http://www.audioholics.com/education/acoustics-principles/rss.xml What happens when you get your room so tight that no one can hear you scream? Should I use 2-inch or 4-inch thick Owens Corning insulation for my absorbers? Do I need reflection or absorption? We'll address all of these questions and more with a comprehensive acoustics section that goes over room isolation, reverberation, acoustical materials, and more. hourly 12 2006-12-01T00:00 http://www.audioholics.com/static/logo.jpg http://www.audioholics.com/ http://www.audioholics.com/education/acoustics-principles/twenty-questions-toward-a-correct-room Let’s get right to it. You love audio, are passionate about your system and are always searching for a better experience, a more accurate response. You’ve heard the term “room correction”. You’ve heard speakers in various rooms, you are aware of acoustical treatments and active room correction systems (ARC). You know that your dedicated audio system is not in a purpose built room. You would like to make the room as “correct” as possible; however you have no clear idea what approach is best for your room. This article explores the 20 questions you should ask yourself towards building a great room along with feedback from leading industry experts within their own respected disciplines on this topic. Jeff Hedback 2007-12-09T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/building-great-bass-response-in-your-home-theater If you are searching for the utmost listening experience in your room with your system it is time you consider how your space is constructed. It is the purpose of this article to show you how the construction relates to your audio experience. There is an inverse relation between sound isolation (STC) and sound absorption (NRC). The greater the isolation of a surface the more sound energy is going to remain in that space. This applies directly below 200 Hz where the resonance of room modes is a primary factor of your systems character. It becomes compounded when you add multiple sound sources with low frequency information…you got it, your room. Jeff Hedback 2007-05-20T23:47:22+00:00 Editorial http://www.audioholics.com/education/acoustics-principles/early-reflections-in-home-theaters-a-different-perspective Early reflections may or may not be major problems in home theaters. Addressing them through the use of heavy absorption should be pursued with caution. I believe the issue of early reflections and their relative merits (or lack thereof) in any home theater should never be ignored. This article opens a dialog on how to best deal with them and how they differ from large listening spaces. Jeff Szymanski 2007-04-11T10:14:05+00:00 Editorial http://www.audioholics.com/education/acoustics-principles/better-sound-through-active-room-correction-a-primer-to-audyssey-multeq-pro Audyssey's Sound Equalizer is the company's first branded, flagship statement product. In working with the MultEQ Pro software over the last couple of months it has become apparent to this author that the ASE's power and flexibility can be best exploited, as far as overall system sound quality and balance are concerned, if careful attention is first paid to speaker selection, placement, and positioning. Often, passive room treatments, themselves carefully selected and placed are also recommended. Patrick Hart 2006-10-01T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/haa-level-i-certification-training-course-overview This article is about HAA certification training and it also contains some great information on home acoustics from the course which I have included in this article. You may find that even a few tidbits of information can make drastic sonic improvements to your system. ken 2006-06-28T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/a-new-way-to-think-about-room-acoustics I often have people ask me some very basic overall questions about the acoustical design of a room, such as: how much will it cost, what will it look like, how much better is it going to sound? All of these are important questions and sometimes it's difficult to give someone an answer that's easily understood. rives 2006-05-07T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/designing-a-listening-room-rives-audio This article should provide a good understanding of what can be expected in terms of the process of designing a listening room. There are five phases to most design projects. Some of the phases may overlap slightly on occasion, but ideally each will have a clear beginning and ending point. rives 2005-06-29T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/human-hearing-reprise-part-4 That it has evolved into an extremely sophisticated psychophysiological function should come as no surprise when one considers that in nature, the perceptor possessing the superior hearing mechanism/process is rewarded with survival. It's this same formidable sophistication, forged over time in the harsh crucible of simple survival that allows us now to experience the sublime joys of music - live or reproduced. mark 2005-05-02T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/human-hearing-distortion-audibility-part-3 Distortion. Present in every electro-mechanical-acoustical transducer ever built, yet infrequently does one find information (let alone useful information) that describe the type and degree of distortion presented by the transducer. Head out on the Internet and corral a good sized collection of loudspeaker driver spec sheets and you'll find that not many will offer much guidance where it comes to sizing up candidates for your next loudspeaker system design. That is, if you include distortion figures amongst the criteria used in rendering your component purchase decisions. What to do? mark 2005-04-23T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/human-hearing-phase-distortion-audibility-part-2 Given all the foregoing research presented in various academic, scientific & industry journals, as well as other media, variously