Crossover Design for Speakers

Crossover Design for Speakers Crossover Design In terms of crossover design, there are two distinct options; passive or active crossovers. Passive crossovers are the most common implementation, since only one amplifier is required. In this case, filters comprising passive components (inductors, capacitors and resistors) are used to ensure that the correct frequency range is supplied to each driver. Low-pass, high-pass and band-pass filters are commonly used and need to be matched to ensure that the frequency roll-offs compliment each other, such that in the crossover zone(s) the combined acoustic output of the drivers maintains a flat frequency response. In terms of these passive filters, it is the order of the filters used that is the primary consideration. A first order filter has a roll-off of -6dB per Octave and a Butterworth characteristic. First order filters are undesirable for two reasons; a +3dB peak is introduced at the centre of the crossover band and the crossover bandwidth is large due to the gentle roll-off, which means the drivers need to be capable of handling a greater frequency range. However, first order filters require the least components, incur less power loss as a result and do not introduce a phase change in the output. Second order filters are the most commonly used type in passive crossovers, since they are relatively simple but solve the problems associated with first order filters. The roll-off is -12dB per octave and the filters may be designed with a Linkwitz-Riley characteristic which maintains a flat frequency response across the crossover band, unlike the combination of Butterworth filters. Third order filters offer a roll-off of -18dB per octave, however there is a problem of phase separation; in a two-way configuration there is a phase shift of 270 degrees which â€Å"can result in lobing and tilting of the coverage pattern† (DellaSala, G. 2004). Some designs such as the D’Appolito configuration[1], which uses three drivers, actually make use of this phase separation in order to minimise lobing, however the D’Appolito configuration is notoriously complex and difficult to implement well without precise driver measurements. If a high-order crossover is desired, fourth order filters are perhaps the best choice. Although they are more complex in terms of design and require more components, the advantages are a small crossover bandwidth (roll-off is -24dB per octave) and a 360 degree phase shift; hence no phase correction is required. Passive crossovers beyond fourth order are generally not considered. Borwick (2001, p.267) notes these â€Å"are seldom used in passive crossover designs because of their complexity, cost and insertion losses†. The other approach to crossover design is the active crossover. In this case active filters (normally based around op-amps) are used to divide the input signal into the required frequency bands prior to amplification; the crossover has multiple outputs and a separate power amplifier is needed for each frequency band. Some audiophiles complain that active crossovers (which normally employ high-order active filters) are not a good choice, due to the poor transient response of high order filters. However as Elliot (2004) notes, â€Å"the additional control that the amp has over the drivers behaviour improves the transient performance, and especially so at (or near) the crossover frequency the most critical frequency point(s) in the design of any loudspeaker†. Apart from the increased complexity and multiple power amplifier requirement, active crossovers are far superior to their passive counterparts in almost every way, although some purists may disagree. Good quality op-amps are cheap, as are the required resistors and capacitors (since these do not need to handle much power). The active solution means frequency response is no longer defined by the quite complicated combined resistive, capacitive and inductive load of the passive crossover and drivers. Thus the frequency response of the crossover is independent of dynamic changes in the load. Furthermore, the active crossover makes it easy to tune the crossover dynamically; with most commercially available active crossovers one can simply dial in the required frequency bands. Efficiency is improved with active crossovers, since no power is lost by the amplifier in driving passive inductors or resistors. The amplifier also has the best possible control over transient response, since there is nothing between it and the driver other than cable. Thus the amplifier can respond directly and â€Å"presents the maximum damping factor at all times, regardless of frequency† (Elliot R. 2004). In view of the above one may then wonder why passive crossovers continue to remain so popular, since it seems far more logical to implement frequency division before amplifying the signal. Ease of installation is perhaps the main factor. Almost all commonly available hi-fi systems use speakers with passive crossovers. For the consumer this makes things easy; the speakers are simply connected to the amplifier and installation is complete. In contrast, turnkey active solutions for the average consumer are not forthcoming, although rack-mounted â€Å"professional† active crossovers can be obtained for quite reasonable prices (around  £150 for a 4th order 2 way Linkwitz-Riley design)[2]. However, these require a fair amount of audio engineering expertise to set up correctly and the typical home listener simply does not possess this knowledge. For the high-budget client seeking the best audio reproduction, active