White Paper Guido Noselli

System

__________________________________________________________________________________

Introduction I n t he Sound Reinforcem ent world in recent years, a great deal has been said and writ t en about vert ical line arrays. All m anufact urers, from t he sm allest t o t he largest , have brought out in a m ore or less efficient and objective manner these particular sound syst em s, each t rying t o influence list eners or readers as t o how his const ruct ion choices were t he right ones. The proliferation of "com m ents" certainly inform ed members of the public, educating them on this particular issue, and avoided people like myself (among the last to talk about them ) having to dedicate endless pages to a detailed description of the theory behind vertical line arrays. This also eliminated any temptation I might have had to criticize other m anufacturers products, because a lot of others have already done so in the com m ents circulating in the audio community for some time. On t he cont rary, I ll offer as exam ples t he product s of som e m anufact urers, dedicat ing som e space t o t hem , because t heir part icular product s in t his field give indispensable help in underst anding t he work and result s achieved by Out line, described in t his publicat ion. A great deal of what is writ t en in t his whit e paper is t aken direct ly from t he t ext and designs cont ained in som e pat ent s for t he But t erfly system, applied for in 2002.

Preliminary remarks Before Christ ian Heil ( Ref.1) , Vert ical Line Array was sim ply t he definit ion used t o appropriat ely describe a part icular t ype of enclosure: a speaker colum n. An enclosure st ill used t oday several decades after its demise, for the speech reproduction in reverberant environm ent s and all t hose places in which it s necessary t o proj ect speech over a considerable distance with good intelligibility. To dat e, t hese colum ns haven t undergone any furt her t echnical developm ent t o m ake t hem suit able for wider m ore dem anding use, such as t he wide range reproduct ion of t he whole audio spect rum in the pro audio reinforcement field.

The reason for t his and it s int rinsic charact erist ics, which m ade it and st ill m akes it an enclosure able t o reproduce wit h a virt ual dispersion of a cylindrical nature, wit h an adequat e sound level and qualit y, a rat her sm all port ion of t he audio spect rum , i.e. t he frequency range norm ally described as Vocal or Telephone Band .

This is also t he case wit h t he colum ns called I nt ellivox designed during recent years by Duran Audio ( Ref.2) , for which a sophist icat ed DPS cont roller was im plem ent ed enabling t o achieve very high direct ivit y values on t he vert ical plane, even if in a narrow band of t he audio spect rum , nevert heless m ore t han sufficient for solving speech int elligibilit y problem s in environm ent s wit h high reverb levels. Going back t o t he field which int erest s us, in spit e of all his denigrators and the sceptics who attacked him in every way, everybody has t o at t ribut e t o Heil, t he invent or of t he V- DOSC, t he rediscovery and m odern profitable application from the acoustic point of view, of the principles which are at the basis of vertical line arrays, t hanks t o which t hey can be used in widerange applications, in sound reinforcement in general and in particular in the high performance high quality market.

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 1

Nowadays, the term vertical line array is used to describe a particular sound reproduction system , which has nothing to do with the classic vocal speaker column, apart from construction sim ilarities, which consist the colum n s use of a num ber of norm ally sm all loudspeakers, m ounted alongside and one above each other and, in the case of the m odern line array, the use of a num ber of com plete enclosures, also m ounted alongside and one above each other and able to reproduce the entire audio band or, m ore generally speaking, a very wide part of it (norm ally without the low frequencies). I n t his configurat ion, t he syst em has a virt ual cylindrical acoust ic em ission caused by t he effect of t he vert ical coupling of t he m ult i- way enclosure elements forming the array. I n fact , t he use of several channels, wit h each loudspeaker dedicat ed t o a specific audio range, for t he const ruct ion of vert ical line arrays isn t a idea recent ly int roduced by Heil, but had already been experim ent ed and used for m any years in various models of speaker columns. 0ne good example is described in Ref.3 Merit t herefore shouldn't go t o Heil for having int roduced t he use of m ult i- way syst em s form ing vert ical sound line arrays, but rat her t he fact of having clearly described and dem onst rat ed t he crit eria t hat govern t hese configurat ions, arriving at t he form ulat ion of a com plet e t heory, based on t he sim ilarit ies bet ween acoust ics and opt ics wit h reference t o t he Fresnel and Fraunhofer diffract ion. ( Ref.4 and 5). This is t he acknowledgm ent t hat t he int ernat ional audio com m unit y m ust right ly and obj ect ively give Heil and this, at the same time, is the contribution of knowledge he m ade t o t his sect or and can now be used by everybody. I n fact , like ot hers in t he past , such as Olson and Beranek, to mention the most famous (Ref. 6 and 7), his work once again clarifies how difficult or im possible it is, using ort hodox m et hods, t o build a vert ical line array which works well over t he ent ire audio band, up t o high frequencies of t he order of 15/20 kHz.

From t he point of view of t heory, t here s cert ainly not hing new t hat ( even if in a different less st ylish way perhaps) hadn t already been explained fift y years ago in the books quoted. From t he point of view of pract ical realizat ions however, Heil int roduced a new elem ent , for which he deposited the patent in France in far- off 1988 and lat er in Europe and Am erica ( Ref. 8) , t he im port ance of which was such as t o relaunch t he vert ical line array as a highly effect ive const ruct ive solut ion for professional high- powered enclosures; t he sam e one t hat had been abandoned aft er t he first at t em pt s m any year before in t he pro audio world and lim it ed, as we ve seen, t o a m ore rest rict ed use in t he aforementioned speaker columns. The new elem ent is a special wave guide - t he D OSC w a ve guide , which resolves a problem which up unt il t hen had been insurm ount able, of obt aining from a high frequency loudspeaker a high sound level em ission, suit ed t o building vert ical sound colum ns for use at concert s and in general for sound reinforcem ent in large areas . Before describing Heil s invent ion and it s peculiarit y, it s necessary t o out line, at least briefly ( t he books m ent ioned can be consult ed for t he det ails) , t he m ost im port ant feat ures of a line array, wort hy of being defined as such wit h reference t o t he elem ent s that form it.

