The answer, in my opinion, is that it clearly can. At least, there are many people who put a lot of interest and emphasis in getting it, since the results may be worth it if the audio equipment is in line …
First, what does that mean for the living room? Conditioning it is to modify its acoustics, materials, objects and forms of the room, to achieve the ideal environment for listening.
What is the ideal acoustic environment for listening?
In theory, the ideal environment for playing recorded music would be an anechoic environment. That is, without any reverberation. So in this way, we would hear the exact reverb to that registered in the original recording, that is, the reproduction environment would not add any reverberation on its own.
This is very tricky to get, almost impossible. Achieving an environment that does not resonate with any frequency is so difficult, that laboratories, manufacturers and engineering studies have to build them specifically to even try to approach that goal.
To give us an idea, and to experience a similar sensation, in an improvised way, we can all try a good earmuffs.
Although reverberation is not zero, it is much smaller than almost any room. Thus we can imagine how it would be to reconstruct the acoustic environment in a way more similar to the original of the recording, by the absence of the reverberation added by our room of reproduction, this thanks to the use of headphones.
To look for this, would be the theoretical ideal in any room, listening room of a studio, etc. As we all know, reverberation colors and define the sound at different frequencies depending on the characteristics of the room, favors the installation of standing waves, distorts the recreation of the original sound space, etc.
Since this ideal of absence of reverberation can not be achieved, the important thing is to reduce it, to reduce the time of reverberation (the time it takes for the sound to completely vanish when the source of the sound ceases), and what is equally important, That time is similar to all frequencies. If it is not, we will have what is called coloring (warm rooms, cold rooms, etc.)f
The more we approach the goal of reducing reverberation, and achieving a similar time in all frequencies, the more accurate the original acoustic recreation. But this can also entail great inconveniences and difficulties:
– In a room with little reverberation, the orientation of the speakers, which must be located directly towards the ears, at the height of the head, in the typical position of the “regular triangle between loudspeakers and head” becomes more crucial. This is more critical the more anechoic the room, where the most directional frequencies would not reach the ears properly if the speakers are not directed towards us. In normal rooms, with reverberation and speakers not perfectly oriented, some of these frequencies reach the ear through reflections, but with a distorted spatial image, and all the cons that accompany the reverberation.
– We only hear the direct emitting power between speaker and ear. All the emissions in the other directions, disappears in the acoustic “trap” of the walls. This means that the loudness we perceive is much less if the room has less reverberation. Which is not bad, but we need a sound system more powerful than we would need in a room reverberating.
– If the room is very large, and we have conditioned it to reduce the reverberation to the minimum, can cause sensation of strangeness, even of dizziness! When people first enter the room. This happens because the brain sees a large room, but the ear does not perceive the reverberation that waits, the reverberation that anticipates according to the size of the room. This causes dizziness and bewilderment in some people. Imagine a large church, or a sports center, where a glass falls to the ground, or we throw a ball, and you do not hear a reflection at all … It tides and baffles the brain. In a small room, there is less chance of this happening.
– The most important thing is that the possibilities of reducing reverberation, and achieving an equal reverberation at all frequencies, that is, a flat response of the room, is almost impossible in a conventional room. We can achieve a reverberation time, for example of 0.25 seconds in frequencies of 10 KHz in a room, but to obtain the same thing in serious frequencies is almost impossible, since to attenuate and to absorb the frequencies serious they are necessary different mechanisms than those that are Use for high frequencies, and it is not easy to implement them in a room.
As we say, achieving this theoretical ideal of “no reverberation” is impossible in a normal room or room, and can only be approximated in anechoic rooms.
So, what can we do to improve the acoustic circumstances of a room or hall?
What remains, is to try to reach a compromise with all these vairables, to achieve the best intelligibility of the possible sound.
– Reduce the reverberation of the room.
– Achieve a more reverberative time between the different frequencies.
– Eliminate stationary waves as much as possible.
– Modify the acoustic environment to correct the position of our speakers.
– Optimize the perceived SPL, regarding the reverberation reduction of our room.
– Other variables, such as aesthetics and “HWHL” factor (Happy Wife, Happy life …)
With these goals in mind, each person has to decide what he can get, and what he wants to achieve, for his salon. One people will want to sacrifice the SPL they perceive, to get a better sound environment. There will be others who will not want to sacrifice space in order to reduce the standing waves, etc. This is where the hobby factor, the technical factor, the practicality, and the curiosity and eagerness to achieve a better result of the room to which we are accustomed come into play.
As a summary, you could say that there are different possibilities and techniques to reduce the reverberation of a room.
What you have to achieve is to reduce it, and also to be balanced. That is, in all frequency bands, the reverberation time is as close as possible, which will make the room flatter. It will not be worth reducing it in certain frequencies, and that there is great difference with others. The remedy can be worse than the disease: room more colored, fatiguing, excessively warm or cold, etc.
In order to reduce the TR, and to achieve balanced between frequencies, the ideal is to do it by means of technical procedures, with instruments of precision measurement, and different techniques that we will be able to see later.