indicating the audibility of phase distortion, there remains no valid doubts regarding the existence of phase distortion. mark 2005-04-07T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/human-hearing-amplitude-sensitivity-part-1 The human ear has been held by armchair acousticians and physicists as The Ultimate Microphone Ever Created. I suppose in a superficial way that sentiment has, at first glance, a satisfying ring of truth to it. Reality, though, holds a different opinion. Truth is there are today microphones that can, with ease, outperform the human ear. Where the ear may, however, lay claim to the ultimate mic award is when it's considered in combination with the post-processor to which it is hard wired, namely, the human brain. Now there is one formidable combination! mark 2005-04-05T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/a-guide-to-sound-isolation-and-noise-control This is a very appropriate saying with regard to sound isolation. We are often asked questions like: "What can I do to this wall to stop the sound going through to the bedroom on the other side?" It's almost incomprehensible to people that the wall may not be (and probably isn't) the only part that is leaking sound to that bedroom. The other parts might well be the floor, the ceiling joists and other shared walls. You could make changes and increase the STC (Sound Transmission Coefficient) dramatically for that wall, but the result might be marginal because the majority of the sound is getting through elsewhere. rives 2005-03-27T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/room-acoustics-isolation-noise-control Our first three courses in the CEDIA Seminars series covered proper system calibration after installation and set-up was complete, followed by two complementary courses on room acoustics. More often than not, however, a great home theater must be capable of co-existing within the framework of the day-to-day goings on in the rest of the house and its occupants. This is where an understanding of how to isolate your home theater so as to control the inevitable noise leakage of dinosaur foot falls and anti-aircraft guns in the rest of your home's living space can be a really good idea. Patrick Hart 2005-01-25T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/audyssey-labs-multeq Tom Holman had a problem. As Professor of Film Sound at the University of Southern California's School of Cinema-Television, one of Tom's duties was to set-up, calibrate and acoustically equalize Norris Theater. This minimum five hour job was a step-by-laborious-step of set-up and reconfirmation of settings done months before. Inevitably, recalibration accompanied by more fine-turning was always required to make each channel of the Norris Theater system perform optimally. Norris was but one of literally tens of theaters and studio facilities that Tom has been calibrating manually for many years. Patrick Hart 2004-12-29T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/the-perfect-room I get asked "What is the perfect media or listening room?" quite often. My response is usually something on the order of "It depends." And that's very true, it depends on a lot of things, but mostly it depends on the client. There are so many facets that go into the listening room, and the most important is the desires of the client. I have a pretty good idea of what my perfect listening room would be like, and I can almost guarantee that it would not the same for many clients. Most people are surprised by my answer. The say, "No, come on, really, what's the perfect listening room." So, I have to explain to them, how it is different depending on the desires of different people. I decided this would be a good topic for this month's column. clint 2004-12-06T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/room-acoustics-acoustic-treatments Anthony Grimani's "Room Acoustics: Acoustic Treatments" class followed his course on "High Performance Home Theater Calibration" on the afternoon of my first day at CEDIA. I'm reviewing it here, as the third installment of our CEDIA Seminars because it flows well and builds upon John Dahl's "Acoustics 101" course. A CEDIA System Designer-in-training would normally take these two classes in this sequence so that is the order in which we are presenting them. Patrick Hart 2004-10-25T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/acoustics-at-trade-shows After a summer break, it's back to acoustics. I had intended writing on DIY and some basic room set up tips. However, that's going to wait until next month. I am just returning from the Denver Audio Fest. This was a really great show in my opinion. It was not crowded as it was the first year and you could go into the rooms and listen to your heart's content. Most of the rooms were 2 channel. There were many high efficiency, low power SET rooms (typically horns). But, there was a nice display of solid state and more mainstream loudspeakers as well. In other words, it wasn't a "glass" show, but rather a very nice and refreshing mix. clint 2004-10-20T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/acoustics-101-course-by-john-dahl-of-thx John Dahl has been a volunteer instructor for CEDIA for the last 11 years. So it's a pretty good bet that virtually all of the CEDIA design and installation professionals who have passed through his classes have been taught Home Theater theory, design and calibration from the perspective of THX's recommendations. Patrick Hart 2004-10-04T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/high-performance-home-theater-calibration The Custom Electronics Design and Installation Association (CEDIA) was founded in 1989 in recognition of the increasing complexity of integrating audio and video systems into the home environment. Coincidently, Dolby Pro Logic was gaining solid momentum in 1989. Pro Logic was a four-channel system with five speakers; left, center, right, and two rear mono surrounds. In retrospect, the change from the