Vertical Line Arrays work Since vertical line arrays for sound reinforcement are form ed by a cert ain num ber of elem ent s/ enclosures assem bled one above t he ot her but operat ing individually, it s clear t hat t he operat ion of a syst em like t hat is closely linked wit h t he acoust ic coupling achieved bet ween all t he elem ent s wit h reference t o the audio range to be reproduced. I n short , one can t alk of acoust ic coupling when t he em ission of t he elem ent s form ing t he line array ( com parable t o t he em ission t ypical of point sources, wit h reference t o t he highest frequency t o be reproduced) int eract , sum m ing t he energy em it t ed individually. I n order for t his t o occur, which is at t he basis of t he syst em s efficient operat ion, t wo fundam ent al crit eria m ust be respect ed ( Heil cit es t hree m ore, which in this cont ext it s superfluous t o m ent ion and of which, t hose of you who wish can easily find t he descript ion in his publications): a) The sur fa ce occupie d by t he a ct ive sour ce s for m ing t he a r r a y e le m e nt s m ust n t be le ss than 80% of the total surface of the array. b) The sour ce s m ust t h e r e for e be close ly coupled and separated by a distance of no more t ha n ha lf a w a ve le ngt h r e fe r r e d t o t he highe st frequency they have to reproduce.

So didn t H e il s w or k give a nyt hing ne w , j ust a be t t e r k now le dge of w ha t w a s t he st a t e of t he art?

These t wo requisit es, if sat isfied sim ult aneously, m ean t hat a cert ain num ber of sources ( com parable wit h t he point sources at t he frequencies t hey have to reproduce) generate in the coupling plane a sound wave similar or equal to the planar wave, as happens in a sound source which is effectively planar with the

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 2

sam e dim ensions, a fundam ent al condit ion for obtaining a virtually cylindrical wavefront. When t he second of t hese condit ion can t be achieved for geom et rical reasons illust rat ed furt her ahead, as it s im possible t o obt ain t he necessary coupling which m akes t he group of em issions com parable wit h t he em ission of a planar wave source, at least am ong t he em ission of t he single elem ent s form ing t he array, it s necessary t hat no dest ruct ive int erference is generat ed in t he band of frequencies for which t he aforem ent ioned coupling couldn t be achieved. I f t he requisit es list ed so far are easily achieved for low frequencies, it s m ore difficult for m id frequencies, t o avoid dest ruct ive int erference at 1000Hz, for exam ple ( 1/ 2 wavelengt h = approxim at ely 17cm .) , t his would im ply t he use of sources t hat don t exceed t he dim ensions of 17cm ( a 6.5 speaker) , wit h all t he result s in t erm s of poor efficiency. Then, for frequencies above 1000Hz, t he dim ensions of the sources must gradually diminish to values that are only t heoret ical and m at erially im possible t o achieve with real sources such as loudspeakers.

Ve r t ica l line a r r a ys w e a k poin t I t can be seen from all t his t hat t he form at ion of a vert ical line array has it s weakest point in t he high frequencies or rat her in how t he act ive com ponent, loudspeaker or ot her it em t hat has t o reproduce them is made and used. I n fact , for exam ple, t o reproduce frequencies up t o 10000Hz ( 1/ 2 wavelengt h = 1.7 cm ) , sources t hat don t physically exceed t his dim ension would have t o be coupled closely. Even supposing t hat such sm all loudspeakers ( m agnet ic circuit ry included) can be built , it s easy t o im agine t hat it would be a wast e of t im e, due t o t he pract ically non- exist ent efficiency of loudspeakers of that type. Creat ing vert ical line arrays t hat operat e well at high frequencies t herefore becom es a pract ically insurm ount able physical quest ion if one want s t o use t radit ional loudspeakers such as for exam ple cone or dome units. Refer again to Fig. 2A, 2B, 2C, 2D. And also all kinds of horns are by t heir very nat ure flared duct s whose sides are divergent according t o t he required sound dispersion, and whose m out h surface dim ensions aren t negligible as t hey re suit ed t o t he lowest frequency t hat has t o pass t hrough them. This m eans t hat even reducing t he dist ance bet ween the horns, the emission centres (the throats) can still be a considerable dist ance apart , so for all t hese reasons can t be built wit h dim ensions and t ype of dispersion m ore suit ed t o form ing a line array operating correctly according to the requisites listed.

Fla t dia ph r a gm lou dspe a k e r s vertical line arrays

in

I f however one decides t o use loudspeaker t hat are slight ly less t radit ional, such as t hose wit h a flat diaphragm , in one of t he versions m anufact ured t oday ( elect rost at ic, isodynam ic, et c.) , it wouldn t be difficult t o obt ain correct behaviour even at high frequencies. I n fact , it s easy t o im agine how t he behaviour of t hese loudspeakers, wit h reference t o t heir sound em ission, is t he best t hat could be im agined for forming a line of vert ical sound em ission. I n fact , t hese loudspeakers, being m ade up of flat diaphragm s t hat m ove in phase wit h all t he frequencies t hey reproduce, are com parable t o sm all line array, and t he inst allat ion of one sm all line array on anot her sm all line array can only result in t he form at ion of a higher line array wit h em ission of planar sound waves on t he coupling plane. Unfort unat ely, due t o t he current st at e of t his technique, their intrinsic construction means that this t ype of loudspeaker doesn t have sufficient power handling capacit y for t he high sound pressure levels required from pro line arrays able t o cover large areas as far as both width and depth are concerned. For t his reason t hey re not widely used, and can generally only be seen in m odels wit h lower performance.

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 3

Com pr e ssion dr ive r s in ve r t ica l lin e arrays So, what can be used t o reproduce high frequencies that meets the necessary requisites? Since t he m ost im port ant requisit e, as has been seen, is the capacity to reproduce sound pressure, of all t oday s known com ponent s t he m ost efficient and t hat which is m ost suit ed t o obt aining it are com pression driver. However, like ot her t radit ional loudspeakers, it doesn t have negligible dim ensions, or sound em ission com parable wit h t hat of a rectangular flat diaphragm. Therefore, m any m anufact urers t ried t heir skill at m aking special wave guides or part icular acoust ic adapt ors t hat enabled t he easily available com pression drivers in m ult iples t o reproduce t he high frequencies in line array systems.

This em ission slot can in t urn becom e t he t hroat of a furt her coupled horn or wave guide, in order t o control dispersion on the horizontal plane. The aim of t he phasing plug is t o get t he em ission of every point of t he circular t hroat plane of t he driver t o reach t he new rect angular t hroat plane at t he end of t he wave guide, t he diffract ion slot , covering t he sam e dist ance, in such as way as t o reproduce t he sam e planar wave found at t he t hroat of a com pression driver in rect angular rat her t han circular form. The dim ensions of t he annular duct are very sm all and t herefore avoid creat ing dest ruct ive int erference due t o int ernal reflect ions bet ween t he walls of t he wave guide and t he phasing plug . Fig. 6A, 6B, 6C and 6D schem at ize Heil's innovat ion. I t s obvious t hat t his elem ent sim ulat es t he cylindrical wavefront of a rectangular flat diaphragm very closely. I n part icular, Fig. 6 A shows a horizont al cross sect ion of a driver wit h phasing plug; Fig. 6 B shows a vert ical sect ion of t he sam e driver wit h phasing plus; Fig. 6 C is an axonom et ric view showing t he driver wit h phasing plug wit h t he out put slot coupled t o a front horn or wave guide; Fig. 6 D is t he diagram of t wo unit s wit h phasing plug aligned one above the other to give a cylindrical wavefront. I t seem s clear t hat Heil s syst em is geom et rically exem plary and essent ially correct for achieving t he result , com pared t o t hose less correct ones based on coupling various wave guides, horns, et c. And in fact , t he perform ance of t his syst em , in m y opinion is at the basis of the success achieved by the product on which it s used.

