ACOUSTICS AND HIGH-END AUDIO

Jorge Knirsch

Introduction

In the last few years I have studied the area of acoustics in depth,  trying to learn how to apply it to most varied environments that exist. I attended several courses for this, I have collected and read many imported books on the subject and I have purchased various measuring devices too, just to carry out the practical part of our Acoustics and Audio Laboratory. In this lab we have set up the acoustic equipment and made the acoustic measurements needed in order to obtain an objective assessments of our results.
         I want to invite once more all those interested in sound and music to come and visit us and to see first hand the experiments we are doing. We are right now giving classes on the electrical aspects and musical perception of acoustics at the Omid Bürgen Studios.
        Acoustic’s influence in audio reproduction has been shown to be fundamentally important. Its importance continues to grow in such striking ways, as we deepen our studies, encompassing more details. Today we ascribe to it the most important portion of any reproduction of sound. We can say this, if we keep in sight that the room is decisive for low-frequency reproduction, that is, bass sounds, influences about 80% of the final outcome. Yet for high frequencies, the room’s influence is as important as the sum of all remaining factors put together; in other words, it equals the influence of the electric system plus grounding in addition to the electronic equipment. Acoustics attains such a highlighted position in sound reproduction that those not willing to take it into account will already have got lost somewhere along one of the “pine branches” from the lower part of the "audio pine tree"!!! Any conclusions, analyses, assessment of equipment or other aspects of the sound made without taking accoustics into account may be deeply mistaken in this situation!!!
        In this new series we start here, our goal is to show you the importance of acoustics, the reasons why so little is said about it among us, mainly on the audio/video media, and why its principles are so little spread about. We also have the intention to circulate technical information, in order to start a discussion around this topic, so that we may raise our level of understanding and we may all grow together. The intention is also to better a room's quality level, mainly in studios and through technicians, Brazil-wide. Therefore, from this viewpoint, any information and contribution from you, our reader, is  welcome about the subject. Our e-mail is still at the disposal of all: jorgeknirsch@byknirsch.com.br

© 2004-2008 Jorge Bruno Fritz Knirsch
Todos os direitos reservados
http://www.byknirsch.com.br

What is the Widespread Opinion on Acoustics?

Acoustics is a subject of amazing diversity, and the opinions about it are just as varied. In truth, most people haven’t even heard about acoustics. This majority is made up mostly of young people who wish to set up a system at home for listening to music and watching films. That is usually how people get started. Nowadays, a young person's greatest wish, no doubt, is to set up their Home Theater. And in setting up this first Home Theater, what matters most to the beginner is the equipment he or she will have to purchase and install. Advertisements or articles help them with the choice, making suggestions about equipment that don't always present the best cost-to-performance ratio, many times due to the editor’s lack of knowledge himself, or due to the power of those who advertise.
        Little does this young person know, our new Home Theater (HT) owner, that the room where they are setting up their HT is crucial in determining the final listening results they will be getting and listening to!!! As we have said before, this room, including its dimensions and everything inside (doors, windows, draperies, carpets and furniture in general), will exert greater influence in the system’s final listening result than the influence due to the actual sound quality of the purchased equipment. In fact, taking this to extremes, we realize that even building material exerts an influence. Looking at this same fact from a different perspective, we can say that the accoustics of an untreated room is one more instrument playing on our recording, albeit, not one that you can specifically identify as such, but one which has a special quality to alter the original instruments and voices, and thus altering as a consequence the tonal balance and soundstaging of the musical performance. As one popular saying goes: The room sings along!!! But our young HT owner still doesn't know this and perhaps will not find out very soon.
        Other more experienced people have heard of acoustics but still haven't  figured out the scope of its importance. For this reason they don’t give it much value. Partly because they never heard the beneficial effects a treated room can bring because there are few well-treated rooms to be found and  which can be visited.
        Likewise, many of us may even possess excellent systems, but the listening room is and will remain untreated. The majority of music lovers and audiophiles in general find themselves at this point. I myself spent nineteen years listening to music and assigning little, if any, importance to acoustics, and never imagining its magnitude and depth. It is here also that the majority of equipment exchangers find themselves, always replacing everything and never getting anywhere!! They are always unhappy! They are lost out there on a “pine branch” trying to reach the top. However they can only just reach the tip of the branch where they are and nothing else!! And unfortunately, they don’t realize this many times!!
        It is also important here to mention that the media, and mainly the press, speak very little about acoustics, for it is more interested in selling equipment than in providing technically correct solutions in order to have good listening experiences. Many of the magazines that indeed test audio equipment, handing out so-called audiophile opinions, don’t even possess adequate rooms for this, and end up by assigning, to the equipment under scrutiny, the characteristic results from such badly treated rooms. The media hasn’t been of help really; quite the contrary, it has created a vicious circle from which many cannot escape, and who become misguided and spend lots of money replacing equipment. It’s an endless circle !
        Other people, because of their spouse, don’t manage to change room acoustics. Even though they know it is possible to carry out very good-looking acoustic treatments, a spouse many times isn't able to convince their significant other about these possibilities, and an acoustic project doesn't advance. I think that only rooms dedicated to this purpose advance in these situations, but isn't always possible to separate a room like this.
        Others think that acoustic treatments are very expensive and don’t invest in them for this reason. For these, it doesn’t make sense to spend more on acoustics than on the equipment itself; something not always necessary. They think it would really be a misuse. I know many among us owning systems that come close to the million dollar figure, and yet they don’t have their rooms treated!! These systems don’t perform as they should in general, due to an untreated room!! They remain way below their full potential. And many reach wrong conclusions, saying that expensive equipment is not worth its cost. Big mistake!! Notice how many technically groundless concepts and premises appear in our field for this reason!
        On the other hand, the professionals present wide ranging opinions but there doesn't exist agreement between them on this subject, therefore consumers end up with a lot of insecurity. One of the reasons for these disagreements is perhaps the large variety of existing rooms, such as concert rooms, opera rooms, auditoriums, theaters, churches, halls of worship, meeting rooms, and recording studios that exist, and even within this category there are several versions, such as studios for voice and for several instruments, mixing techniques, mastering rooms, Home Theater rooms, listening rooms and balanced listening rooms (BLR), among the many others. Each of these environments has a specific acoustic goal and consequently they also need different solutions, which not all acoustic technicians have the background to master.
        The fact is that there is much confusion in the field. As a result of this situation, very little is said about acoustics, partly because of ignorance and partly for experts not being willing to disclose “acoustic secrets”. As a consequence, the general quality level of our rooms could  be bettered.
        I’m sure I forget to mention several other aspects and opinions that exist in the market. However, ignorance is big in this area and those who know a little bit about the subject keep it a big secret, not realizing that  he probably holds just a small part of the big picture and that perhaps he  is becoming technically out-of-date.

