Frequency attenuation compensated pneumatic headphone and liquid tube audio system for medical use

Abstract

A confined system of sound transmission from a frequency attenuation compensated source through plastic pneumatic tubes in series with liquid tubes of considerable length, transmitting audio to and through pneumatic headphones to the ear canals of the user. It is an audio system suitable for use in Nuclear Magnetic Resonance scanning environments and for use in CAT scan environments. The system includes a stereo program source playing into a stereo frequency compensation amplifier driving right and left loudspeaker pneumatic drivers feeding audio to and through long liquid tubes in series with pneumatic tubes extended to left and right earphones of plastic headphones worn by a patient in a scan room environment. The tubes that extend from the electronic audio system equipment outside the scan room through scan room walls to the patient headphones and the headphones themselves are made of plastic or other non-magnetic materials causing no interference with the scanning signals and are not visible on scan pictures produced.

I claim: 
     
       1. A frequency attenuation compensated pneumatic headphone and acoustic tube audio system comprising: pneumatic tube driver means; acoustic plastic tube means transparent to scanning fields such as a Nuclear Magnetic Resonance field and in a length range of approximately ten to fifty feet; plastic material pneumatic headphones for a user that are transparent to scanning signals so as to not cause interference with scanning signals; pneumatic tube driver means for driving audio signals through said acoustic plastic tube means and said pneumatic headphones to the ears of a user; program signal source means; a frequency response compensation amplifier connected to the output of said program signal source means that with progressively higher frequencies boosts the higher frequencies to compensate for the increasing attenuation of progressively higher frequencies as audio is passed through said acoustic tube means; circuit means interconnecting said compensation amplifier and said pneumatic tube driver means; including pneumatic driver amplifier means interconnecting said compensation amplifier and said pneumatic tube driver means; wherein said program signal source means is a stereo signal source; said compensation amplifier is a stereo signal two channel amplifier; monitor speaker means is connected directly to said program signal source means; said pneumatic driver amplifier means includes a stereo control amplifier and left and right pneumatic driver amplifiers; and wherein said compensation amplifier includes settable resistance valve means for adjusting higher frequency boost compensation for different length acoustic plastic tube means of substantially matched pair lengths used in different installations. 
     
     
       2. The frequency attenuation compensation pneumatic headphone and tube audio system of claim 1, wherein a microphone and microphone amplifier are included with the audio system also including switch means in the input circuit path to said compensation amplifier connected to the output of said microphone amplifier and connected to the output of said program signal source means and controllable for switching between said program signal source means and said microphone amplifier. 
     
     
       3. The frequency attenuation compensation pneumatic headphone and tube audio system of claim 2, wherein said switches means is a relay switch connected to an operator operated power switch. 
     
     
       4. The frequency attenuation compensation pneumatic headphone and tube audio system of claim 1, wherein said settable resistance value means is a potentiometer with an adjustably settable tap. 
     
     
       5. The frequency attenuation compensation pneumatic headphone and tube audio system of claim 1, wherein pneumatic plastic tube means is included in said acoustic plastic tube means; and said compensation amplifier has RC input network means that sets low frequency roll-off such that headphone response is essentially flat with shorter lengths of pneumatic tubing in the ten foot to twenty foot range. 
     
     
       6. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 1, wherein pneumatic plastic tube means is included in said acoustic plastic tube means; and said pneumatic driver means includes a box means enclosing a loudspeaker means with cavity means between the loudspeaker and the front end wall of the box; a hole in said end wall in open communication with said cavity means; and with a tubing end of said pneumatic plastic tube means received in said hole in said end wall for importing into and through the tubing audio signalling generated in said loudspeaker. 
     
     
       7. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 6, wherein said box means comprises two used as said pneumatic driver means one a left pneumatic driver and the other a right pneumatic driver connected to left and right pneumatic plastic tubes of approximately the same length that in turn are extended to and feed left and right stereo signals to left and right earphones, respectively, of said plastic material pneumatic headphones. 
     
     
       8. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 1, wherein said program signal source is a left and right channel stereo program signal source; said compensation amplifier is a two channel stereo amplifier; and said pneumatic tube driver means is a two speaker boxes each enclosing a loud speaker and feeding audio signals to a pneumatic plastic tube portion of said acoustic plastic tube means connected to each; and with the two tubes of approximately the same length connected to left and right earphones of a headset. 
     
     
       9. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 8, wherein said circuit means includes pneumatic driver stereo amplifier means interconnecting said two channel stereo amplifier and said two speaker boxes comprising said pneumatic driver means. 
     
