All about acoustic diffusers

What is the role of an acoustic diffuser?

 

We already discussed a great deal about the treatment of the basses and the dampening of the echo. Indeed, these are the most frequent acoustic issues, however, we will fail to achieve the perfect sound if we concentrate solely on these issues.

 

Diffusers also have a great importance in the acoustic design, i.e. the acoustic treatment, certain issues can be solved only by applying them.

The two most common acoustic issues, regarding which our customers turn to us

Most of the professional requests we get originate from the following situation: the client purchased the longtime desired and carefully selected Hi-Fi or home theatre equipment, but even after adjusting all possible parameters, he or she still have not managed to achieve the desired sound quality.

But when the client listened to the equipment at the store way back then, the equipment produced the sound of his or her dreams. As a matter of fact, in most of the cases, the issue is due to one of the two effects explained below.

Over dampening of the high frequencies, lack of  sound acoustic diffusers.

In one case the importance of acoustics was not unknown for our client, who started the acoustic design with homemade units based on information found on the Internet or recommendations by friends.

One should be aware that due to their density, acoustic foam and the Styrofoam are inappropriate to absorb or scatter low frequencies. However, they can mitigate high frequencies, therefore, they seem to be effective in the first case as they reduce the reflections of high frequencies.

Despite of the efforts, our customer realised later on that the result is contrary to his original intention and concept:

• increased strengthening of bass notes,
• distortion of the basses,
• unwanted echo, where he didn’t hear the real amount and quality of low frequencies but the sound of the room.

Dampen the echo!

At this point we arrived to the second most common problem. Despite of the well installed music equipment, we hear a strong echo that spoils the pleasure of watching movies or listening to music.

At this stage of disappointment, some client already turn to us asking for help to design acoustics, but many of them rather try to find some home-made solutions, and purchase some “absorbers”. And only after this they ask our help for the below mentioned reasons.

 

However, the home-made solutions are “over successful”, i.e. the absorber absorbs the sound waves, but certain frequencies can be over dampened, which again makes the listening to music or watching movies unpleasant.

 

The above-mentioned cases show that sounds not only need to be absorbed, but also to be scattered. In order to get a clear, dynamic sound without echo we also need sound diffusers.

 

 

Professional acoustic measurement and design instead of homemade solutions.

Instead of home-made solutions we can spare time and money if we entrust a professional with the treatment of acoustic issues. In the course of acoustic measurement, depending on the parameters of the room, we can specify which type and how many acoustic panels do we need, and where we should place them in order to achieve the desired sound quality.

How do sound diffusion work?

You have certainly experienced the phenomenon of gradually decreasing echoes in parallel with the furnishing of the room.

The reason for it is that furniture fittings do act as diffusers. In case of acoustic diffusers, we can calculate their diffusive impact before their implementation, therefore, diffusion effects can be planned and calculated.

Acoustic panels have irregular shapes, thus they can divert the sound waves reaching them, and can scatter them within the room – since they reflect the waves in a different angle than the walls do. It can be observed that diffusers are composed of units with different depth.

Despite of their irregularity, the surface of diffusers is well designed: they
reflect different frequencies in different directions.

The denser the material they are made of the lower the frequency they can divert.

• direct echoes are reduced;
• improvement in sound details and vocal clarity;
• pleasant, natural sound is achieved;
• without creating an anechoic chamber, the spaciousness increases.

2 in 1: what can a soundproofing panel with
diffuser offer?

Within our product range, besides diffusers, we offer acoustic panels with a diffuser. These are acoustic units, to which a diffusing face plate is installed and, thereby, it can absorb certain part of the frequency range, while it can reflect some other frequencies at the same time.

It means that it has a reflecting, scattering impact similar to diffusers.

Compared to broadband absorbers, it absorbs more low frequencies – below 300Hz – but less high frequencies – above 600Hz. In that way it ensures that high frequencies won’t be over damped in the room.

Perfect Acoustic – comprehensive acoustic solutions with Sound diffusion.

Judging the sound quality is indeed a subjective issue. Some people like the sharp highs, others prefer bass tones or buzzing basses.

Whatever group we belong to, we can be sure of one thing: if we concentrate exclusively on audio equipment and cables in order to achieve the ideal sound experience, we will be disappointed.

In such cases the solution is not to purchase new equipment constantly, which are believed to be better and to have higher quality. We can reach our goal by eliminating the distortions existing in the room. Acoustic measurement, design and acoustic items produced by us can help you to achieve your goals. This is what we call treating acoustics or in an other word the “acoustic treatment”.

It is true that ceilings, walls, windows…, etc. also function as sound-reflecting surfaces, but due to their flat, hard surface, all sound energy is reflected back in the same direction, and are concentrated, so the sound will be echoing, and become unpleasant. Acoustic diffusers on the other hand, thanks to their irregular surface of different depths, radiate the energy of the sound into smaller parts, distributing the sound more evenly, thus creating a more balanced, more spacious acoustics.

It is important what material we use:

The material of diffuse surfaces is not a negligible aspect either. Hardwood, which has excellent absorption abilities, is generally used as the raw material for sound-absorbing and diffusing devices. Acoustic cotton, acoustic silk, or imitation leather also have effective sound-absorbing and scattering properties. For acoustic purposes, high-density but flexible and fibrous materials are suitable. Therefore, cellular Styrofoam elements or egg boxes are not suitable for acoustic design; the latter are only good to catch the dust… The higher the body density of a material, the better its sound absorption capacity.
It is not necessary to cover the entire surface of the wall or the ceiling, only the primary reflection points must be covered with diffusers. These points can be determined by acoustic measurements.

The diffusers can also be placed on a wall or ceiling, or even on the floor (with folding legs).
You can order several colours, patterns, sizes or designs. Thus, not only do our diffusers perform to the maximum in the acoustic field, their aesthetic design allows them to be decorative for any style of room.

G.H.

 

Written by Róbert Polgár