Acoustics: Technique and Listening

Acoustics is the part of physics that studies sounds: their generation, transmission, isolation, reflection, refraction, absorption and diffusion. Sounds are sound waves that propagate by physical means, carrying information in energy form!! There is however another subject, psychoacoustics, which studies the  perception of sound, searching for that which most pleases our human ears. These two subjects clearly go together, where technique tries to offer us the best listening solutions for each room type and each of them for the most varied applications.
        Our intention here will be to present the small portion of knowledge we have acquired these past few years and which we have always been trying to update, aiming at providing an effective contribution for the betterment of our auditionings. Far be it from us to have the pretentiousness of exhausting all issues. The change in this area is so fast-paced due to the enormous magnitude and the variety of knowledge that is encompassed by acoustics, and also the bewildering progress of scientific knowledge in this area that causes it to be hard to follow.
        In this series, we intend to assign more importance to critical listening rooms and recording techniques, mastering rooms, and of course, Home Theater rooms, which are becoming more fashionable today; all this grounded in the theory needed for the good understanding of the concepts we will try to present along these articles. I make here a recommendation for those who will follow me in this new journey, and it is that they have a look at the optics section in their schoolbooks from high school, also trying to review pressure and logarithm concepts. These three topics have much to do with acoustics and we will use them here.

Conclusion

In this first article, we began a new, never-before-published series on acoustics. We intend to present the theoretical base needed for the understanding of the subject, showing then in practice how to apply acoustics to our critical listening rooms. We’ll make use of our technical knowledge for this, as well as all the experiments carried out on our Acoustics and Audio Laboratory. We will use many sites from the Internet, so that we are not repetitive and in order that we may preview subjects.
        All our considerations will mostly be focused on balanced listening rooms. These are in fact the rooms that all of us should have had treated in order to savor our listening experiences, and so that we correctly  assess our equipment.
        To start, I wish to suggest you type in the words “sound waves” on the search site http://www.google.com/ , and have a look at all the topics that appear there. Be very careful when reading the theoretical subjects because there are many technical mistakes on these topics.
        We don’t have the pretentiousness here of exhausting the subject, since our knowledge is also limited, but I’m sure we can give our contribution for a meaningful betterment of listening rooms. See you next time, and warm regards!
            I wish a hi-fi, listening experience to all!

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