ArraySHOW - Instruction Manual

7/21/2019 ArraySHOW - Instruction Manual

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ArraySHOWTM

Instruction Manual

Table of Contents

InstallationWhat's new in version 1.1

General usage commentsConstructing arraysSaving your workWorking with multiple array documentsPrintingCopy and paste into other programsPreference Settings

Theoretical Background and Interpretation of ResultsBandwidth of ResultsThe Directivity GlobeSignal Delay, Misalignment, and Steering

ArraySHOW and Arraying GuidelinesMinimizing Device Interference for Smooth CoverageDegree of array solution possibleProperties of the Individual Array ElementsSpecific Guidelines to Narrow the "Angular Zone of Interference"Using Device Interference Constructively

Additional CommentsArraySHOW Seminar Video TapeHistorical Comment"Perfectly Arrayable Boxes"

Appendix I: Table of Device Physical Dimensions

Installation

From CD-ROM:

Insert the CD into the CD-ROM drive. If the program does not start automatically,double click the file named "setup.exe"

From a downloaded installer:
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Show/Doc/ArraySHOW%20Help.html%23Perfectly_Arrayable_Boxeshttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Appendix_I:_Table_of_Device_Physicalhttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Appendix_I:_Table_of_Device_Physicalhttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Appendix_I:_Table_of_Device_Physicalhttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Perfectly_Arrayable_Boxeshttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Historical_Commenthttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23ArraySHOW_Seminar_Video_Tapehttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Additional_Commentshttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Using_Device_Interference_Constructivelyhttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Specific_Guidelines_to_Narrow_thehttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Properties_of_the_Individual_Arrayhttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Degree_of_Array_Solution_Possiblehttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Minimizing_Device_Interference_forhttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23ArraySHOWTM_and_Loudspeaker_Arrayinghttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Signal_Delay_Misalignment_andhttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Directivity_Globe_View_Interprestation_http://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Bandwidth_of_Resultshttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Theoretical_Background_and_http://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Preference_Settingshttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Copy_and_Paste_into_other_programshttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Printinghttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Working_with_Multiple_Documents_forhttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Saving_your_workhttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Constructing_new_Arrayshttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23General_Usage_Commentshttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Whats_new_in_version_1.1http://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23installation


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If installing from the web, download and run the "setup.exe" file.

What's new in version 1.1

Fixed a bug in the globe drawing code that caused an overflow error onWindows 2000 and Windows XP

A few inner-loop optimizations to eliminate some duplicated trig and exponentoperations

Removed "convolve" button and made convolution calculation automatic witheach change to an array

Included device data installation to main program installer Added all devices currently available on the EVI website as separate WinZip

archives to the main installer Updated on-line documentation (this document), adding explanatory figures

and converted to more-standard HTML format. Added access to on-line documentation from Help Menu.

General Usage Comments

The use of ArraySHOW is both highly intuitive and powerful. It allows the user toanalyze arrays of loudspeakers independent of the room, to look directly at the lobes

and nulls of given array geometries. ArraySHOW asks/allows the user to:

1. Build and array by selecting, locating, and aiming one or moreloudspeakers. A diagram of the array built will appear for the you when youclick ok.

2. Select a frequency and microphone distance. Results are updatedinteractively as the parameters and/or array is modified. Directivity isdisplayed in both horizontal and vertical polars. A unique and highlycolorful"directivity globe" which ranges from the highest output level in red to

the lowest output level in blue.3. Quickly and easily edit the array to convolve new results to optimize array

directivity.4. Save arrays for recall at any time, and quickly compare different

results. (See details on comparisons, below.)

Constructing new Arrays
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1. Move the cursor to the spread-sheet

box:2. Double-click to add or edit devices. (Click once and press the "del" key to

delete a device)3. When you double-click, the "Add Device to Array" box appears:

a. Select a device by clicking on the "Device" select arrow. This will

provide a list of database items included in your copy of ArraySHOW.(Additional devices may be added to your installation by copying theappropriate *.spd files into the "devices" folder in the ArraySHOWinstallation directory.)

b. Scroll the device you wish to select and click on that device.c. If the device is not listed in the list, you may select an individual *.spd

file anywhere in your file system by selecting "Browse"

d.