crossovers are certainly the best option; the technical advantages have been seen to be numerous. This is offset by the fact that the system will be far more complicated to correctly install, but it is assumed in this case that complexity of installation is of little concern to the high-budget client who is unlikely to handle the installation themselves in any case. For the low-budget client, the best solution is the passive crossover. It is a simple option, only requires one amplifier and yet produces acceptable sound quality. It is far from the best solution, but adequate if a competitive price point is desired. In conclusion, all but a few dyed-in-the-wool purists will agree that the active crossover is a superior solution in terms of quality and control. What it lacks in simplicity is outweighed by a far superior level of control over frequency response and the drivers themselves. However, due to issues of complexity one can expect that the traditional passive crossover shall continue to lead a healthy existence in the majority of loudspeaker designs. Sources Borwick, John. (2001). Loudspeaker and Headphone Handbook, Focal Press. DellaSala, G. (2004). Filter Crossover Types for Loudspeakers, Audioholics Magazine. Dickason, V. (1995). The Loudspeaker Design Cookbook, Audio Amateur Publications. Elliot R. (2004). Active vs Passive Crossovers, Elliot Sound Products. Rossing, T. (1990). The Science of Sound, Addison-Wesley. 1 [1] D’Appolito’s full 1983 paper may be obtained here: http://www.aes.org/e-lib/browse.cfm?elib=11762 [2] For example the Samson S-2: http://www.inta-audio.com/products.asp?partno=sto-oth-sam2w

Ethical Consumerism

Ethical Consumerism What is ethical consumerism? Ethical consumerism is the purchasing of products and services produced in a way that minimizes social and environmental damage while avoiding products and services having a negative impact on society or the environment (http://www. scribd. com/doc/19589310/Contract-Law). Ethically made products are those that are produced with the least harm to the environment, animals, and humans. There are four types of ethical buying. The first one is positive buying as in energy saving light bulbs.The second is negative purchasing which is avoiding products that disapprove of, such as battery eggs or gas-guzzling cars. The third one is company-based purchasing. You choose whether or not you support a company based on what it produces. The last one is the fully-screened approach. The fully-screened approach is a combination of the first three. When purchasing products or services the consumer should consider the quality of the product, the conditio ns in which the products produced and if any harm is caused to the environment.When items are sold at really low prices, it should make the consumer stop and think, â€Å"Is this really a bargain? † How consumers spend money influences social and economic justice, the environment, animal welfare, and democratic freedoms. As consumers, we have an ethical obligation to society. As consumers, we should only buy products that are safe to use or healthy to consume, In order to do that, we must not buy from companies that exploit humans or animals maintain and increase social poverty, inequality and deprivation (http://www. atheistnexus. org/group/consumerethics).We must identify companies that value their employees and customers, pay fair wages, and provide a safe and healthy work environment, and maintain sustainable business and environmental practices and practice positive buying. Positive buying is favoring ethical products, and businesses that operate on principles based prim arily on benefit for the greater good rather than self-interest,allowing for business self-interest only for the perpetuation of doing general good outside of self (http://knowmore. org). Moral boycotting is another way to help society.Moral boycotting is the practice of avoiding or boycotting products which a consumer believes to be associated with unethical behavior. Reasons for boycotting would be factory farming, harm to the environment, unsafe and unhealthy working conditions, and low wages. Boycotting can damage reputations and cause a loss in profits. If we are a socially responsible organization, you would think people would prefer to buy from us than a company who isn’t socially ethical. As consumers, we have the power and must take responsibility for this power by making informed and empowered choices in the products we purchase (http://www. mallsimplelife. com/2009/09/dont-sweat-the-big-stuff/). We must be positive consumers, and use our buying power to influence t he effects consumerism has on the living planet. References (Ethics and Consumer video [Video file]. (n. d. ). Retrieved from http://library. uco. edu ) (http://www. scribd. com/doc/19589310/Contract-Law) (http://www. atheistnexus. org/group/consumerethics) Small Simple Life : Positive Impact with Ethical Consumer †¦ (n. d. ). Retrieved from http://www. smallsimplelife. com/2009/09/dont-sweat-the-big-stuff/

Can Money Buy Happiness - 891 Words