But as can be easily deduced from t he schem at ic exam ples on t hese pages, apart from t he m ore or less good acoust ic result s obt ained, no device inspired by t hem fully achieves what is required by t he line array t heory: sound em ission by a rect angular flat diaphragm . The sim plest m ost efficient solution for generating planar waves.

I s t h e D OSC w a ve gu ide t h e on ly possible solution? The t echniques illust rat ed up t o now or sim ilar ones sim ply enable t o reduce t he effect of int erference t hat occurs bet ween t he elem ent s, t aking t hem t o t he highest possible frequencies t heir physical dimensions will allow. Heil s wave guide on t he ot her hand offers an innovative valid way of achieving the aim described: Sim ula t ing t he be ha viour of a r e ct a ngula r fla t dia phr a gm using a cla ssic com pr e ssion dr ive r The syst em foresees a wave guide t hat receives t he com pression driver s em ission via a phasing plug elem ent , which in t urn creat es wit h t he sides of t he wave guide a narrow circular duct at the throat plane where the sound is emitted, transforming it gradually int o a rect angular annular duct finishing in t he sound output slot.

Other valid solutions? The Reflective Wave Guide Only recent ly, a new solut ion was found. Aft er several years during which t here was first ly confusion in t he pro audio sound reinforcem ent m arket on behalf of t he m aj orit y of t he world s m anufact urers regarding t he use of line arrays and later t heir m obilisat ion in t he search for new m ore or less valid products to be put on the market, following up on t he success t hat Heil s product s cont inued t o have year after year.

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 4

Perhaps t his new solut ion isn t as t ot ally irreprehensible from a geom et rical point of view as Heil s invent ion, but anyway in m y opinion it s m ore valid t han t he ot hers t hat have been put forward up unt il now since, based on a com plet ely different principle, it enables t o realize a high frequency sect ion which perform s very sim ilarly t o a source wit h a rect angular flat diaphragm , which I wish t o repeat, is the solution most suited to use in a vertical line array. I n fact , if one looks closely, t he solut ion found allows t he form at ion of sound em ission not only for planar waves, but also convergent and divergent waves according to construction needs. At t his point , I d like t o st at e t hat t his innovat ion was t he alm ost sim ult aneous subj ect , unbeknown t o it s invent ors, of t wo pat ent applicat ions, bot h valid for pat ent law, as t he m ost recent was present ed before t he publicat ion of t he previous one, during t he socalled lat ency period which, unless expressly request ed by t he invent or, norm ally last s for 18 months. One applicat ion is I t alian, N ° BS2 0 0 1 A0 0 0 0 7 3 da t e d 0 3 / 1 0 / 2 0 0 1 , deposit ed by Out line, which I represent , t he ot her is t he French N ° 0 0 1 1 4 9 of 08/09/2000, deposit ed by Eric Vincenot and Francois Deffarges, t wo nam es t hat don t require any introduction. The operating principle of this wave guide, which can generally be defined as reflect ive , suit ed t o be used t o advant age not only in vert ical line arrays, is schem at ized respect ively in t he group of diagram s from 7A t o 7E, as far as t he designs illust rat ing t he application for an Italian patent are concerned,

in t he Fig. 8 group, as far as t he designs illust rat ing the French patent application are concerned,

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 5

The operat ing principle is based on t he reflect ion of t he sound em it t ed by t he com pression driver s t hroat by m eans of a flat , parabolic, hyperbolic or ellipt ical surface, according to the type of dispersion required. Before being reflect ed, t he sound em it t ed by t he driver s circular t hroat passes t hrough a wave guide form ed on one side by parallel, convergent or divergent walls and on t he ot her by walls which diverge conically or wit h anot her geom et ric flair, in order t o form ( at a given dist ance from t he init ial t hroat ) anot her so- called diffract ion t hroat wit h a rect angular shape ( a slot ) , posit ioned j ust before or j ust aft er t he reflect ing surface port ion, creat ing planar, divergent or convergent sound waves. As well as advant ages which can be easily im agined by looking at t hese illust rat ions, t his solut ion offers doubtless advantages of a geometric nature, because folding t he high frequency wave guide ( norm ally st raight t o avoid creat ing dest ruct ive int ernal interference) close to the reflecting surface facilitates reduction of the dimensions of the enclosure in which its fitted. What s m ore, it s acoust ic operat ion, at least in t he case of t he parabolic reflect ing surface, resem bles t hat of t he flat diaphragm it t ries t o im it at e. I n fact , a parabola works according t o t he diagram shown here,

However, closely analysing t he geom et ry of t he device proposed in t he aforesaid pat ent applicat ions, one realizes t hat t he im it at ion of flat diaphragm em ission isn t com plet ely successful and doesn t achieve t he degree of perfect ion t hat on t he cont rary t he geom et ry used by Heil enables his device t o achieve. I n fact , t he reflect ing parabolic surface, described as being able t o t ransform t he spherical planar sound wave em it t ed by t he com pression driver int o a rect angular planar sound wave, which is t he prerequisit e for form ing vert ical line arrays perform ing well at high frequencies, needs, for t his to t ake place, a source which is e ffe ct ive ly a point source and doesn t have dim ensions such as t hat of a driver s t hroat . I n fact , analysing t he parabola by m eans of t he schem at ic designs, it can be not iced t hat , due t o it s shape, it can t reflect in parallel beam s t he sound em it t ed by any source ot her t han a point source posit ioned in it s focus and t herefore, in t his case, can t com e close t o flat diaphragm s operat ion for planar waves. I t also seem s clear t hat t he pat hs from every point of t he source t o t he em ission surface ( shown wit h a darker line in t he illust rat ions) can t rem ain t he sam e, as is necessary t o avoid t he occurrence of t he t ypical int erference caused by different arrival t im es of the signal reproduced by the device.

and is able t o concent rat e planar sound waves cut t ing it s surface in it s focus and/ or em it planar waves st art ing from a point source put in t he sam e focus, m aint aining an ident ical signal pat h from t he source to the emission plane in question

This also happens in t he case of t he reflect ing wave guide in the aforementioned patent applications.