But you can also pretend to approach it to the ear, investing time and experience.But what seems exciting, can become a difficult company, the more improvement you want to get. That yes, sometimes get subtle improvements, may not be so difficult, and worthwhile depending on the circumstances.
The objective is to absorb the sound that impinges on the walls, and that is transformed into heat. This is achieved through the use of suitable materials and resonators.
To absorb high frequencies, the most effective are the different materials and fabrics: Modify, add or remove: curtains, carpets, armchairs, absorbent foam, sound plates, etc.
Each material has different properties: for example, thick curtains absorb high and medium frequencies, some thinner will be limited to the higher range. Adding a heavy armchair can also help absorb low-medium frequencies, etc.
Always keep in mind that a material that we add or remove with a specific goal, will affect more things than we think. For example, adding a chair to reduce reverberation to mid frequencies will also reduce reverberation a bit at high frequencies, and that may unbalance our goal of achieving the same reduction of TR at all frequencies.
To absorb low frequencies, little will make absorbent materials and tissues. In this case are necessary resonator systems, double walls, pladur plates, etc. In this sense, there is a lot of what to talk about, that in future posts we will be able to see. But as an example of how difficult it is to absorb the low frequencies, it is worth that some studies construct double walls, even with architectural decouples between one level of the building and another, almost nothing …
To absorb the average frequencies, as everyone will imagine, is a compromise of the two previous situations: A thick absorbent will be better to absorb average frequencies than a fine one, since the latter will do a more localized work in high range of Frequencies.
As it is worth more a picture than a thousand words, here an example of panels of absorption of wool of rock, and the curve of absorption by frequencies given by the manufacturer:
INCREASING SOUND DIFFUSION
When reducing the reverberation to the maximum, and positioning the speakers in the exact and ideal point, it is impossible to obtain in any enclosure (that is not totally anechoic), the objective is focused on getting a good diffusion to avoid the focused reflections that detract from the Recreation of the original sound space, and also, to optimize the Level of Sonority with respect to the recreation of sound.
This is achieved by sound diffusion. The diffusion consists in modifying the path of the reflections and dispersing them in a more natural way than the one that occurs in a square room of flat furniture …
To achieve this, there are very complex diffusers, calculated on the basis of MSL mathematical sequences of randomness, which despite being elements that can be installed on flat walls, get very random and natural diffusion at certain frequencies:
A simple and homemade way of beginning to improve the diffusion, is turning the environment of our room into something more complex and intricate for the propagation of the sound. Adding ornaments, figures, crystallites hanging from the lamps … All kinds of solid objects that diffuse sound at different frequencies, provided it is done with clear objectives. There is a world also within the scope of sound diffusion, and soon we will have the opportunity to talk about it as well.
As an example, which some of us may have noticed on the spot, let us think of a Romanesque church, with its smooth walls, and simple and diaphanous forms, against a baroque church, with all those twists, detail and relief in ornaments and architecture . Imagine the sound inside. In the first it will be more reverberant and cavernous, and the voices will be understood worse. In the second, in the baroque, it will be more natural, less focused, more balanced, thanks to its complex forms better diffuse the sound and help its absorption.
Another aspect to be improved in a room, if we do not get an anechoic room (which as we have seen, it will not be …), is the reduction of standing waves.
What are the standing waves?
It is the installation of reverberation of the sound between parallel surfaces, that by constructivity and acoustic destructiveness, provoke valleys and peaks to certain frequencies (own modes of each room), and they make that the color is colored of different form depending on the site in which we Let’s locate the room .
This problem is one of the most detrimental when it comes to reproducing sound in enclosed spaces, and with which we all live almost without realizing it.
It is very harmful, because it is not easy to correct it in a room, and because its coloring, although often not remarkable, damages the sound result, both in valley and peak points, as we move around the room. Depending on where we are in the room, the room response has different irregularities.
They usually affect medium and low frequencies, since the wavelengths of these frequencies are the most typical of being installed between the walls of rooms and rooms.
About this there is a lot of miga too, so here we have more pending issue also for the future.
The way to reduce them, is to avoid that these waves are installed between parallel walls, and to achieve this there are two ways:
– Absorb the sound on the walls, so that it does not come back and install itself against the opposite wall. Which is difficult as we say, because of how difficult it is to get low frequencies absorbed in a room. This aspect has better the rooms that have walls of plaster, etc., that make the function of resonators. In these fortunate cases, the wallboard may favor less the creation of standing waves than a rigid wall, but it may also be that the frequency of absorption is not what we need to reduce. Although in general, a room with walls of plaster, has better conditions in this aspect.
– Break the parallelism between walls. This is the ideal. If there are no parallel walls or ceiling / floor, these waves can not be installed (which is the cause of the standing waves), and they end up moving around like other waves of all other frequencies. Many have seen many cinemas or auditoriums with the walls in the shape of a wedge or angle. Well, the objective is this, to reduce the parallelism between walls, floors and ceiling, and to avoid the installation of standing waves.Hence in some good cinemas, the reproduction of serious sounds is quite clean (apart from all the other things well done that can have the cinema in question)