Click on X,Y and Z in turn to indicate the coordinate position of thedevice in the array. (in inches or centimeters -see the preference section).This position represents the center of the front face of the device.

e. Set azimuth and elevation of the device selected (enter in degrees) andclick to enter.

f. Set delay and relative gain of each device as desired.g. Click "OK" when you are finished editing this device.
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4. Repeat step 3 as required to complete your array.Note: in real life it is not possible to place multiple devices in the same physicalspace. When building arrays, you must take into account the physical dimensions ofeach device. For example, ArraySHOW will allow the acoustic centers of two X-

Array Xf enclosures to be separated by one inch, yet physical placement of thiscombination is not possible. See Appendix I for dimensional dataassociated with devicesincluded in your database.

Construction of the array can be verified by viewing the display in the lowerleft hand corner showing the coordinate system and the orientation of eachdevice.

5. When array construction is completed, choose the one-third-octave centerfrequency you wish to view by using the "Frequency" selector. Note that you

can quickly step up and down through the frequency range with the up anddown arrow keys when the frequency selector is

highlighted.6. Select the distance from with the array is to be viewed using the "distance to

Microphone" slider.

7. Results are displayed interactively as you manipulate the array, distance, andfrequency controls. See "interpretation of results", below.Saving your work

Arrays may be saved by choosing the "Save" or "Save As" commands.

Working with Multiple Documents for Comparison

Multiple "open" array documents may be compared by selecting the "next window"command from the program icon (immediately to the left of the File Menu).
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The CTRL-F6 keystroke can also be used to quickly cycle through all open windowsin ArraySHOW. Alternatively, you may move between open Windows using the"Window" menu.

Printing

The entire screen may be printed in gray scale or color. Also, individual arraydiagrams, polar plots, and directivity globes may be selected and printed in gray scaleor color.

Copy and Paste into other programs

The entire screen or individual array diagrams, polar plots or directivity globes maybe selected and then cut and pasted into Windows-compatible programs that handlegraphics.

On Windows 2000, XP, or later, you can use CTRL-PrintScreen to capture the entirescreen.

To capture individual array orientations, polar plots, or globe plots, click on the viewof interest and choose "Copy to Clipboard" from the "Edit" menu. (You can changethe copied image size and color scheme inside the Edit->Preferences dialog.)

Preference Settings

Choose Edit->Preferences, and you will various settings, including:


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Choice between color and gray-scale globe displays The size in pixels of copied globes, polars, and vector diagrams Choice between English (IP) and Metric (SI) units Optional display of dB legend on globe diagrams

Theoretical Background and Interpretation of Results

ArraySHOW predicts the interference or interaction of multiple devices as a functionof device type, location and aiming with a high degree of accuracy. Basically, this isdone by mathematically convolving measured device amplitude-only sphericaldirectivity data with the complex (amplitude and time) calculated directivity of pointsources located at the center of each device. (Horn mouth for component horns and

box front for systems.) This process is described in detail in Mark Ureda's AudioEngineering Society Preprints available from EVI Audio:

The Convolution Method for Horn Array Directivity Prediction (Preprint 3790) Directivity Response of Horn Arrays (Preprint 3963) Amplitude and Signal Delay Shading of Vertical Horn Arrays (Preprint 4061) Wave Field Synthesis with Horn Arrays (Preprint 4144)

Extensive validation of ArraySHOW performance has been undertaken; the results are

shown in the preprints.

Bandwidth of Results

At each available center frequency, the results are show for a spectrum one-thirdoctave wide.

Directivity Globe View Interpretation

The globe view is a three-dimensional representation of the array's response at thefrequency and distance specified in the controls above. The globe is drawn as if youare standing at the end of the "+X" axis looking toward the origin.


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Single HP640 oriented toward +X axis Polars of same HP640. No

High SPL levels are shown in red, and the lowest are shown in dark blue.

Signal Delay, "Misalignment", and "Steering"

The option of adding signal delay to selected components or systems should not beconfused with the signal delay used in electronic processors associated withbiamplified or triamplified multiway loudspeaker systems. The latter are used tomatch arrival times of components within the single multiway system. Adding signaldelay to a multiway system in ArraySHOW affects the entire system.

For both systems and components, added signal delay can be used for device"misalignment." This technique is useful because part of the pattern is substantially

improved from a "smoothness" standpoint while a corresponding part of the polarradiation is mare "worse". Oftentimes, the technique can substantially improveradiation smoothnes onto an audience space while "making worse" the radiation intothe corresponding upper half or ceiling portion of the array. Since there is noaudience present in the ceiling, the net effect from an observer's point is animprovement because of the misalignment, in terms of smoothness and evenness ofcoverage (seeMinimizing Device Interference for Smooth Coveragefor details).