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 6

I n fact , since t he real sound em ission is not point source em ission, virt ual point source em ission can t be form ed out side t he wave guide for any of t he possible reflecting surfaces, including parabolic. A glance at Fig. 9 B1 , 9 B2 , 9 B3 , regarding a hyperbola, will clarify t he concept bet t er t han any more written explanations.

Then, wit h reference t o t he ellipse, see Fig. 9 C1 , 9C2, 9C3.

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 7

I n shor t , t he condit ions for opt im um sound r e fle ct ion, t hose st r ict ly com pa r a ble w it h t he or e t ica l condit ions, pa r t icula r ly t hose a llow e d by a pa r a bola , w hich is t he r e fle ct ing sur fa ce by m e a ns of w hich it s possible t o a ppr oa ch t he e m ission condit ions of a fla t dia phr a gm , a r e only e ffe ct ive ly a nd t ot a lly achieved if the source is a point source. When t he real source has dim ensions can t be overlooked ( in t he professional sound reinforcem ent sect or, t hese dim ension can t be reduced below a cert ain lim it for reasons of power) , t he sound emission obtained using the reflection method gets furt her and furt her from achieving t he em ission charact erist ics of a flat diaphragm t he larger t he source s dim ension and t he higher t he frequency band to be reproduced by reflection. I t can be deduced t hat from a t heoret ical and pract ical point of view, t his m et hod doesn t have t he geom et ric precision of Heil s wave guide and t herefore it s use in m ult iples for HF sect ions in vert ical line arrays will increase t he im perfect ions which occur in t he syst em for physical reasons which can t be overcom e, even if t he result is st ill pot ent ially bet t er t hat t hat which can be achieved adopt ing ot her classic solut ions found up unt il now, as t hey re also condit ioned t o a great er ext ent by unavoidable geometric/physical questions. I n m y opinion, t he solut ion described t o far, based on folding t he wave guide t o achieve t he required t ype of reflect ion having a real source like t he t hroat of a driver, can be bet t er exploit ed t o build part icular single enclosures which don t necessarily have t o be coupled in m ult iples, such as for exam ple very low profile wedge m onit ors , in which it s im port ant t o keep t he physical dim ensions wit hin necessary limits. I personally used t his syst em for our H.A.R.D. 212, no com prom ise wedge m onit ors wit h a very low profile and wit h ideal acoust ic/ direct ive characteristics for short/medium throw applications. Aft er t hese observat ions, if I ve m anaged t o explain m yself sufficient ly clearly, it 's obvious t hat in spit e of t he lat est ( nevert heless valid) solut ions t o t he problem of reproducing high frequencies in vert ical line arrays , t he DOSC wave guide offers great er precision and it s perform ance is m uch closer t o t hat of a flat diaphragm. Is there therefore absolutely no possibility of building a device t hat perform s in t he sam e way as Heil s

wit hout using t he sam e const ruct ion logic safeguarded by its patent? I n recent years, t he search for t his device has been t he obj ect of research and const ant work at Out line wit h count less prot ot ypes being built , of bot h very com plicat ed individual devices and equally com plex complete units containing these devices, as the latter were necessary for carrying out measurements which are really indicat ive of t he acoust ic result s obt ained using them in line arrays. This int ense work led t o t he discovery of a new solut ion t o t he problem , wit h t he invent ion of a device whose pat ent applicat ion, regist ered in I t aly som e t im e ago, has been ext ended t o international level (PCT). The device s operat ion is ext rem ely sim ilar t o t hat of a flat diaphragm , at least t o t he sam e ext ent as Heil s wave guide, wit h which it has no principles in common. In fact, the new device combines operation similar to t hat of a flat diaphragm wit h t he m uch wider versat ilit y and pot ent ial of t he reflect ing wave guide already described, as it exceeds it in precision, emission coherence and overall performance.

N ose lli s D PRW G, D ou ble Pa r a bolic Re fle ct ive W a ve Gu ide as an altern a t ive solu t ion t o H e il s D OSC wave guide. The solut ion, which had been sought for so long and has at last been found, like all valid solut ions, is of disarming simplicity. I t s applicat ion allows loudspeaker syst em designers wide working m argins from t he const ruct ion point of view and m uch great er creat ivit y regarding enclosures shapes, up unt il now based on t he classic solution imposed by well- known techniques. I n short , t his device, built on t he basis of t he invent ion, allows t o overcom e t he int rinsic lim it s of a geom et rical and dim ension nat ure of t radit ional cone speakers, dom e t weet ers and com pression drivers also and above all used t o build line arrays, or t hose syst em s in which t he correct acoust ic coupling of m ult iple sources is indispensable t o achieve t he result. The inve nt ion is ba se d on t he t r a nsfor m a t ion of a sour ce w it h t he t ypica l dim e nsions of r e a l loudspe a k e r s, fir st ly int o a vir t ua l point sour ce w it h cha r a ct e r ist ics ide nt ica l t o a r e a l point sour ce a nd la t e r , in a se cond st a ge , obt a ining fr om t his real point sour ce t he r e quir e d sound dispe r sion by m e a ns of r e fle ct ion w it h va r ious t ype s of sur fa ce s w it h diffe r e nt sha pe s, k e e ping t he sound pa t hs e x a ct ly t he sa m e fr om a ny point of t he a ct ive sour ce t o t he m e a sur e m e nt or list e ning posit ion via t he reflecting surface. This r e fle ct ing sur fa ce ca n be fla t , pa r a bolic, hype r bolic or e llipt ica l, or m or e ge ne r a lly speaking, flat, concave or convex. I t s m uch harder t o describe t he device in words t han with the following diagrams. Fig. 1 0 A, 1 0 B, 1 0 C, 1 0 D a n d 1 0 E schem at ize t he t ransform at ion of a real flat source ( represent ed in

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 8

all t he diagram s by a cont inuous segm ent on a dot t ed st raight line) int o a real point source by m eans of a parabolic concave reflect ing surface and also schem at ize t he sound diffusion in t he direct ion of t he arrows by m eans of t he sam e parabolic (convex) surface (Fig. 10A), a flat surface (Fig. 10B), a hyperbolic ( concave) surface ( Fig. 10C) , a parabolic ( concave) surface ( Fig. 10D) and an elliptical (concave) surface (Fig. 10E);

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 9

Fig. 11C shows the cross-section of a practical example of the double reflective wave guide in which separators have also been m ounted in the duct to elim inate any possible internal interference at high frequencies.

