example the 900 mhz or 2 4 ghz wireless receiver transmitters provided by x 10 usa closter n j 07624 may be used in such case a receiver 27 located at the spa provides the home audio signal to the amplifier 15 which then drives the transducers 11 in operation the audio can be heard under water 29 as well as above the water 29 listeners outside the spa can also hear the audio signal but the experience is muted compared to that of the tub occupant the means of attaching an acoustic driver to the spa shell is important in order to cause the spa shell to function as a speaker cone driven by the audio transducer attached to it with a frequency range comparable to an average speaker system the attachment means is important also to the extent that it must perform in a harsh outside and perhaps wet environment without breaking down if the interface connection between the spa shell and the audio transducer breaks down by coming loose for example the function of the entire system fails besides using appropriate compatible adhesives to attach mounting blocks to the underside of the spa shell for mounting audio transducers it has been found that.