ArraySHOWTM

and Loudspeaker Arraying Guidelines

Loudspeaker components and systems are typically "arrayed" -- used in multiples -- inorder to achieve more uniform audience coverage and/or higher sound pressure levelsthan are possible with a single device. In general, we believe that the destructuveinterference effects of multiple loudspeakers in arraysis a subject too little understoodin our industry. Furthermore, there are a number of beliefs about "arrayability" and
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the propotion thereof which seem to fly in the face of both the laws of physics andactual demonstration.

EVI Audio has developed and offered ArraySHOW software to the industry to aid thesystem designer -- whether for fixed installation or concert touring -- in maximizing

the performance of arrays. ArraySHOWshows quickly and easilythe interaction ofmultiple speakers as a function of frequency, individual device characteristics and therelative location and aiming of the devices. Thus, optimizing the array isan iterativerather than automaticprocess. the following material is intended tosimplify this iterative process for common applications.

The interaction of multiple loudspeakers can also be used constructively, e.g. avertical dipole array that extends vertical directivity control to a frequency lower thanthe size of the horn operating above it in frequency allows. This application iscovered as well.

Here are three major points on the destructive interference effects of multipleloudspeakers in arrays:

Optimal arraying is not manufacturer or model-number specific. Boxes that fit into nice physical arrays do not necessarily array

acoustically in an optimum (read "uniform coverage") way. In fact, thetypical box is likely to array poorly, and only a few take into account on ormore of the principles outlined below which minimize (but do not eliminate)array coverage problems.

The idea that tight-packed trapezoidal boxes form a "coherent wavefront"across the bandwidth, with a "virtual acoustic source" at the intersectionof the individual box axes extended to the rear of an array, is incorrect. Inall cases, one is dealing with multiple acoustic sources, each somewhere withineach box. No audio marketer or engineer can change this.

To get the basic idea, imagine two identical and equally-powered trapezoidalenclosures viewed from the top and tight packed the way one sees it much of the time:


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Box draft angles are usually on the order of 15 or less (Higher draft angles sacrifice alot a box volume, which is not good for bass), while the nominal horizontal coveragefor each system is say, 60. Ignoring the important issue of just over what frequencyrange the typically smallish box can maintain the nominal 60 coverage angle, thismeans that box axes are displaced by only 30,for 30 of pure overlap from the two

systems.

What does overlap do under the conditions noted above? Whenever two transducersoperate in the same frequency range and cover the same audience area at levels equal

to one another, unless the observer is on the exact centerline of the array, he or shewill receive two strong signals from two different sources at two different distances.There will be strong cancellation of output at those frequencies where the distancedifferences are equal to one-have wavelength or multiples thereof. This efffect iscommonly called "comb filter interference."

For typical box dimensions, these cancellations are right in the middle of the criticalvocal range (500-1000 Hz). As the observer moves to the left and/or right of the arrayaxis, very audible (to many people) disturbing changes in sound quality will beobserved as the specific cancellation or null frequencies "swish" back and forth along

the range. In extreme cases, unacceptable reductions in voice intelligibility, spectralfidelity, and/or gain-before-feedback occur (usually in the vertical case, of whichfigure 1 is not).

Think of this "interference zone" as an angular zone in the listening space, locatedsymmetrically about the array axis. This phenomenon is very general for more thantwo array elements in both horizontal and vertical planes, difference specific models


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in an array and varying amplitude levels -- the typical "real world" situation. Thedetail and geometry of what has been described is different, but the general effect isthe same.

Minimizing Device Interference for Smooth Coverage

Degree of "Array Solution" Possible

The destructive interference of loudspeakers in arrays can be reduced, evenminimized, but not eliminated.

Properties of the Individual Array Elements

The lower the frequency to which a device maintains its nominal coverage angle, theless severe are the arraying effects.

The coverage angle of a horn or direct radiator at the low end of its operating range iddetermined principally by the mouth or effective cone dimension. Detail of horn orcone shape have no effect on directivity when their dimensions are short with respectto the reproduced wavelengths. (i.e. the smaller the device, the more omni-directionalit will be a low frequencies).

Consider constant-directivity (CD) horns, the prevalent type today. CD hornsmaintain their nominal coverage angles over a broad though often unstated frequencyrange, a major step in directivity control over classic radial/sectorial (and to a lesserdegree) multicell horns. "Coverage angle" in these is the angle included by the the 6-dB-down points on a horn's far-field polar response (down from "hot", on-axis level),also called the "6-dB-down beamwidth". (Agreement on this definition is pretty-much industry-wide.) CD horns have a "break frequency" below which the coverageangle is no longer controlled but "balloons out," doubling with every octave loweringof frequency. There is a simple formula for break frequency:

f = 1,000,000 / (x)(a)

where f = approximate break frequency in HZ, x = dimension of the mouth in thesame plane as the nominal coverage angle, and a = nominal coverage angle in degrees.