previous three-channel Dolby Surround, which had no center channel, was profound. The addition of a center channel marked the first true step in the convergence of audio and video. And the founders of CEDIA recognized that a new and more complex world had emerged. Patrick Hart 2004-09-30T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/helmholtz-resonant-absorber A listening room, defined by its dimensions, can be mapped in terms of a series of pressure peaks and nulls, in all three dimensions. This refers to the creation of standing waves (modes), and the resultant sonic characteristic of the room at modal (essentially bass) frequencies. There are other considerations, such as the boundary effect, but this has less to do with specific modal treatment, and more to do with generalised treatment, and certainly with loudspeaker and listening position placement. Adam P. Salisbury 2004-08-31T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/calculating-room-modes-with-modecalc ModeCalc can help you design a new room that sounds as good as possible, or predict the low frequency behavior of an existing room. This tutorial explains the basics of room modes, and tells how to use ModeCalc and interpret its results. This text is also available as online Help when you run the program, so there's no need to print this page separately. Ethan Winer 2004-08-31T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/acoustics-facts-and-fiction In 1979 TEAC introduced the 144 Portastudio, and the recording industry hasn't been the same since! In those days a decent limiter cost nearly $1,000 and a good spring reverb unit would set you back more than $2,000. We can all be grateful that very high quality audio gear is now available for even the most modest budget. But one important feature still distinguishes a state of the art recording facility from most semi-pro and project studios: real acoustic treatment, especially bass traps. Ethan Winer 2004-08-31T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/physics-tutorial-2-the-physics-of-hearing The first thing we should understand about sound is that it is a mechanical wave. Any mechanical wave is a disturbance that travels through some material or substance, such as air, called a medium for the wave. Sound waves can travel through any kind of gas, liquid or solid medium. Mike Duda 2004-08-30T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/rooms-without-boundaries-using-rpg-diffusors This month we have another guest writer, Jeff Madison from RPG. Jeff is the senior product application consultant in RPG's Home Theater Division. He spent his first years at RPG developing its computer modeling and acoustic testing capabilities. With a background in music and engineering, he enjoys the challenges of both large and small spaces...and golf. Jeff Madison 2004-08-25T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/bass-traps-not-just-for-fisherman If you ask most audiophiles to describe the main acoustic problem in their listening rooms, they'll probably tell you there's too much ambience and echoes. Or perhaps they'll report that stereo imaging is poor, most likely due to early reflections off the side walls and ceilings. Indeed, everyone "knows" that to test the acoustics of a room you simply walk around and clap your hands while listening for reverb and echoes. But to my way of thinking a far more important problem occurs at low frequencies, and you'll never hear that with hand claps. Let's first take a step back and consider the bigger picture. Ethan Winer 2004-08-25T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/getting-the-right-acoustics-for-your-listening-room "The room is the first thing we start with and the last thing we think about." This statement is so often true. It's unfortunate because the room, as we often refer to it as the "invisible component" can easily make or break the system performance. Think about it, an amplifier company makes a state of the art amplifier capable of reproducing a signal with no more than 0.01 Total Harmonic Distortion, dynamic headroom above 110 dB, and gold plated connections to insure the best possible path for the signal. Then we put this amplifier together with speakers and other fine performing electronics into a room that delivers a bass boost of 12 dB at 80 Hz, a huge dip at 300 Hz, and another strong peak around 5 kHz to 10 kHz. rives 2004-08-25T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/room-modes-and-dealing-with-them When the boundaries of a room accentuate bas frequencies, the listener's perception is one of a reduced midrange and soundstage. If you don't get the bass right, nothing ever comes together very well. rives 2004-08-25T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/introduction-to-acoustics Throughout this series we hope to educate and illustrate some of the fundamental points of room acoustics. This is by no means meant to be an intensive course on acoustics, which by the way, for those that are interested, we recommend and have a list of educational and training opportunities on our website. However, this will give the reader some fundamentals and resources that may help in solving their own acoustical needs and problems. In this introductory article we would like to accomplish a few goals: First will be to discuss many of the facts and myths that exist regarding acoustics. The second will be to give a very brief definition and description of some of the acoustical terms you may have heard. Lastly, we will discuss our direction in this series of articles. rives 2004-08-25T00:00:00+00:00 Tech Article http://www.audioholics.com/education/acoustics-principles/acoustical-measurements-what-are-they I have heard some people claim "I just listen and walk around the room and clap my hands and I know what to do." I would say this is another "myth". What is true, is that final tuning of a room often does require extensive and subjective listening. rives 2004-08-25T00:00:00+00:00 Tech Article