Abstract:
A system for automatically adjusting the audio level in response to spa jet pump and air blower settings in an audio system mounted in a spa or hot tub. A preferred embodiment includes a spa pump/blower sensor apparatus, and an electronic controller circuit which interfaces to the audio system and the spa pump/blower sensors.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority of Provisional application Ser. No. 60/480,049, filed on Jun. 20, 2003. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates generally to the field of electrical devices, and more particularly to an apparatus for compensating for pump noise in an integrated spa audio system.  
         BACKGROUND OF THE INVENTION  
         [0003]    In a typical spa or hot tub, the water circulating pumps and air blowers create a significant amount of noise when they are activated. This noise level varies as a function of how many, and which of the available pumps/blowers, are operating at any one time. It is becoming increasingly popular to outfit the spa unit with an integrated audio system. This system typically consists of two or more loudspeakers mounted at or above the plane of the water, and an audio head unit to provide source material and amplification for the audio system. If the spa occupant is listening to a program source at a relatively low level, and one or more pumps/blowers are switched on, the perception of the loudness of the music signal is dramatically altered. In the most extreme case the music can be masked entirely. Conversely, if a desired music level is selected while the pumps/blowers are active, after shutting off the pumps/blowers, the music will seem much too loud.  
           [0004]    Historically there has been no way to automatically compensate for this noise masking effect. The operator would have to manually adjust the audio level in order to compensate for the masking effect of the pump noise.  
           [0005]    A further challenge lies in the detection of spa pump operation. Most spa controllers do not provide any easily accessible logic pins for an external circuit to monitor pump status. Pump motors are typically high voltage and high current devices. There are very strict regulations relating to electrical devices in the spa environment, especially devices which are in contact with high voltage circuits.  
           [0006]    Audio system head units that are commonly used in spa audio systems lack a means for adjusting the audio signal level by a remote circuit. This lack of interface prevents the conventional components from being able to be used in conjunction with a noise compensation circuit.  
         SUMMARY OF THE INVENTION  
         [0007]    The primary object of the invention is to provide a means for automatically adjusting the sound level of an audio system in spa and hot tub applications.  
           [0008]    Another object of the invention is to be able to detect the spa pump/blower status without direct electrical connection to the pump wires or controlling electronics.  
           [0009]    Other objects and advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.  
           [0010]    This invention features an apparatus where the operation of the various pumps and blowers is sensed, the average ambient noise level contributed by them is determined, the sound level of the audio system is determined, and said sound level is adjusted such that the listener perceives a consistent sound level from the audio system regardless of changing pump/blower settings.  
           [0011]    The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspect of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a block diagram of the primary components of the preferred embodiment of the system of the invention;  
         [0013]    [0013]FIG. 1A is a more detailed block diagram of the noise compensation processor of FIG. 1;  
         [0014]    [0014]FIG. 2 is a more diagram of the preferred inductive pick-up methodology of the invention;  
         [0015]    [0015]FIG. 3 is a block diagram of an alternate embodiment using a wireless interface to a conventional head unit; and  
         [0016]    [0016]FIG. 3A is a more detailed block diagram of the noise compensation processor of FIG. 3. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    Detailed descriptions of the preferred embodiments are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or manner.  
         [0018]    Turning to FIG. 1 there is shown a block diagram of the primary components relating to a preferred embodiment of the invention. Inductive pick-up sensors  5  are mounted on the various high current circuits for the pumps/blowers. Sensors  5  determine when a pump or blower circuit is passing current to the pump/blower motor. A noise compensation processor  1  is connected to audio head unit  4  via an interface bus  2 . The head unit interface bus  2  presents the noise compensation processor  1  with internal audio signals such that these signals can be monitored and modified to achieve the goals of the invention.  
         [0019]    [0019]FIG. 1A is detailed block diagram of the preferred embodiment of the noise compensation processor for the invention. Pump detection circuit  20  receives signals from pump sensors  21  and interfaces to microprocessor  19 , allowing the system to determine which, if any of the spa pump circuits are operating. The audio input signal  15  is fed to audio signal level detection circuit  18  where the average audio level is determined, and sent to microprocessor  19 . Using the pump status and signal level information, microprocessor  19  calculates a noise coefficient based on previously determined pump/blower noise data. Using algorithms and look-up tables, a gain adjustment is calculated and applied to variable gain element  17 , which sends the processed audio output  16  to the head unit. Because the audio signal is constantly monitored, the administered level adjustment is based on the actual audio level, not the volume setting. This approach has the benefit that it provides not only an overall level adjustment of the audio signal, but also provides a dynamic range compression of the audio signal. Dynamic range compression is important in noisy environments where the audio program material sound level varies greatly. This is commonly found in classical music with wide dynamics, or a movie soundtrack where a loud chase scene might be followed by quiet dialog. The process is constantly repeated in order to maintain an optimal audio signal to pump/blower noise relationship. In another embodiment, audio frequency equalization may also be applied to the audio signal as a function of spa noise. This can have the advantage of recovering specific frequencies that the spa pump generated noise might be masking.  
         [0020]    [0020]FIG. 2 is a more detailed view of one manner of detecting pump operation. Spa controller board  7  contains the logic and switching relays for the pumps and blowers. Inductive pick-up clips  9  are clipped to each of the noise producing pump/blower winding circuits  8 . Some pumps or blowers may have multiple speeds, for example separate low and high-speed circuits. In this case, by employing sensors on each of the drive circuits, the speed of operation can also be determined, and the audio output level adjusted accordingly. Wiring harness  10  carries the signals back to the noise compensation processor for filtering and detection.  
         [0021]    [0021]FIG. 3 shows an alternate embodiment where audio head unit  11  is of conventional design, equipped with a wireless receiver  12 . In this embodiment, noise compensation processor  14  is configured to output a data stream compatible with the audio head unit&#39;s wireless control input. The signal is sent to the audio head unit via wireless transmitter  13 .  
         [0022]    [0022]FIG. 3A is a more detailed block diagram of this alternate embodiment. Pump and audio level detection are calculated in the same manner as described for FIG. 1A. In this case audio input  22  would connect directly to a loudspeaker output on the head unit. After calculating the gain adjustment, microprocessor  25  generates a volume control code and sends a bit stream to wireless transmitter  23 , which transmits the signal to the audio head unit, thereby adjusting the audio level. Means for transmission is most commonly through Infra-red (IR) signal, although other mechanisms could be used, including RF, and serial data through a wired connection.  
         [0023]    While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.