The formula shows that low break frequencies tend to be associated with large hornsand wide coverage angles.


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From this formula, here is an illustrative table for a variety of Altec and Electro-Voicehorns and systems presented in Appendix I

Calculated Break Frequencies for a variety of Altex and Electrovoice Horns

Horn

Dimension

Nominal Beamwidth Approximate Break Frequency

16 in. 90 694 Hz

16 in. 60 1,042 Hz

16 in. 40 1.,563 Hz

16 in 20 3,125 Hz

32 in 90 347 Hz

32 in. 60 521 Hz

32 in 40 781 Hz32 in 20 1,563 Hz

Specific Guidelines to Narrow the "Angular Zone of Interference"

ArraySHOW makes it easy to illustrate the following guidelines by building actual

examples.

1. Splay the box axes so that the 6-dB-down beamwidths just touch, e.g., for60boxes, the box axes should be 60 apart. For the typical trap box, thismeans with rear box edges touching there must be separation at the front edges-- not tightly packed.

2. The degree to which "beamwidths touching" is successful increases as thedevice break frequency decreases. For example, a nominally 60 box with ahorn 16 inches wide has a break frequency of approximately 1,000 Hz. Thus,there is still lots of overlap to cause lots of interference in the voice range, since

the devices are simply not large enough to maintain directivity control below1000 Hz. Boxes such as the EV PI Modular series and the large Altec DTSsystems, with horn mouth dimensions in excess of 30 inches in both directions,improve things by only about 1 octave (to 500 Hz), on par with "old fashioned"large-format CD horns, such as the EV HPXXXX series and the Altex large-format Mantaray horns.


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3. When high break frequencies must be used(due to customer preference orspace limitations), physically separate the devices. This reduces markedly theangular size and audible severity of the interference zone. The observer gets"in and out of it" faster. (A trick possible in some product lines is to insert anidentically-sized LF system between two MB/HF or FR systems. Physically

the result is tight-packed, but not so acoustically:

1. If high-break frequency devices cannot be separated and/or furtherimprovement is desired, employ "optimal misalignment" by introducingsignal delays on the order of 2-8 milliseconds to adjacent devices. Imagineagain the two identical and equally-powered trapezoidal enclosures viewedfrom the top and tight-packed. The physical effect of introducing and

increasing signal delay to one of the two devices is that of rotating the zone ofinterference in one direction or the other from the array axis, until it finallymoves away from the listening space. The end result is not as smooth as asingle device, but notable more so that two devices in "high interference."Practicioners of optimum misalignment do so experimentally and interactively,usually by checking the "house curve" to see what if any broadband EQadjustments may have to be made to preserve the intended spectral balance.

Some object to the "time smear" of optimal misalignment. One opinion is that thetime aberrations are typically a lesser evil than the spectral balance and coverage evils

of distance-related comb-filter interference. However, keep in mind that the timedifferences associated with the time smear of "optimal misalignment" are what causethe comb-filter nulls in the first place. Further, the delays in arrival times that causescomb-filtering are on the order of those typically used in "optimal misalignment".

Using Device Interference Constructively


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Device interference can be used constructivelyto extend directivity control tofrequencies lower than usual. A typical example would be to extend control below500 Hz, the break frequency of a typical large-format constant-directivity horn such asthe Altec MR94B and EV HP9040 high-frequency horns or the EV MH940C mid-bass/high-frequency system, to something like 200 Hz or lower. The improvements in

system performance include (1) Increased gain-before-feedback when microphonesare located under an array and both (2) increased intelligiblity and (3) tighter, higher-impact bass in reverberant environments.

A major example of constructive interference is a "dipole array" -- two sourcesseperated by some distance. This arrangement produces higher directivity in thedirection perpindicular to the physical axis of the array, to a frequency lower (1) thesize of individual sources themselves or (2) the size of the horn operating in frequencyabove the dipole allows. Some basic points follow:

Two sources vertically arrayed form a useful, horizontat "donut" of directivity whenseparated by a distance equal to one-half wavelength of the frequency of interest. Forexample, for control at 200 Hz, a separation of 34 inches is appropriate. For perfectpoint sources and exactly (and only at) one appropriate frequency, there is noradiation along the array physical axis, since the half-eavelength separation cancelsarray output in the direction of the array axis:

Vertical dipole point sources at 34" apart. Polars of dipole source at 200Hzattenuation

The 34-inch separation is determined as follows:

First, determing the wavelength for the frequency of interent, 200 Hz:

wavelength = 13,560 / frequency

where wavelength is in inches, and frequency is in Hz. 13,560 is the speed of soundin inches/second. Thus,

wavelength200= 13,560 / 200 = 67.8 inches.