Fig. 1 1 D shows yet another exam ple, which can be achieved by the revolution of the section of the wave guide shown in Fig. 11A

From a graphic point of view, t he behaviour of t he device can be seen in t he following diagram s. 11A, 11B schem at ize axonom etric diagram s of som e exam ples of acoustic reflectors which reproduce the various aspects of the invention.

Fig. 1 2 schem at izes anot her possibilit y offered by t he invent ed syst em , showing it s great pot ent ial: t he t ransform at ion of a real signal source int o a real point source which, by m eans of ot her t wo com bined reflect ing surfaces, is t ransform ed int o a source which is planar or of anot her t ype, but nevert heless keeping the signal paths the same length.

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 10

There are a lot m ore possible com binat ions which, in order t o increase t he sound pressure level, use several real sources simultaneously, whose emission, using t he sam e m echanism , is direct ed and reflected outwards with the required dispersion. But , aft er what has been described up unt il t his point , I ll leave it t o you t o im agine t he num erous possible configurations this technique offers. The first practical application of the device described, the DPRWG- Double Parabolic Reflect ive Wave Guide, in one of it s possible variat ions, is found in the C.D.H. 483 Butterfly Hi- Pack. Here below t here is a pict ure of part ially disassembled one.

Definit ely t he m ost int erest ing part t o be found in t his elem ent / enclosure, built by Out line for m ult iple use in vert ical line arrays, because, as I t hink I ve clearly shown, it s a good solut ion t o t he problem of reproducing high frequencies in this type of system. However, with the Butterfly Hi- Pack all the necessary geom et ric and m echanical solut ions have obviously also been adopt ed t o ensure t hat t he rest of t he audio spect rum , not ent rust ed t o t he high frequency sect ion, is reproduced wit h t he sam e qualit y and precision. So all t he const ruct ion st rat agem s were chosen and applied in order t o m eet t he requisit es im posed by line array t heory, even exceeding t hem wherever possible. The following designs show t he definit ive single and array versions of the Butterfly C.D.H. 483.

The first t hing one not ices looking a t he above design is the external shape of the Hi- Pack, for which applicat ion has been m ade for an int ernat ional indust rial design pat ent , result ing in t he product being called But t erfly for t wo reasons; first ly, because t he shape brings t o m ind t hat of a but t erfly and secondly because it is also very light weight : in fact , considering t he fact t hat it s equipped wit h no less t han five loudspeakers, it s weight is approxim at ely 33kg, including flying hardware fit t ed as standard. The second innovat ive fact , also t he subj ect of an indust rial design pat ent applicat ion and also an applicat ion for an invent ion pat ent along wit h t he DPRWG wave guide, consist s in t he t ot al lack of t op and bot t om panel defining t he horn cavit y in front of the diffraction slot. The aim of t his was clearly t o facilit at e t he coupling of t he arrays com ponent s up t o t he highest frequencies, keeping t he sm allest possible dist ance bet ween t he sources and at t he sam e t im e offering t hem a loading baffle wit h appropriat e unint errupt ed lines, an effect ive st rat agem for m inim izing diffract ion and alt erat ion of t he response in t he m id/ high range due t o gaps which can t be overlooked. The horn itself, or rather the sides of the horn, which est ablish t he syst em s horizont al dispersion, finish wit h sm oot h curves m eet ing up wit h t he box s ext ernal sides, which are also rounded and raked

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 11

t owards t he rear of t he cabinet and anot her innovat ion from a design and t echnical point of view. I n fact , t hese geom et ric and const ruct ion feat ures have t wo aim s: m inim izing any diffract ion at t he m out h of t he horn and at t he sam e t im e great ly st rengt hening t he side walls of t he box, which ( as well as all t he rest ) also cont ains a bass sect ion wit h bandpass configuration and two dedicated speakers. The box is built in com posit e plywood, obtained alm ost ent irely via m oulding and high frequency gluing. The panels t hickness has been lim it ed t o 14m m . t o reduce t he enclosures weight , but at t he sam e t im e im prove overall rigidit y and elim inat e any resonance t hat m ight be caused by t he low frequency section. The flying hardware allows t o vary t he angle bet ween t he elem ent s wit h m inim um st eps of as lit t le as 0.1 degrees if necessary; t he m inim um standard step is 0.25 degrees. The dimensions and the materials used have enabled t he unit s t o be cert ified, according t o t he st rict est int ernat ional norm s, for flying up t o 32 Hi- Pack syst em s in a Vert ical Line Array reaching a height of almost 8 metres. From t he acoust ic point of view, as well as t he groundbreaking DPRWG- Double Parabolic Reflect ive Wave Guide, it s wort h m ent ioning t hat it s a 3- way system, but only requires active biamping. One channel for t he com pression driver wit h 3 diaphragm and 1.41 t hroat , t he ot her for t he m id/ low and m id sect ions, connect ed in parallel t o passive components without any kind of crossover. By m eans of a m echanical break, achieved by m eans of t he precise rest rict ing geom et ry of t he resonance cham bers and t he respect ive t uning of t he m id/ low and m id sect ions, t he em issions phase was shift ed in order t o obt ain a coherent sum over t he ent ire reproduced bandwidt h t he t wo sect ions have in common. This technique, which required fine adjustment of the cabinet s volum es and t uning, has a great advant age, above all regarding t he array elem ent s com pact dim ensions ( 240m m . high, 700m m . wide and 600m m . deep) : in fact , it s able t o produce great energy bet ween 80 and 400Hz, which is oft en very poor in ot her syst em s wit h com parable dim ensions. An advant age which is even m ore effect ive because as it s been achieved wit h a m inim um increase in overall cost and weight. I n fact , t wo ext rem ely light 8 neodym ium speakers are use in t he m id/ low sect ion in a rat her unusual posit ion and wit h t he m agnet facing out int o t he t uned cham ber t o ensure efficient m agnet ic circuit ry cooling by m eans of t he vent ilat ion creat ed by t he movement of the cone itself. The sound em ission of t hese speakers, which are in bandpass configurat ion, has been fed int o t wo large front slot s at t he ext rem it ies of t he box, in such a way as t o be sum m ed evenly and perfect ly wit h t he em ission of t he m id sect ion, which in t urn faces out from t he sides of t he horn in a posit ion which is symmetric with the sides of the diffraction slot. The sect ion com prises t wo m ore 8 speakers, in t his case in ferrit e for bet t er heat dissipat ion, since t hey ve t o m ove less t han t hose already described, as t hey re dam ped by a sm all rear loading volum e t uned t o raise t heir resonance, in order t o obt ain greater efficiency in the mid range reproduced by the two cones.

