Personal sound masking system
View Patent ↗A sound masking system for a multi-occupant work area includes a masking signal generator generating incoherent masking sound signals loudspeaker modules interconnected in a daisy-chain fashion, with each loudspeaker module receiving the masking sound signals on input connections and transmitting them to a successive loudspeaker module on output connections. The connections on which the masking sound signals appear in each loudspeaker are shifted by the inter-loudspeaker connections, such that successive loudspeakers automatically emit different masking sound signals for improved diffuseness in the overall masking sound in the work area. Each loudspeaker module has one jack having the input connections and another jack having the output connections, and each jack receives a detachable cable such as telephone cable to connect adjacent loudspeaker modules. The masking sound signals are shifted by a cross connection network between the two jacks in each loudspeaker module.
1. A sound masking system, comprising:
a masking signal generator operative to generate a plurality of incoherent masking sound signals, the masking sound signals having spectra tailored to achieve a desired masking sound spectrum when the masking sound signals are emitted by loudspeakers in a multi-occupant workspace; and
a plurality of loudspeaker modules, the loudspeaker modules and masking signal generator being interconnected in a daisy-chain fashion such that the masking sound signals are received by each loudspeaker module on respective input connections and transmitted to an adjacent loudspeaker on respective output connections, each loudspeaker module including a loudspeaker connected to a predetermined one of the input connections, the interconnection between each pair of adjacent loudspeaker modules being operative to shift the input connections on which the respective masking sound signals appear such that successive loudspeakers emit different ones of the masking sound signals.
2. A sound masking system according to claim 1 , wherein each loudspeaker module includes an internal connection network between the input connections and the output connections, and the connections between each pair of adjacent loudspeaker modules includes the internal connection network of one of the loudspeaker modules and an external cable extending between the two loudspeaker modules, the external cable for each adjacent pair of loudspeaker modules being operative to transfer the masking sound signals between the two loudspeaker modules without shifting the connections on which the masking sound signals appear, and the internal connection network of each loudspeaker module being operative to performing the shifting of the masking sound signals as they propagate from the input connections to the output connections.
3. A sound masking system according to claim 1 , wherein each loudspeaker module includes two jacks, one jack including the input connections and receiving a first detachable cable connecting the loudspeaker module to the preceding loudspeaker module, the other jack including the output connections and receiving a second detachable cable connecting the loudspeaker module to the succeeding loudspeaker module.
4. A sound masking system according to claim 3 , wherein each detachable cable is operative to transfer the masking sound signals between two successive loudspeaker modules without shifting the connections on which the masking sound signals appear, and wherein each loudspeaker module includes an internal connection network between the first and second jacks operative to performing the shifting of the masking sound signals as they propagate from the input connections to the output connections.
5. A sound masking system according to claim 3 , wherein the number of masking sound signals is two.
6. A sound masking system according to claim 1 , wherein the number of masking sound signals is two.
7. A sound masking system according to claim 1 , wherein the plurality of daisy-chained loudspeaker modules is a first daisy chain of loudspeaker modules connected to a first set of output connections of the masking signal generator, and further comprising a second daisy chain of loudspeaker modules connected to a second set of output connections of the masking signal generator.
8. A sound masking system according to claim 7 , wherein the masking sound signals appearing on the first set of output connections of the masking signal generator are the same as the masking sound signals appearing on the second set of output connections of the masking signal generator.
9. A sound masking system according to claim 7 , wherein the masking signal generator includes two jacks, one jack including the first set of output connections and the other jack including the second set of output connections.
10. A sound masking system according to claim 7 , wherein each loudspeaker module of each daisy chain is attached to the upper part of a corresponding one of a plurality of rigid vertical members disposed in the multi-occupant workspace, and wherein the connections between each pair of successive loudspeaker modules in each daisy chain are carried by a respective cable extending between the corresponding pair of vertical members.
11. A sound masking system according to claim 10 , wherein the rigid vertical members are conduits and each cable extends within a conduit from the attached loudspeaker to a cable egress point above the loudspeaker.
12. A sound masking system according to claim 11 , wherein the cable egress point is an opening at the upper end of the conduit.
13. A sound masking system according to claim 10 , wherein each cable includes a horizontal portion disposed above a ceiling over the multi-occupant workspace.
14. A sound masking system according to claim 10 , further comprising rigid horizontal members each extending between a corresponding pair of the vertical members, and wherein each cable includes a horizontal portion extending along the outside of the corresponding horizontal member.
15. A sound masking system according to claim 1 , wherein each loudspeaker module of each daisy chain is attached to the upper part of a corresponding one of a plurality of rigid vertical members disposed in the multi-occupant workspace, and wherein the connections between each pair of successive loudspeaker modules in each daisy chain are carried by a respective cable extending between the corresponding pair of vertical members.
16. A sound masking system according to claim 15 , wherein the rigid vertical members are conduits and each cable extends within a conduit from the attached loudspeaker to a cable egress point above the loudspeaker.
17. A sound masking system according to claim 16 , wherein the cable egress point is an opening at the upper end of the conduit.
18. A sound masking system according to claim 15 , wherein each cable includes a horizontal portion disposed above a ceiling over the multi-occupant workspace.
19. A sound masking system according to claim 15 , further comprising rigid horizontal members each extending between a corresponding pair of the vertical members, and wherein each cable includes a horizontal portion extending along the outside of the corresponding horizontal member.