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Then the half-wavelength dipole frequency is 34 inches.

At an octave below the half-wavelength frequency (100 Hz), the cancellation alongthe array axis is gone, but there is still a useful increase in directivity compared to that

of a point source or many specific individual devices operating alone. There is alsothe opportunity of crossing over to a separate, larger dipole.

Vertical dipole point sources at 34" apart. Polars of dipole source at 100Hfrequency. At higher frequenc

At an octave above the half-wavelength frequency (400 Hz), there is a narrow forwardlobe and a major lobe of equal output above and below the array axis(see below).This suggests that the useful frequency range of the dipole radiator is restricted tosomething less than an octave above the half-wavelength frequency, perhapssomething like 2/3 of an octave above, or in this exmaple, 315 Hz.

Vertical dipole point sources at 34" apart. Polars of dipole source at 400Hfrequency. At higher frequenc

An interesting possible improvement to the situation noted in the above paragraph isemploy a tripoleradiator, with the same overall dimension, at twice the dipole half-wavelength frequemcy. This would be equivalent to being at a crossover frequecyfrom the dipole to a centrally located MB horn at twice the diple half-wavelengthfrequency. Note: for this technique to be successful, appropriate amplitude shading isrequired.


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ArraySHOW makes it easy to see how the ideas descrived above work.

Additional Comments

The interference effects descrived can be easily tested and demonstrated in the field,indoors or out. A typical demo would go something like this:

1. Place two small, identical trapezoidal systems on a turntable (projector standsand road cases work great). A typical choice would be the prevalentapproximately 15 side draft angles and 60 horizontal coverage. (In this case,"small" is stated --say a 12 or 15 inch two-way or three-way -- so the effect ofbreak frequencies of 1,0000 Hz and higher can be heard.)

2. Drive both with a pink noise signal of identical level and polarity, with theoption of introducing signal delay in the systems.

3. With no delay, tight-pack the boxes, rotate the array in front of the observer,and listen to the interference effects.

4. Still with no delay, separate the front edges to achieve a horizontal splay angleof the boxes equal to the nominal horizontal coverage angle. Again, rotate thearray in from of the observer. You will hear reduced interference. A variationof this is to keep the box sides together (paralell), but move the box a fewinches forward or backward.

5. Still with no delay, separate the boxes left to right, perhaps the amount of a"ghost box" in between them. Rotate. You will hear reduced intereference.

6. Tight-pack the boxes again, but introduce 3 ms of signal delay to one box (3msnormally works well, but you can try other amounts of signal delay up to 8ms).You will hear reduced intereference.

ArraySHOW Seminar Video Tape

EVI Audio sponsered an Array presentation at the 1997 Charlotte, North CarolinaNSCA Expo. This approximately 1.5 hour presentation featured Mark Ureda,consultant to EVI Audio, acoustics/audio consultants Bob Coffeen and Craig Janssen,with Jim long as moderator. The event was edited to video tape, available for $25

plus shipping from Customer Service, EVI Audio at 800/234-6831.

Historical Comment
http://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Specific_Guidelines_to_Narrow_thehttp://c/Program%20Files/Programas%20de%20Audio/ArrayShow/Doc/ArraySHOW%20Help.html%23Specific_Guidelines_to_Narrow_the


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Arrays of "old fashioned" large-format horns, with their large and differingdimensions, achieved basically automatically many of the guidelines noted above,e.g., separation of sources. Small trapezoidal full-range systems make this moredifficult to achieve.

"Perfectly Arrayable Boxes"

One or two manufacturers have introduced product lines touted as "improved" or"perfectly" arrayable. These appear to be boxes with draft angles equal to one-half thenominal horizontal coverage angle. This is certainly a step in the right direction, butthe break frequency of the devices cannot be ignored. For example, a horizontal angleof 40 with draft angles of 20 would appear to be a nice solution. But in a 40 boxwhich is barely wider than a 15-inch speaker, the break frequency will be so high (on

the order of 3,000 Hz or higher) that lots of overlap interference still occurs in themiddle of the voice range. Those laws of physics again!

Appendix I: Table of Device Physical Dimensions


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ArraySHOW and manual copyright 1998-2004 EVI Audio, Inc

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