz to 4 kHz. This is much more difficult than just making it “dead”.

What do we install: bass traps, diffusers, spot absorption

There are three critical zones in the bedroom.

Corners — for bass. Corner bass traps 40–60 cm thick made of mineral wool with a density of 40 kg/m³ with a mandatory air gap are used here. Without a gap, the trap loses 30–40% efficiency at 60–80 Hz — this is not our hypothesis, these are measurements from two dozen objects. We hide the traps in a cabinet niche or in the bed podium so that the bedroom does not turn into a studio.

First reflection points – for the mid-range. Side walls at the ear level of a sitting/lying listener. Thin panels 5–8 cm thick with fabric upholstery work here. They can be integrated into the headboard of the bed — we had a project in St. Petersburg, on Krestovsky Island, where we covered the entire headboard with acoustic felt with a pattern — the guest would not guess that it was a treatment.

Rear wall — for diffusion. If the listener is sitting on the bed, there is usually a wall with a wardrobe or paintings behind them. Diffusers are needed here — two-dimensional Schroeder or skyline diffusers. They do not muffle the sound but disperse it, preserving the 'air' in the recording. Without diffusion, an over-treated bedroom sounds dead, like a closet.

What to do if the renovation is already done

The most frequent request: “everything is ready, can we add something?”. Yes, and quite a lot.

We disguise corner traps as floor lamps or hide them behind full-wall curtains. We replace the headboard with an acoustic one — it doesn't look like a modification at all. On the ceiling above the bed, we install a cloud made of perforated plasterboard with mineral wool behind it. One of our clients in Kazan made such a cloud with perimeter lighting: both acoustics and a night light.

Sometimes the client is categorically against any visible panels. In such cases, we use “hidden” treatment: niches behind curtains, acoustic ceilings, special furniture filler. It's 30–40% more expensive, but visually you won't notice anything.

But what you definitely shouldn't do: glue foam “pyramids” from a hardware store. They only muffle the highs (4–8 kHz), while the problem in the bedroom is in the bass. You'll get an even brighter and more unnatural sound — proven by dozens of reworkings after “DIYers.”