â€Å"Can money buy happiness?† has been a cliche question for centuries, and there have been numerous studies and debates on this topic. Yet, no one seems to have a definite answer. In the video Money and Happiness, Michael Norton states explicitly that money does bring people happiness if you spent it on other people rather than on yourself. Although his interesting and novel answer is contrary to people’s natural instinct, it makes me reflect on my past experience of spending on others, and helps me understand the true benefits of this spending habit. It is common that most people are more than willing to spend money on themselves, either to fulfill their requirements or to satisfy their vanity, and I was one of those people. Being the youngest child of the family, I was spoiled. My families, especially my grandfather, have always bought me whatever I desired without blink of an eye. As a result, I took his affection for granted and often spent money in a self-centered way. There were numerous times when I spent on clothings and accessories to simply please myself. It was not until my grandfather’s birthday a few years ago that I realized it is not about spending, but the fact of spending on others that promotes true happiness. On that day, I went to the mall and bought a few shirts with a birthday card. Those gifts were not costly so I did not expect much reaction from my grandfather. But instead, the moment I handed my gift and said â€Å"Happy Birthday† to my grandfather, IShow MoreRelatedCan Money Buy Happiness?1324 Words   |  6 PagesCan money buy happiness? It’s a philosophical question that has been discussed for centuries and there is no simple answer. For example, Graham Hill in â€Å"Living with Less. A Lot Less† gives his input on this highly debated topic through a multitude of short anecdotes. She asked herself not if â€Å"Money can buy happiness,† but if money could â€Å"help buy happiness† (Rubin 293). She also brings up the idea of modest splurging and spending out as methods of using money to help one buy happiness. Rubin describesRead MoreCan Money Buy Happiness?1637 Words   |  7 Pages Does Happiness Come With A Price? Malcom Williams Can Money Buy Happiness? Abstract In this paper, I argue and show various sources addressing the correlations between money and happiness through subjects such as pro-social spending, materialism, the pursuit of spending on others, and the effects of homelessness on physical and mental health. Much of the time, cash can have a negative impact on both, particularly the. Now and again, in any case, cash may positively affect satisfactionRead MoreCan Money Buy Happiness?1110 Words   |  5 PagesCan Money buy Happiness? Money is people’s number one priority. It enables them to purchase food, clothing, and shelter. Money can buy anything with a price on it, but can it buy happiness? Happiness is not an item you can buy, it is something you can feel. Money cannot bring you happiness, only satisfaction. We learn growing up not everything in this world is free. Money can only give you a short term of happiness. When you buy everything you want, you do not have anything to look forwardRead MoreMoney Can Buy Happiness1523 Words   |  7 PagesHappiness is a mental state of well-being characterized by positive emotions ranging from contentment to intense joy†. Notice that happiness is within the range of contentment to intense joy. Every single thing in the world which brings contentment or joy costs money and therefore, it is money which brings happiness. Nothing can be yours without money being spent either by the person experiencing this happiness, or by others spending money so that they can be happy. 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Faustus Essay - 2501 Words

â€Å"Out of ancient myth of the magician who sells his soul to the Devil for occult powers, Marlowe has fashioned a veritable fable of Renaissance man† (Source 5 113). nbsp;nbsp;nbsp;nbsp;nbsp;The goal of any true renaissance man is to improve himself. This goal may border on heresy, as it leads to a man trying to occupy the same position as God. Lucifer commits this same basic sin to cause his own fall. To Doctor Faustus, this idea of sin is of no concern at the beginning of Christopher Marlowe’s Doctor Faustus. Faustus’ goal is to become god-like himself. In order to accomplish this, he learns of science and shows an interest in magic. He turns to the pleasures of magic and art and the poewr of scientific knowledge as substitutes for†¦show more content†¦That’s hard. /†¦/If we say that we have no sin / We decieve ourselves, and there’s no truth in us. / Why then belike / We must sin and so consequently die, Ay, we must die an everlasting death/†¦/†¦Divinity, adieu!† (Marlowe 15). Having denied God completely leaves Faustus completely desolated from society, In acceptance of Mephistophilis, Faustus completely denies society and all that has been handed to him by science and learning. â€Å"Marlowe shows that one who rejects his intellectual, social, and spiritual inheritance experiences pain of personal isolation, anxiety, dread, and meaninglessness† (source 5 150). Finally, Faustus turns to magic as his method to improve himself infinitely. nbsp;nbsp;nbsp;nbsp;nbsp;Faustus’ decision to become a magician marks the fatal culmination of his attempt to improve himself infinitely. At this point, Faustus notes, â€Å" A sound magician is a mighty god / Here, Faustus, try thy brains to gain a deity â€Å" (Marlowe 15). This marks the crossover from attempting to improve himself as a mortal and attempting to become immortal. He believes that magic is his only feasable option to become immortal. â€Å"He dismisses divinity because it seems to invite a hateful determinism which denies the real freedom to ‘settle’, ‘begin’, and ‘ be’†(source 10 158). Faustus’ deal with Lucfier ultimately commits Faustus to this belief. By making a deal withShow MoreRelated Dr. Faustus Essay: Faustus Changing Relationship with the Audience1521 Words   |  7 PagesDoctor Faustus Changing Relationship with the Audience Any good drama will have interesting