What acoustic solutions should you buy for your cinema?

Cinema has become increasingly important in the lives of many French people in recent years. So, some are taking the plunge and building home cinemas. Acoustics is, certainly, the most important parameter to obtain good sound quality.

Acoustics, a broad concept

The notion of acoustics is a broad notion which mixes several different sub-concepts. Thus, it encompasses the notion:

1. Insulation

2. Reduction of reverberation

Insulation

Acoustic insulation refers to all the techniques aimed at reduce the propagation of sound between two spaces. Its aim is to limit noise pollution which can affect the comfort and health of the occupants of a building.

For example, if you are near a road, good sound insulation will prevent you from hearing road traffic noise.

Acoustic insulation is based on two main principles:

1. The law of mass: the heavier and more compact a material is, the more it slows down sound waves

2. The mass-spring-mass law: this consists of inserting a “spring” material (e.g.: glass wool, sheep wool, etc.) which absorbs vibrations between two masses (e.g.: placo)

Reduction of reverberation

The reduction in reverberation corresponds to attenuation of noise emitted within a confined space. This is so that there is no hubbub and/or good quality musical reproduction.

If you have a room with a low reverberation time, then you won't need to concentrate to understand the words of someone speaking in that room. Conversely, if there is a lot of reverberation, a cacophony phenomenon can occur.

Why do professionals talk about diffusion and absorption?

Acoustics professionals talk about diffusion and absorption because these two phenomena are essential for controlling and optimizing the sound environment of a private cinema.

Sound absorption

Sound absorption is a technique for reducing reverberation in an enclosed space. Ultimately, this reduces the overall noise level.

To optimize the acoustics of a private cinema, this is the first type of acoustic treatment to carry out.

The diffusion

Acoustic diffusion seeks to evenly distribute sound waves in space. This in order toimprove the clarity, liveliness and homogeneity of sound.

After having obtained an interesting reverberation time for a private cinema (around 0.6 seconds over a wide frequency spectrum), it is possible to use diffusing products to obtain better immersion in your films.

Should an acoustician take acoustic measurements?

Taking acoustic measurements is not essential in all cases. If your room is less than 50m², the software used by the specialists will be very reliable. So, there is no need to pay for expensive measurements. Rather favor an investment in diffusers or a bass trap with the economy of taking these measures.

For larger pieces, this may be of interest depending on the specifics of your piece and your expectations in terms of result.

What are the acoustic solutions on the market?

It is possible to differentiate 5 main families of acoustic solutions on the market. Depending on your budgetary and decorative constraints, you can opt for:

1. Acoustic foams

2. Acoustic panels

3. Stretched canvases

4. Acoustic diffusers

5. Bass traps

Acoustic foams

Offering good value for money, acoustic foams are widely used in home theaters.

Often petrosourced, this is where the problem lies. Likewise, they are used less for projects that are intended to be aesthetic.

Acoustic panels

More expensive, but more effective and aesthetic, acoustic panels are another solution for reducing the reverberation time of your private cinema.

Indeed, many products have an alpha sabine of 1. This corresponds to the best possible performance, from an acoustic point of view, on the market. Be careful, however, to ensure that this alpha sabine is obtained in the same circumstances as your use (is there a plenum? Is the panel placed horizontally or vertically?, etc.).

Stretched canvases

Stretched canvases are widely used in private cinemas. However, make sure the canvas is coupled with insulation. Alone, its effectiveness will be very limited.

Likewise, favor dark colors to avoid light pollution.

Acoustic diffusers

Acoustic diffusers will be used in projects with a little more budget.

As seen previously, they bring a real plus to the immersion in your films.

Bass traps

If your room has a low frequency problem, you may need to use a bass trap.

Indeed, foams, canvases and acoustic panels make it possible to treat medium and high frequencies. Conversely, a bass trap is designed specifically for low frequencies.