GB2310969A - Loudspeaker cabinet has angled S-shaped sound channel - Google Patents

Description

BASS SOUND PROJECTION SYSTEM.

The invention relates to a bass sound projection system.

A bass projection system is known which comprises an 'S' shaped sound channel within a cabinet and a speaker that is directed into and along the direction of the sound channel.

The above system has the disadvantage that the speaker diameter must fit between a side of the cabinet and a middle portion of the 'S' shaped channel.

Therefore the size of the speaker is limited.

According to the present invention there is provided a bass sound projection system comprising: a sound channel having a first portion for sound input and diverging to an open end for sound output; and a speaker having an axis and positioned directly adjacent said first portion with said axis substantially transverse the first portion.

In a preferred embodiment the above arrangement allows a 20% increase in the speaker diameter together with reduced cabinet height compared to a prior art system.

Preferably the first portion is angled relative to the side of the cabinet so that the speaker is accommodated in a corner thereof.

Advantageously the diameter of said speaker is of order of the length of the first portion.

Preferably said sound channel comprises a first U bend connecting a second portion of said sound channel to said first portion.

More preferably said sound channel further comprises a second U bend connecting a third portion at said open end of said sound channel with said second portion whereby said sound channel is substantially 'S' shaped.

A said portion may be separated from another said portion by a common partition.

According to a second aspect of the invention there is provided a bass sound projection system comprising: a cabinet; an 'S' bend sound channel having a first portion for sound input in one arm of the 'S' and an open output portion in the other arm of the 'S', said sound channel being housed in said cabinet; and a speaker having an axis for providing the sound for input into said first portion wherein said axis of the speaker is substantially transverse the direction of the first portion of said sound channel.

Preferably the input portion is angled with- respect to a cabinet wall, whereby the speaker is disposed in a corner of the cabinet.

Preferably the first portion of the channel is separated from a portion thereof forming the middle of the S by a common portion.

The output portion of the channel may be separated from a portion forming the middle of the S by a common partition.

An embodiment of the invention is described, by way of example only, with reference to the accompanying Figures in which: Figure 1 is a bass projection system of the prior art; Figure 2 is a sectioned side view of a bass projection system according to the invention; Figure 3 is a view on line 3-3 of Figure 2 of a baffle used in the system; Figure 4 is a front view of the system; and Figure 5 is a plan view of the system.

Figure 1 shows a bass projection system of the prior art comprising an 'S' shaped sound channel 6 within a cabinet 7 and a speaker 8 with its axis aligned along the sound-preparation direction of the input portion of the sound channel.

The speaker is positioned in a trapezoidal-section enclosure 9 occupying a significant volume of the cabinet.

Referring to Figure 2 there is shown a side cross section of a bass projection system 10 comprising a speaker 11 mounted in a cabinet 12. The cabinet comprises bottom and top walls 14A & 14B, a rear wall 16, and side walls (not shown). The forward part of the speaker 11 is open and forms the open end 20 of a sound channel 22 enclosed within the cabinet 12.

The sound channel 22 diverges from a sound input end 24 to its open end 20 and is substantially 'S' shaped in configuration. The sound channel 22 comprises: a first portion 26 at the input sound end 24 defined by a first partition 28 and a second partition 29 (baffle 29) and having an end closed by a third partition 30; a first bend portion 32 defined by the tip of the first partition 28 and a fourth partition 34; a second portion 36 defined by the first partition 28 and a fifth partition 38; a second bend portion 40 defined by the tip of the fifth partition 38 and the rear wall 16 of the cabinet 12; and a third portion 42 leading to the open end 20 defined by the fifth partition 38 and the bottom wall 14A of the cabinet 12.

The speaker 11 has an axis 44 and is positioned against the baffle with the axis 44 substantially transverse the direction of the first portion 26 of the sound channel 22. The position of the speaker 11 on the baffle 29 is shown in Figure 3 by a circle 46 and the baffle 29 comprises an opening 48 to allow sound to propagate from the speaker 11 into the sound channel 22. The speaker 11 is attached to the baffle 29 typically by bolts 47 around the periphery of the speaker 11. The distance between the opening 48 and the first partition 28 is in this embodiment 11 Omm, and the cross-sectional area of the opening 48 is approximately equal to that of the first portion 26 at its input end 24. This assists in efficient transfer of acoustic energy from the speaker to the sound channel.The baffle 29 is angled (here at 64" with respect to the rear wall of the cabinet 12) thereby creating a space to accommodate the speaker 11 compactly across the corner of the cabinet. This arrangement allows a larger speaker in a cabinet of reduced height. For example, an 450mm (18 inch) diameter speaker may be accommodated in a cabinet 1030mm high. The prior art system of Figure 1 has a 380mm (15 inch) diameter speaker in a cabinet 1135mm high.