Horizont al dispersion is 90° in t he definit ive syst em , while t he prot ot ypes were built wit h a slight ly narrower angle. The horn used for t his has rat her enviable dispersion behaviour: for one t hing, it s const ant over t he ent ire frequency range reproduced and t he off- axis level rem ains high up t o nom inal dispersion, indicat ed in t he case of t he prot ot ypes as approxim at ely 80° , aft er which it drops decidedly; t his indicat es it s efficiency as far as directivity is concerned. There again, t he m out h has am ple dim ensions (approxim at ely 50cm . before it curves round t o j oin t he rear panel, which m eans t hat at 700Hz t he horn already has a suit able dim ension for t he cont rol of dispersion and at 1400 ( 1/ 2 ) , cont rol is com plet ely achieved. Vert ical dispersion is obviously est ablished by the height and aperture of the array element. I ve included a polar plot m easured on t he horizont al and vert ical plane on a prot ot ype, t o highlight behaviour at som e significant band- centre frequencies.

The prelim inary charact erist ics for a single elem ent in its standard version are as follows: Operating frequency range 80÷18000 Hz Nominal dispersion 90° horizontal Loudspeakers low range mid range high range

2) 8 Neodym ium 2) 8 Ferrite 1) 3 com pression driver - 1.41 t hroat

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 12

Sensitivity 1W/1 m low mid high

98 dB 103 dB 110 dB

Continuous power handling - Hi- pass enabled low 400WAES mid 400WAES high 120WAES Continuous spl calculated - 1m Low/mid 132 dB SPL High 131 dB SPL Peak spl calculated - 1m Low/mid 138 dB SPL High 137 dB SPL Up unt il t his point , I ve illust rat ed as sim ply as possible and wit h t he m ost underst andable im ages t he innovat ive original t echnology t hat Out line uses for this new product.

But t e r fly Low - Pa ck C.D .L. 1 8 1 5 From t he prelim inary charact erist ics given for t he HiPack, it s obvious t hat t he syst em m ust be used wit h a bass system matching its characteristics. The Out line range has at least t wo product s t hat could excellent ly com plem ent t he syst em , wit h perform ance definit ely up t o t he sam e st andard; t hey re Vict or Live and TopSub Plus. Bot h are fit t ed wit h t wo 18 w oofers in classic reflex configurat ion in enclosures t hat are very com pact in spit e of t he reproduction high level of very low frequencies; if necessary, Vict or Live can be flown for great er versatility. Perform ance specs can be found in Out line s technical documentation. I n spit e of t his, it was decided t o include in t he But t erfly series a new low frequency syst em for use along wit h t he Hi- Pack, sharing it s funct ionalit ies. I n fact , t he new syst em s box is designed and built wit h m ult iple dim ensions as far as height is concerned and it has t he sam e foot print alt hough it obviously doesn t have t he Hi- Pack s horn cavit y . I t has t he sam e flying hardware, which m akes it perfect ly com pat ible and enables it t o also be included in main line arrays. In multiple arrays, up to 16 can be flown one above t he ot her ( if t here s sufficient space even 24! ! ! ! ! ) for a height of approxim at ely 8 m et res and a t ot al weight of approxim at ely 700kg, which can be handled by t he flying system without any difficulty. To all effect s, it s an elem ent built wit h t he crit eria necessary for form ing a real vert ical line array suit ed to reproducing low frequencies. I n act ual fact , since t he syst em was designed wit h som e special feat ures which facilit at e replacem ent of t he speakers wit h ot hers wit h a sm aller diam et er t han 18 ( t he size fit t ed as st andard) , such as for exam ple 15 or even 12 speakers, and since the box has t ruly com pact dim ensions which occupy j ust t he space of t wo Hi- Packs one on t op of t he ot her, ( 480m m . high, 700m m . wide and 600m m . deep) , wit h a net w eight of 43.5k g including it s flying hardware, t he But t erfly C.D.L. 1815 ( t he code num ber of t he basic version) , can be easily

configured t o bet t er reproduce t he required band, from t he deepest low frequencies t o t he highest m id/ lows, and adapt it t o t he m ost varied sound reinforcem ent requirem ent s, highlight ing t he versatility of the entire vertical line array. These charact erist ics alone would be sufficient t o make it a worthy match for a product such as the HiPack C.D.H. 483, but Out line, t hanks t o t he int ense act ivit y in recent years and t he result s of on- going experimentat ion, decided t o added a furt her useful det ail t o t he product : Cardioid or Hypercardioid dispersion. Designing t his t ype of enclosure for low frequencies cert ainly isn t exact ly som et hing new, even if generally speaking t he t echnology necessary for obtaining t his dispersion has been widely applied for many years to microphones. I n fact , obt aining t his dispersion pat t ern from low frequency enclosures isn t exact ly an easy j ob ( on t his t opic, I suggest som e int erest ing reading - Ref. 9). The dim ensions involved, linked wit h large loudspeakers and t he relat ive boxes t o cont ain and load t hem wit h an adequat e volum e for reproducing low frequencies, don t allow im m ediat e com pact solut ions, so t hrough t im e t here haven t been products with any real commercial success. Const ruct ion difficult ies result ing from t he reasons m ent ioned in fact inevit ably lead t o high cost s, worsened by t he fact t hat for t his t ype syst em it s also necessary t o use sophist icat ed elect ronics, normally digital. As far as I know, t o t his day on t he professional m arket , t here are only t wo brands whose product ranges include low frequency enclosures wit h cardioid dispersion or sim ilar: one is US firm Meyer Sound Laborat ory, which m anufact ures a couple of self- powered m odels; t he best known and first on t he pro m arket a few years ago was t he PSW- 6, in which no less than six large loudspeakers are used in reflex configurat ion: four for front radiat ion ( t wo 18 and t wo 15 ) , ot her t wo 15 speakers facing backwards to annul rear emission. Declared perform ance is considerable, as usual wit h t his brand, wit h a 143dB m axim um peak spl in halfspace at 1 m et re, a 30÷ 125Hz operat ing frequency range, and net weight of 200kg. it s dim ensions are 1083m m . ( W) , 1089m m . ( H) and 794m m ( D) : all t his wit h a front - t o- back rat io which is on average 15dB for the stated range. The second m odel, also of t he cardioid t ype, designed and built expressly as a line array elem ent , has four speakers ( t wo 18 for front radiat ion and t wo 15 t o annul rear radiat ion) and, even if m ore com pact and light er ( 1372m m . wide, 508m m . high, 775mm deep and a net weight of 180kg.), it also has a considerable declared perform ance, wit h 140dB of m axim um peak spl and sim ilar operat ing frequency range (28÷100Hz). The t echnology used for t hese t wo product s is relat ively sim ple from a physical point of view; in fact , t he loading syst em used in bot h t he loudspeaker sect ions, front and rear, is t he classic phase shift set- up, com m only known as bass reflex , while t he elect ronic cont rol applied t o ensure t he syst em s cardioid dispersion is com plicat ed. The Meyer Sound unit was recently joined by another brand s syst em wit h low frequency cardioid dispersion - Nexo.