and multi-faceted characters; some go a step further by developing some of those characters throughout the story, using the events of the plot to change them in various ways. The audience (in the case of a play) follows the characters throughout, watching as they move away from their originally crafted personalities and become something different. Naturally, during this period, the audiences opinionRead More Dr. Faustus Essay - Pride, Insolence and the Fall of Doctor Faustus1949 Words   |  8 PagesPride, Insolence and the Fall of Doctor Faustus  Ã‚   As a highly revered individual - a doctor of theology who is also involved in liberal arts, medicine and law - Doctor Faustus possesses limitless knowledge. Nonetheless, unfortunately the more people know the more curious, thirsty and greedy for knowledge they become. Thus, wanting to know more and therefore, gain supernatural power, Faustus creates his own fall through pride, insolence and child-like behavior - the by-products of the dominatingRead More Christopher Marlowes Dr. Faustus - The Folly of Dr. Faustus623 Words   |  3 PagesChristopher Marlowes Dr. Faustus - The Folly of Dr. Faustus Christopher Marlowes tragedy of Dr. Faustus envelops a realm of theological issues around one mans quest for knowledge. Feeling a university education to be inadequate for his purposes, Faustus makes the ultimate sacrifice possible to quench his thirst for otherworldly wisdom. Yet even though he gains amazing powers and a broad reputation as a man in the know, his quest is incomplete. He actually learns very little. The natureRead MoreCharacter Description: Dr. Faustus801 Words   |  4 PagesFaustus - The protagonist. Faustus is a brilliant sixteenth-century scholar from Wittenberg, Germany, whose ambition for knowledge, wealth, and worldly might makes him willing to pay the ultimate price—his soul—to Lucifer in exchange for supernatural powers. Faustus’s initial tragic grandeur is diminished by the fact that he never seems completely sure of the decision to forfeit his soul and constantly wavers about whether or not to repent. His ambition is admirable and initially awesome, yet heRead More Dr. Faustus Essay: The Role of Helen of Troy1163 Words   |  5 Pagesof Troy in Doctor Faustus  Ã‚  Ã‚   To adequately describe the role that Helen plays in Doctor Faustus, it is necessary not only to look at the scene in which she features, but also all the instances that Faustus takes some form of pleasure from physical and sensual things. We need to do this because this is what Helen is symbolic of; she represents the attractive nature of evil in addition to the depths of depravity that Faustus has fallen to. It is fair to say that Faustus represents the quintessentialRead MoreShakespeare s Twelfth Night, And Marlowe s The Tragical History Of Doctor Faustus1585 Words   |  7 PagesEveryman, The Second Shepherds’ Play, Shakespeare’s Twelfth Night, and Marlowe’s The Tragical History of Doctor Faustus. These plays reflect many of their times’ heated topics and concerns. While the endings to each of these plays significantly contrast, the themes within each play fully prepare audiences for the ending to which will be further explained. Of these plays, Everyman and Doctor Faustus are perhaps the most similar, yet the most contrasting. While both appear to explore the subject of deathRead MoreFaustus, By Dr. Faustus2669 Words   |  11 Pagesoutset, Dr. Faustus is in his study contemplating what academic discipline is the most fulfilling. He reviews a number of disciplines in his mind, such as logic and medicine (which he believes he is already adequately distinguished in), and law and theology (which he believes to have inherent inadequacies). Dr. Faustus’s route from religion to magic seems to be forcedly cobbled together in order to elicit a certain emotion towards sophists as a whole, and Marlowe laboriously thrusts Dr. Faustus into becomingRead MoreDoctor Faustus : The Relationship Of Mephastophilis And Faustus1597 Words   |  7 PagesDoctor Faustus: The Relationship of Mephastophilis and Faustus In Christopher Marlowe’s Doctor Faustus, the tragic protagonist Faustus finds himself tired of his previous pursuits in logic, medicine, law and religion. He falls upon the decision to explore a new and taboo area of knowledge: the black arts. Once he settles on this idea, he begins a relentless endeavor to quench his thirst for higher knowledge, wealth and success through learning supernatural powers. Alas, his admirable ambition andRead MoreDoctor Faustus978 Words   |  4 PagesPoor Faustus believes it is he who has called upon the demon Mephistopheles and it is his tongue that orders the servant of hell, yet he could not be any more mistaken. In reality, Faustus is the one with strings attached to him and it is Lucifer, Mephistopheles, and the Evil Angel playing the role of the puppeteer. Nevertheless, Faustus remains a student to the ideology of Christianity throughout his adventures, even amongst the bleakest of hours. God never leaves the side of John Faustus, as HeRe ad MoreFaustus Tragedy2251 Words   |  10 PagesDiscuss Dr. Faustus as a tragedy Dr. Faustus is a tragedy because the main character falls as a victim of his own circumstances, and is a victim of himself. He is a man with all the potential and possibilities to be successful. He is a Renaissance man who is versed in every aspect of science, philosophy, the arts, education, and genius, yet, he utilizes his energy and wit into absolutely nonsense and unnecessary goals, such as his obsession to be a magician, and his ridiculous fixation for power: