Technical Field:

The present invention is a line array type audio loudspeaker system capable of extreme high output capability and durability in comparison with other systems currently available at a similar cost. Other desirable characteristics included in the design are very flat frequency response, low distortion, the ability to reproduce loud transients with minimal acoustical compression, low distortion and a dispersion pattern optimized lor maximum projection in most applications. Background of the Invention:

Prior art in loudspeaker systems with extreme high output are primarily limited to systems utilizing large dynamic type horn loaded compression drivers to cover the upper frequency ranges. The drawback to this approach is that: 1. Large dynamic compression drivers are expensive, heavy and take up to much space precluding their use in multiples in a reasonable sized enclosure, thereby limiting the maximum possible output. 2. The dispersion characteristics of these units are not uniform or easily optimized for the majority of applications. 3. Large dynamic compression dnvers historically and in the current state of the art have much more irregular frequency response characteπstics then smaller tweeter type units. 4. Large dynamic compression drivers suffer from acoustic compression in the throat area limiting dynamic peak output severely. 5 These types of drivers cannot typically be mounted in such a way as to achieve phase aligned output λvith the low frequency transducers. Summary of the Invention:

The present invention provides a loudspeaker comprising a box having a longitudinal axis, a front, a back, a first side and a second side; a plurality of midrange/woofers of the cone transducer type mounted on the front of said box parallel to said longitudinal axis; and a plurality of midrange/tweeters mounted on the front of said box parallel to the longitudinal axis; an audio signal being connected to said plurality of said midrange/woofers and midrange/tweeters through an active or passive

crossover network to direct the high frequencies to the midrange/tweeters and the low frequencies to the mi range/woofers, the improvement which comprises at least one structure selected from the group consisting of a line array wherein a line array of midrange/woofers and a separate line array of midrange/tweeters is positioned in mechanical phase alignment and a line array of midrange/woofers and midrange/ tweeters arranged such that a separate line array of midrange/tweeters extends a first length and a separate line array of midrange/woofers extends a second length and the first length is in the range of 5U% to 200% of the second length, and in either configuration the positioning of the separate line arrays is such that the combined line arrays produce uniform controlled dispersion characteristics through the frequency range of both line arrays.

Brief Description of the Drawings:

FIG I is an isometric view of a line array composing midrange/woofers and midrange/tweeters of the horn or dome type. FIG 2 is a horizontal section of a an array as illustrated in FIG 1 taken lo show bolh a midrange/woofer and midrange/tweeter in cross section at their center lines.

FIG 3 is an isometric view of a line array wherein the midrange/tweeter array is recessed relative to the mounting plane of the woofer array.

FIG 4 is a horizontal section of a line array as illustrated in FIG 3 taken to show both a midrange/woofer and a midrange/tweeter in cross section at their center lines

FIG 5 is an isometric view of a line array wherein the midrange/tweeter array is placed in front of the midrange/woofer array

FIG 6 is a horizontal section of a line array as illustrated in FIG 5 taken to show both a midrange/woofer and a midrange/tweeter in cross section at their center lines FIG 6a is a detailed view of a midrange/tweeter array mounting rib as shown in FIG 6

FIG 7 is a detailed view of a midrange/tweeter mounted to a rail for placement as shown in FIG 5.

FIG 8 is an isometric view of a line array showing a grill cut away.

FIG 9 is an isometric view of an enclosure showing ports in the rear wall

Detailed Description of the Invention:

Turning to FIG 1 a loudspeaker is shown comprising a box having a longitudinal axis, a front (3), a back ( 1 ), a first side (4) and a second side (2) housing a plurality of midrange/woofers of the cone transducer type (5) mounted on the front of said parallel to said longitudinal axis, and a separate array of a plurality of midrange/tweeters of the horn, dome, or other type (6) mounted on the front of said box parallel to the longitudinal axis, such that an audio signal being connected to said plurality of said midrange/woofers and midrange/tweeters through an active or passive crossover network lo direct the high frequencies to the midrange/tweeters and the low frequencies to the midrange/woofers to produce a coherent pattern of low dispersion sound and a uniform frequency response throughout the range of both line arrays

In FIG 2 is shown a horizontal cross section of the midrange/tweeters showing the speakers are mounted in such a way that the apex of the diaphragms or acoustic sound source (7) is the same distance from the listener in the vertical field as the apex of the cones ( ) of the plurality of midrange/woofers in the vertical field (to produce mechanical phase alignment) An alternative embodiment is shown in FIGS 3 & 4, shows and alternative embodiment accomplished by mounting the plurality of midrange/tweeters on a recessed or offset panel (9) Mechanical phase alignment may be also achieved by using transducers that have the correct depth and diaphragm position with no offset (as in FIGS I and 2)

Alternatively line arrays of separate woofers and tweeters may be positioned such that an array of tweeters is placed slightly in front of an array of woofers provided that the lengths of the arrays are within 50% of each other and the speakers will couple to produce a coherent sound pattern of low dispersion without requiring a compression dπver This configuration is preferred and is the best mode currently known to the inventor

In a preferred embodiment the plurality of midrange/tweeters extend a first length and the plurality of midrange/woofers extend a second length the lengths of the piuraluy of midrange/tweeters and the plurality of midrange/woofers to be within 50% of each other In other words the first length falls in the range from 50% to 200% ol the second

length. Preferred line arrays range include from 2 to 24 midrange/woofers preferably 4 to 8; each having a diameter of from 2 to 18 inches preferably 8 to 18 inches most preferably 12 to 18 inches. Tweeters in preferred line arrays include from 3 to 32, preferably 4 to 16, more preferably 9 to 15 midrange/tweeters having a diaphragm diameter of from 0.25 to 3 inches, more preferably 1 to 3 inches, most preferably about 1 to 2 inches

In one embodiment the plurality of midrange/tweeters and the plurality of midrange/woofers are connected to a crossover network in a parallel configuration Alternatively , the plurality of midrange/tweeters and the plurality of midrange/woofers are connected to a crossover network in a series configuration In a preferred embodiment the plurality of midrange/tweeters and the plurality of midrange/woofers are connected to a crossover network in a series/parallel configuration

The term midrange/woofer means a woofer also covering the lower midrange with a frequency range of from 20 to 250hz on the low side to between 750 and 4000hz on the high side. The term midrange/tweeter means a tweeter that also covers the upper midrange and with a frequency range of from between 750hz and 4000 on the low side to between 12,000 to 20,000hz on the high side.

The plurality of midrange/tweeters and the plurality of midrange/woofers are designed so as to have a very flat frequency response characteristic w th a smooth roll off above and below their usable range This is achieved by overlapping the crossover transition occurring over a broad frequency range. Preferably the high end of the midrange/woofer range overlaps the low end of the midrange/tweeter range by 500 to 3500hz It has been found that overlapping substantially produces a very smooth crossover between the plurality of midrange/tweeters and the plurality of midrange/woofers without the complex crossover networks normally employed in high output - high performance loudspeakers

An advantage of the invention is that a line array of inexpensive nudrange/iweeiers is used instead of the customary relatively expensive large compression driver and horn common to high performance systems of today The plurality of midrange/tweeters may individually be inexpensive units but the combined

surface area of the diaphragms and throat area if horn midrange/tweeters are used is many times greater than the single or dual units of conventional systems This allows for higher output before the onset of acoustic compression and much greater dynamic headroom In the best mode configuration a plurality of inexpensive midrange/tweeters s are mounted in an on axis position directly in front of the midrange/woofers (as in FIG 5 ) This can be accomplished using wood or metal rails that do not substantially block the output of the midrange/woofers or by mounting the midrange tweeters to a front gπll Preferably the sides of the enclosure do not extend out past the midrange/woofers so as not to cause acoustic interference in the radiation of the midrange/woofers in conjunction ιo with the blockage caused by the midrange tweeters In testing it was found that the midrange/tweeters being mounted directly in front of the midrange/woofers did not cause an objectionable elk ct in acoustic performance as long as the sides of the enclosure do not extend oul substantially and cause there to be a trapped air space between the extended sides of the enclosure and the midrange/tweeters (as in FIGS 5 & 8 ) In a i s preferred embodiment ceramic or piezoelectric type midrange/tweeters are used

In FIGS 5 and 6 is seen the best mode embodiment A line array loudspeaker comprises a box (1 1 ) being defined by a first side wall ( 12) and a second side wall ( 14) attached to an end wall ( 16) (FIG 6), a front wall (18), a top panel (20) and a bottom panel (22) The top panel (20) defines a top shelf (24) extending therefrom at an angle 0 perpendicular to the front wall (18) The bottom panel (22) defines a bottom shelf (26) extending therefrom at an angle perpendicular to the front wall( 18) and parallel to the top shelf (24) (See figs 5-9)

The front wall (18) forms at least two openings, sized to receive the midrange/ woofer ( 10) described previously Each of the midrange/ woofers ( 10) defines a 5 longitudinal axis about which the midrange/ woofer is symmetnc The back wall defines an opening or port (42) as shown in Fig 1 1

FIG 6a shows a mounting means (34) is provided for mounting a plurality of mid -range/ tweeters (28) to the box ( 1 1 ) between the top shelf (24) and the bottom shelf (26) The plurality of mid-range/tweeters are aligned in a parallel, spaced apart 0 relationship to the midrange/woofers (10) The midrange/woofers being positioned

between the end wall and the plurality of mid-range/tweeters. The plurality of midrange/tweeters have a longitudinal axis (32) about which they are symmetric. The plurality of midrange/tweeters are positioned at an angle perpendicular to the longitudinal axis of the midrange/woofers, so that the longitudinal axis (32) of the plurality of midrange/tweeters is parallel to the longitudinal axis (30) of the midrange/ woofers(lθ).

The mounting means (34) comprises a cross brace (36) mounted on the front wall (1 ) and positioned perpendicular to the front wall ( 18). The cross brace (36) is designed to receive a pair of rails (38) for receiving the plurality of midrange/tweeters The ϋs can be aluminum, steel or wooden. The plurality of midrange/tweeters is boiled lo the rails (38) and is held in a parallel spaced apart relationship to the midrange/woofers The cross brace (36) further defines a depression (40) for receiving a bottom edge (52) of the midrange/woofer. A single tweeter (29) attached to the pair of rails (38) is shown in Fig 9. As shown in FIG 6, the end wall ( 16) is shorter in length than the front wall ( 1 ), thus giving the box (1 1) a cross sectional truncated V-shape. The first side wall forms an angle 54 with the end wall of eight degrees from the axis 30. A grill (44) as shown in FIG 8 is provided for covering the plurality of midrange/tweeters and the midrange/ woofers. The grill is attached to the first side wall, the mounting means, and the second side wall. An angle (56) defined by the first side wall and the grill (44) is greater than 90 degrees and an angle (58) defined by the second side wall and the grill (44) is greater than 90 degrees. The angle (60) defined by the grill and the mounting means is greater than 90 degrees.

While the preceding embodiments illustrate the improved loudspeakers that use the line array configuration to achieve a novel coupling of the individual speaker out put to achieve a coupled controlled dispersion sound pattern that is uniform throughout the speaker frequency range, those skilled in the art will be aware of many variations that may be made without departing form the spirit of the invention. The illustrative embodiments are shown to describe the invention and not as limitations. The invention is defined by the claims as set out below.