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 13

I n fact , t his French firm s product range already has a couple of m odels: t he CD 12, which is fit t ed wit h t wo 12 and t he brand new CD 18, which has t wo 18 . Rather than choosing a classic method from the point of view of t he configurat ion ( bass reflex) , t he French m anufact urer obt ained good result s, considering t he declared charact erist ics, from t he applicat ion of what t o an out sider appears t o be a com plicat ed t win reflex configurat ion, also called high- order bandpass , whose operat ion regarding cardioid dispersion is necessarily cont rolled by digit al electronics which are complex and sophisticated. I n fact , a glance at t he syst em s shows t he presence on t he front of t he t uning and sound em ission port s of t he t wo cham bers foreseen by t win reflex configurat ion, st ressing t hat t his part icular enclosure s direct ivit y is som ehow obt ained exclusively using digit al elect ronics; in short , elect ronic delay and phase shift of t he t wo individual loudspeakers em ission. This sam e configurat ion is also used for the CD 18. The declared specs for t he CD 12 are 102dB ( + / 3dB) sensitivity and 134 dB (+/ - 3dB) maximum peak at 1m in half- space, t o obt ain t he which, m aking a quick calculation, peak power of no less than 1,700W is required, an operat ing frequency range from 39 t o 250Hz, a weight of 36kg, including flying hardware and a box which is 600m m . wide, 400m m high and 754mm. deep. Figures declared for t he CD 18 on t he ot her hand are: m axim um sensit ivit y 105dB ( + / - 3dB) and m axim um peak spl in half- space of no less t han 145dB ( + / - 3dB) , t o obt ain which an am plifier able t o feed out no less t han 10,000W Peak will be required!!!!!! Having seen t hat t he m arket s supply of cardioid syst em s was rat her lim it ed, Out line decided t o design it s own Cardioid syst em for t he reproduct ion of low frequencies. What bet t er opport unit y t o design and build it t han t o m at ch it wit h a vert ical line array syst em , wit h which it has very high directivity in common? Here s t he design of t he definit ive version of t he Butterfly C.D.L. 1815.

The box is built in com posit e plywood, m ainly manufact ured via m oulding and high frequency gluing. The t hickness, in spit e of what one m ight expect for a low frequency box, is decidedly lim it ed (14mm.), to keep the weight down. The egg shape of t he sides and t he split layout of t he t op and bot t om give t he box great st urdiness, t aking residue resonance out of t he syst em s operat ing range and t herefore not excitable even at the highest sound emission levels. The flying syst em enables t o vary t he reciprocal angle bet ween elem ent s and is com plet ely compatible with that of the Hi- Pack, with which it has many mechanical parts in common. Up t o now I ve explained t he physical and m echanical charact erist ics which m ake it a t echnically advanced product , but t hese favourable feat ures are com bined wit h it s cardioid or hypercardioid sound dispersion. Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 14

Like all Out line product s, t he t echnique used t o obt ain it is essent ially based on t he applicat ion of physical and geom et rical principles t o acoust ics rather than intensive use of electronic correction. I personally believe t hat t he acoust ic phenom enon is a com plet ely physical phenom enon and t herefore before using elect ronics, every possible configurat ion which could lead t o t he achievem ent of t he required perform ance is pat ient ly and generally successfully tried out for each project. The sam e crit erion was also used for t he Low- Pack and aft er num erous prot ot ypes, assessm ent s and m easurem ent on t he field, a new t ype of hybrid acoust ic loading was found, of which ( following indept h search) no t race has been found in internat ional t echnical lit erat ure regarding speaker enclosures, in particular the special type of enclosure for low frequencies wit h cardioid o sim ilar dispersion. For t his new configurat ion, a hybrid from t he physical point of view using a com plex com binat ion of int eract ing m echanical bandpass and high- pass to load the two loudspeakers, which are in a common air space, I t alian and an I nt ernat ional pat ent s ( PCT) have been applied for, support ed by frequency response polar plots and an equivalent electric circuit diagram which, as well as specifying t he t ype pat ent ed, m akes it s operat ing principle com prehensible, ot herwise difficult t o explain due t o the lack of specific publications. To highlight t he versat ilit y t hat t he t echnology used by t he syst em offers, regarding possible variat ions, in t he passband reproduced wit h t he replacem ent of t he speakers, and in t he dispersion pat t ern, wit hout any part icular elect ronic processing apart from t he use of a norm al delay , a funct ion included in t he st andard GENI US 6 cont roller, t he following acronym has been coined: AD LS Adj ust m e nt System.

D ir e ct ivit y

Loudspe a k e r

I n it s st andard configurat ion, t he syst em uses an 18 speaker for front emission and the speaker inside the box, whose em ission is used t o recreat e t he required cardioid or hypercardioid dispersion in t he syst em , is a 15 speaker. Norm alized polar response in halfspace obt ained from t he syst em are shown below (valid for the horizontal plane. On t he vert ical plane, t he syst em has a dispersion of approximately 90°, extending from the plane the box is st anding on t o an im aginary vert ical plane which int ersect s it perpendicularly behind t he enclosure ( in t his case, t he cardioid dispersion is m odified by t he plane the box is standing on, which in fact eliminates em ission in t he bot t om left quadrant of t he polar pattern). I t s wort h not ing t he uniform reduct ion of rear em ission for all frequency bands involved and t he rem arkable front - to- back rat io which, from a m inim um of 12 dB at 120Hz ( t he t op cut - off frequency suggest ed) at t enuat es t he rear em ission by over 15dB for all other frequency bands.

I m port ant diagram s and designs are shown below, including a very detailed concept diagram.

The prelim inary charact erist ics for a single elem ent in its standard version are as follows: Operating frequency range 35÷180Hz Nominal dispersion The subst ant ial com plexit y from t he point of view of the elect roacoust ic circuit used is expressed wit h ext rem e sem plicit y from t he const ruct ion point of view.

Free- field 180° horizontal/vertical

Nominal dispersion - Half- space 180° horizontal 90° vertical

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 15

Loudspeakers front rear

1) 18 Ferrit e 1) 15 Neodym ium

Sensitivity 1W/1 m Half- space

102 dB

Continuous power handling capacity enabled front 18 1000WAES rear 15 500WAES

Hi- Pass

Continuous spl calculated - 1m Microphone in front at 4 metres Half- space 132 dB SPL Peak spl calculated - 1m Half- space 138 dB SPL Front- to- back dB SPL ratio 1m Rear microphone at 4 metres Average 15 dB SPL Passband 40÷100Hz

safe array flying, t hus reducing t he risk of bad results. The t ools offered by t he various m anufact urers of line arrays are generally developed by using classic spreadsheet such as Microsoft s Excel. This great ly lim it s t he program s graphic precision, not so m uch as far as t he act ual resolut ion is concerned, but rat her for t he level of logic/ visual correlat ion t hat languages born for calculat ion and at the most for statistic graphs allow to achieve. For t his reason, but also considering t he developm ent of t hese t ools in perspect ive, Out line s R&D t eam put a great deal of effort and work into developing and designing: V.I.P.

Ve ct or I m ple m e nt a t ion Pr ot ocol

The first software dedicated to a determinate product developed com plet ely wit h a cut t ing edge program m ing language using powerful Open GL graphic libraries. List ing all t he funct ions found in t he soft ware s Bet a Version and t hose forecast for fut ure developm ent would be a hard j ob here. so I ll j ust list a few of t he most important and include a few screen shots:

What else can be said about the Butterfly Series? We could probably list endless ot her im port ant det ails t o illust rat e it s design philosophy and t he result s obt ained, but I t hink t he cont ent s of t his white paper are more than sufficient. I t is however wort hwhile giving a m ent ion t o t he aim ing and acoust ic/ m echanical calculat ion soft ware supplied with the system. Everybody agrees t hat current requirem ent s as far as perform ance and sound qualit y of a sound reinforcement systems are concerned have increased logarit hm ically com pared t o t hose of j ust t en years ago, when t hey would have seem ed unat t ainable. Mat erial t echnology, new ideas and ( why not ?) old ideas t hat have been updat ed t o m at ch present - day const ruct ion possibilit ies, have enabled t his j um p in quality and performance. There hasn t unfort unat ely also been a sim ilar j um p in perform ance in t he behaviour of t hose in charge of audio syst em s, whet her t hey re t he sound engineers who use them or those in charge of rigging and flying. When t his rift occurs and isn t solved, it leads t o m ediocre or even pit iful result s regarding t he sole aim for which a sound reinforcem ent syst em should be used:

Creat ion, set t ing and m anual/ aut om at ic aim ing of eight vert ical line arrays sim ult aneously, wit h t wo different t ypes of Hi- Pack or Low- Pack enclosures or a third type which is a combination of the two.

Ensuring audiences the maximum sound quality t ha t t he e nvir onm e nt a l condit ions a llow , w it hout ove r look ing t he a chie ve m e nt of a n adequate sound level. To avoid one of these environmental conditions being left t o chance and subj ect ed t o m ist akes or lack of experience, often the aspects with the greatest effect on result s, m anufact urers of sophist icat ed syst em s which are t herefore difficult t o set , such as vert ical line arrays, have all developed so- called t ools which, by m eans of relat ively use- friendly soft ware dedicat ed t o a specific product , guides t he person in charge of inst alling t he syst em t hrough t he correct procedure, from t he point of view of aim ing, m echanical aspect s and problem s which occur for

Creat ion and free posit ioning of eight different simultaneous list ening areas on which t he arrays creat ed are t o be aim ed. The cross- sect ion and designed listening area can be seen simultaneously.

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 16

Tha t s a ll! I hope I ve m anaged t o give a sum m ary t hat suit ably reflect s and rewards t he recent years hard work carried out wit h great ent husiasm and det erm inat ion by Out line s R&D t eam . January 2003, BRESCIA, ITALY

Keying in dim ension param et ers of t he m iddle sect ion of t he surface at which each individual element of an array or several arrays installed has to be aimed.

This docum ent s cont ent s are subj ect t o copyright law. Reproduct ion, even part ial, is forbidden wit hout the explicit authorization of the author. All t he brands and product s m ent ioned as exam ples of t he st at e of t he art are t he propert y of t heir respective owners. The charact erist ics of t he product s m ent ioned and t he perform ance report ed in t he t ext were t aken from t he original docum ent at ion published by t he manufacturers. Information on people m ent ioned was t aken from sources available for consultation by the public.

Re fe r e nce s a nd t e chnica l bibliogr a phy quot e d in the text 1)

2) 3)

A graph is enclosed with each Array supplied, with all t he param et ers for flying according t o t he lim it s set by international norms on suspended load safety.

4)

5)

6) 7)

8)

Am ong m any acoust ic param et ers represent ed in report s of various t ypes, it s int erest ing t o see t he display, in all t he posit ions of t he plane int ercept ed by t he aim ing axis of an Array elem ent , of t he spl wit h an oct ave bargraph t aking int o considerat ion t he cont ribut ion of all t he array elem ent s at t hat point.

9)

Dr. Christian Heil CEO of L- ACOUSTICS Parc de la Fontaine de Jouvence 91462 MARCOUSSIS FRANCE Duran Audio, Koxkampseweg 10, 5301 KK Zaltbommel, The Netherlands. James F. Novak, A Column Loudspeaker with Controlled Coverage Angle. Preprint 260; Convention 14; October 1962 Sound Fields Radiated by Multiple Sound Sources Arrays Heil, Christian; Urban, Marcel AES Preprint 3269; Convention 92; March 1992 Wavefront Sculpture Technology, MARCEL URBAN, CHRISTIAN HEIL, PAUL BAUMAN AES Convention Paper 5488, 111th Convention, New York, 2001. Acoustical Engineering, Harry F. Olson D. Van Nostrand Company, Inc., 1957. Acoustics, Leo L. Beranek, McGraw- Hill Book Company, Inc. 1954. Heil Christian, US Patent N° 5,163,167 Sound Wave Guide Eric Vincenot is CEO and designer with NEXO SA 154 allée des Erables ZAC de Paris Nord II B.P. 50107 F- 95950 Roissy Cedex Francois Deffarges is a collaborator and coinvent or of t he Sound reproducing device wit h acoust ic wave guide described in t he patent application mentioned. Design of a Loudspeaker Syst em wit h a Low- Frequency Cardiodlike Radiat ion Pattern, Boone, Marinus M., Ouwelt j es, Okke, JAES Volum e 45 Num ber 9, September 1997

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 17

January 2003, Brescia, Italy IMPORTANT: Outline Butterfly m a y t h e r e for e diffe r fr om t h e de scr ipt ion s foun d in t h e se pa ge s, bu t spe cifica t ion s a n d features w ill a lw a ys be better than those indicated here. Please visit www.outline.it

Outline - via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy - tel. +39-030.358.1351 fax +39-030.358.0431 - www.outline.it - [email protected] - page 18