In th is p ap er a sh o rt su m m ary is given o f th e criteria in vo lved in lin e array d esign th eo ry. A set of mathematical expressions to analyze the performance of loudspeaker line arrays is provided. For line arrays, this means reducing the gain at the top and bottom of the array. A line array is a line of adjacent loudspeakers that coherently couple together creating a line source. Through this model, multiple images more than 2 can be matched simultaneously and. All i need, is a basic plans to start experimenting. A line array is a loudspeaker system that is made up of a number of usually identical. A 6 db level difference between two locations is not a theory it is true or not true. Pipeline transmission line line array a conventional dynamic loudspeaker has a more or less spherical radiation pattern. Eaw technical brief kf760 technology overview free. Build a mini line array along with all my other interests in life, audio and speaker building is near the top.
The only region that is lobe free at all frequencies lies along a line running directly out from center stage. Line arrays of loudspeakers are often employed to provide increased directivity, generally in the vertical plane. Replied by tarkus57 on topic find line array plans you are right, but the problem of hardware, and electronics i have it solved. Even with voice and sound recordings one often seeks a condition free from sound reflections similar to a free field, even when during postprocessing specifically desired spatial impression will be added, because this is not distorted by any sound reflections of the recording room. This concept uses a number of loudspeakers aligned in a vertical array to provide an in phase feed creating a near line source to the listeners. Quite a complex subject yet we have tried to give you a comprehensible access. Rather, modeling with a useful degree of accuracy requires a computational code that uses a highresolution measurement of the complex directionality of actual loudspeakers, such as mapp online. This is instead of the spherical wavefront emitted from a point source.
For example, you can concatenate the handles of the figure, axes, and line objects into one array, harray. The extensional theory relates equations between arrays and equations between their elements. Line array performance at mid and high frequencies martin audio. A new multiple images matching theory model is proposed in this paper to generate dsm from aerial three line array digital images. It is widely recognized that tall columns of speake rs that comprise a line array have significant benefits when properly implemented. Pure line array theory is based on pure geometry and the thought experiment of the free field where sound is free to propagate free of environmental factors such as. Pure line array theory is based on pure geometry and the thought experiment of the free. Design guidelines for practical near field line arrays james r. The source transmitted tones in the frequency band of 30160hz at levels comparable to those of a merchant ship, with resulting signaltonoise ratios of 915db. We should probably turn back the clock a little before we go on. This paper applies geoacoustic inversion to acousticfield data collected on a bottommoored horizontal line array due to a continuouswave towed source at a shallow water site in the barents sea.
These cabinets are close enough together so there is minimal interference and can provides an evenly distributed sound output pattern. However, graphics arrays can contain more than one type of graphics object. If a number of identical drivers are placed in a vertical line, then you get a totally different radiation pattern. Schelkunoff, a mathematical theory of linear arrays, bell system. Starting from the very basic type of line arrays, different configurations of arc and.
Pdf simulation and implementation of sound focusing using. Advanced line array design with laps ii electrovoice. Community oriented diy loudspeaker design plans, general resources downloads, chat and forum. The line array is far too big a thing to set up in the same way, and once its set up you dont really want to have to move it, so you need to be sure that the positioning is right, the height is right, the horizontal angling is right, and most of all it that the array takes up the optimum jshaped curve to distribute sound evenly to the front and back of the audience, and everyone in between. Ie the dimensions of a box, for two speakers 8 or 10, and a driver with a waveguide a 1 or 2. Amajor drawback to a line source in practice, a line of sources is that its acoustical behavior is highly frequency dependent for a given line length. The directive point source model has been used to simulate line arrays to study. At first a set of expressions for straightline arrays is developed, including the directivity function, polar response, quarterpower angle, onaxis and offaxis pressure re. This computation shows that it is theoretically possible to construct an audio line array that follows the theory at low frequencies. Ureda jbl professional northridge, ca usa abstract line arrays of loudspeakers are often employed to provide increased directivity, generally in the vertical plane. Design guidelines for practical near field line arrays.