The baffle 29 is constructed from 24mm ply wood whereas the other partitions and cabinet are constructed from 18mm ply wood.

Corner fillets 50A,B,C are positioned at the corners of the sound channel 22 so that the cross-sectional area of the sound channel increases substantially evenly along its length.

As shown in Figures 2 and 4 braces 52A,B are positioned in the third portion 42 of the sound channel having typical angles to the side of the cabinet of 30 and 15 respectively. These braces stiffen the sides of the cabinet to avoid undesirable resonance within the working frequency range of the system.

As shown in Figure 5 the top portion comprises two recesses 54A,B for the location of handles (not shown) to be used for carrying the system. Similar recesses (not shown) are provided in the bottom of the cabinet. A vertical brace 56 supports the lower part of the fifth partition 38. Grill supports 58 permit a curved decorative grill to be fixed across the front of the cabinet. An aperture 60 in the rear wall of the cabinet permits the instailation of a wiring connector panel for the speaker.

Each feature disclosed in the specification (which term includes the claims) and/or shown in the drawings may be incorporated in the invention independently of other disclosed and/or illustrated features.

SUMMARY A bass sound projection system has an S-shaped channel. The input portion of the channel is angled downwards to permit the speaker to be housed at an angle across the corner of the cabinet. The input and middle and the middle and output portions of the S-shaped channel share respective common partitions.

References 10 bass projection system 11 speaker 12 cabinet 14 bottom and top walls 16 rear wall 20 open end 22 sound channel 24 input end 26 first portion 28 first partition 29 second partition (or baffle) 30 third partition 32 first bend portion 34 fourth partition 36 second portion 38 fifth partition 40 second bend portion 42 third portion 44 axis of the speaker 46 position of speaker on baffle 29 47 speaker fixing bolts 48 opening 50 A,B,C corner fillets 52 A,B braces 54 A,B recesses 56 Brace 58 grill supports 60 aperture for connector panel

Claims (10)

1. CLAIMS 1. A bass sound projection system comprising: a sound channel having a first portion for sound input and diverging to an open end for sound output; and a speaker having an axis and positioned directly adjacent said first portion with said axis substantially transverse the first portion.
2. 2. A sound system as claimed in Claim 1 wherein the first portion is angled relative to a wall of the cabinet, whereby the speaker is disposed in a corner thereof.
3. 3. A sound system as claimed in Claim 1 or 2 wherein said sound channel comprises a first U bend connecting a second portion of said sound channel to said first portion.
4. 4. A sound system as claimed in Claim 3 wherein said sound channel further comprises a second U bend connecting a third portion at said open end of said sound channel with said second portion whereby said sound channel is substantially 'S' shaped.
5. 5. A sound system as claimed in Claim 3 or Claim 4 wherein a said portion is separated from another said portion by a common partition.
6. 6. A bass sound projection system comprising: a cabinet; an 'S' bend sound channel having a first portion for sound input in one arm of the 'S' and an open output portion in the other arm of the 'S', said sound channel being housed in said cabinet; and a speaker having an axis for providing the sound for input into said first portion wherein said axis of the speaker is substantially transverse the direction of the first portion of said sound channel.
7. 7. A sound system as claimed in Claim 6 wherein the input portion is angled with respect to a cabinet wall, whereby the speaker is disposed in a corner of the cabinet.
8. 8. A sound system as claimed in Claim 6 or 7 within the first portion of the channel is separated from a portion forming the middle of the 'S' by a common partition.
9. 9. A sound system as claimed in Claim 7 or 8 wherein the output portion of the channel is separated from a portion forming the middle of the S by a common partition.
10. 10. A sound system substantially as herein described with reference to Figures 2 to 5 of the accompanying drawings.