L2 problem geometry our goal is to compute the acoustic. In this course you will be expected to learn several things about vector spaces of course. All books are in clear copy here, and all files are secure so dont worry about it. Beyma line array project page this model is the result of an extensive and intense research of every single constituent part of an electrodynamic loudspeaker, rethinking the basics and taking care of every detail, to withstand the extreme power conditions it has been designed to work in. A true line source will create a cylindrical wavefront propagating perpendicularly to the line source. This course is aimed at more experienced sound engineers and systems engineers wanting to expand their knowledge of highend audio system design. However, the array requires more than 1,000 fifteeninch drivers, spaced twenty inches centertocenter, to do it. Feel free to continue to look at different results on. Therefore, to provide consistent performance with frequency, techniques must be used to offset the behaviors. The vast majority of concert public address pa systems used nowadays consist of hanging line arrays, which help reduce acous tic shadows and increase the distance of the line source effect 1. There are several very practical reasons why line arrays have replaced horizontal arrays for many portable. In a nutshell, a line array is a column of speaker cabinets designed to collectively function like one large speaker. The first set of speakers i ever built had drivers that came from radio shack in 1978.
For improved performance, contemporary line arrays employ specially designed loudspeaker elements to provide a nearly continuous line. Physical theory tells us that the severity of aperture effect can be reduced by gradually reducing the amplitude of the wave to zero near the edges of the aperture. A line array is a loudspeaker system that is made up of a number of loudspeaker. Then draw a vertical line up from this point and determine the value of f at this point. But why are line arrays the current best practice in largescale pa, how did they evolve, and. Pdf in this paper the study and experiments into loudspeaker arrays for the purpose of. Box line array 10 in mid hi suara joss tidak mengecewakan duration. The gsl8 houses two 14 neodymium forward facing lf drivers and two side firing 10 neodymium lf drivers. The role of these speakers will be to serve as reference monitors in both my home studio. Flex array combines elements of line array theory and virtual point source theory in one. Acoustic linearity architecture paired with cst allows the use of multiple different alclass elements together in an array without sacrificing the elemental linearray theory basics, resulting in a coherent and symmetrical line source from the largest cabinet at the top of the array. Jan 8, 2014 yeah we all know the theory very well and you dont have to remind us. Line array theory is based on pure geometry and the thought experiment of the free field where sound is free to propagate free of environmental factors such as room reflections or temperature refraction. At first a set of expressions for straight line arrays is developed, including the directivity function, polar response, quarterpower angle, onaxis and offaxis pressure re sponses, and twodimensional pressure field.
The paper is focusing on the direct sound frequency response of line arrays. Flex array flex array user manual page 7 flex array concepts the flex array system is a modular flexible array loudspeaker system designed to deliver extremely high fidelity audio in a range of medium scale fixed and portable sound reinforcement applications. Given a fixed line length, classic line array theory and reality diverge very. For improved performance, contemporary line arrays employ specially designed loudspeaker elements to provide a nearly continuous line source. If you understand the theory behind the directional characteristics of sound sources. Although character arrays have the advantage of being able to query their length, they themselves are too primitive and dont support a range of common string operations. Matchedfield geoacoustic inversion with a horizontal. For example, copying a string, searching for specific pattern etc.
Tow speed was 4 knots characterisation of a digital thin line towed array experimental assessment of. The murphy corner linearray mcla is a new type of line array loudspeaker system that i have designed to meet my own requirements for reference monitor loudspeakers with sufficient output to also serve as the sound reinforcement system for my band. This paper will examine the underlying theory and assumptions behind line arrays and will present danley. To solve the integral gives the most commonly used expression for directivity of a line array. These arrays can provide a long throw effect as well as.
Horizontal patterns of leftright stacked and flown subs. A line source is a hypothetical onedimensional source of sound, as opposed to the dimensionless point source. Directional behavior of an eightmeter long array of sixteen omnidirectional sources. The basic problem of every sound reinforcement system for large venues is the fact that. For a given angle, determine the point of intersection of a radial line from the origin with the perimeter of the circle. Contours the vertical sound dispersion such that floor and ceiling reflections. An extensional theory of arrays has been studied formally, most recently in 7 and 1. That said, practical line array systems remain very useful tools, regardless of whether the continuous line array equation applies. Here is what i cannot tell you by either of the above methods. The gsl12 is a line array module specifically designed for largescale sound reinforcement. In the free field, sound which has its origin at a point a point source will be.
1161 806 1596 1105 1418 1224 245 1417 25 461 499 258 376 349 643 706 47 562 1429 1575 1387 911 727 923 30 375 1133 742 1382 50 1468 457 360