     
       10. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 9, wherein said compensation amplifier has an RC input network means in each of two input channels that set low frequency roll-off such that headphone response is essentially flat through shorter lengths of said pneumatic tube portion in the ten foot to twenty foot range. 
     
     
       11. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 10, wherein each of said boxes encloses a loudspeaker on a cavity wall with a cavity between the loudspeaker and a front wall of the box; a hole in said front wall in open communication with said cavity; a resonant chamber behind the loudspeaker; and with a tubing end of said pneumatic plastic tube portion received in said hole in said front wall for imparting into and through the tubing audio signalling generated in said loudspeaker. 
     
     
       12. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 11, wherein a microphone and microphone amplifier is included with the audio system; switch means is included in the left and right channel input circuits paths to said stereo compensation amplifier; and with said switch means connected to the output of said microphone amplifier and connected to the left and right channel outputs of said stereo program signal source means; and wherein said switch means is a multi-contact relay switch connected to an operator controlled power on/off switch. 
     
     
       13. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 1, wherein said acoustic tubing includes both pneumatic plastic tubing and liquid plastic tubing. 
     
     
       14. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 13, wherein the pneumatic plastic tubing is included in a left channel and in a right channel of said acoustic tubing. 
     
     
       15. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 14, wherein the total length of pneumatic plastic tubing is substantially equal between said left and right channels of acoustic tubing. 
     
     
       16. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 15, wherein most of the acoustic tubing length in both said left and right channels is liquid plastic tubing. 
     
     
       17. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 16, wherein said liquid plastic tubing is made up in sections with a liquid retaining diaphragm in a pneumatic to liquid acoustic transducer at each end of each of said liquid plastic tubing sections. 
     
     
       18. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 17, wherein pneumatic tube lengths interconnect said pneumatic tube driver means and liquid plastic tubing sections in both said left and right channels; and pneumatic tube headphone section lengths interconnect said liquid plastic tubing sections and said pneumatic headphones. 
     
     
       19. The frequency attenuation compensated pneumatic headphone and tube audio system of claim 17, wherein a pneumatic to liquid acoustic transducer of each of said liquid plastic tubing sections is directly connected to said pneumatic tube driver means. .Iadd. 
     
     
       20.  A sound system for conducting audio signals to a person in an electromagnetic scanning signal field, comprising: program signal source means disposed outside of said electromagnetic scanning signal field and including means for generating sound signals,   audio signal generator means for generating audio signals representative of the signals from the program signal source means,   headphone means for a person disposed in said electromagnetic scanning signal field, said headphone means being substantially transparent to the scanning signals of the scanning signal field,   acoustic tube means for conducting the audio signals from a position outside of said scanning field to the headphone means disposed in said scanning signal field, said acoustic tube means having a length of approximately between 10 to 50 feet long so as to accommodate spacing of the program signal source means outside of the scanning field while the headphone means are in the scanning field, said acoustic tube means being substantially transparent to the scanning signals of the scanning signal field,   and frequency response compensation amplifier means interposed between the program signal source means and the audio signal generator means for compensating for different frequencies of the audio signal as it is conducted through the acoustic tube means to the headphone means. .Iaddend. .Iadd.   
     
     
       21.  A system according to claim 20, wherein said electromagnetic scanning field is in a scanning room which accommodates a person being diagnosed by the scanning signal field, and wherein the acoustic tube means extends from outside the scanning room to the headphone means in the scanning room. .Iaddend. .Iadd.22. A system according to claim 21, wherein said acoustic tube means comprises pneumatic tube means extending from outside the scanning room to the headphone means in the scanning room. .Iaddend. .Iadd.23. A system according to claim 22, wherein said audio signal generator means comprises speaker means opening to the pneumatic tube means. .Iaddend. .Iadd.24. A system according to claim 22, wherein said pneumatic tube means are made of plastic material. .Iaddend. .Iadd.25. A system according to claim 24, wherein said headphone means are made of plastic material. .Iaddend. .Iadd.26. A system according to claim 20, wherein said acoustic tube means includes a pair of substantially matched pair length pneumatic tubes. .Iaddend. .Iadd.27. A system according to claim 20, wherein said compensation amplifier means includes settable resistance value means for adjusting higher frequency boost compensation for longer length acoustic tube means. .Iaddend. .Iadd.28. A system according to claim 20, further comprising monitor speaker means disposed outside the scanning field for monitoring the source signals, said monitor speaker means being connected to the program signal source means in parallel with the frequency response compensation amplifier means. .Iaddend. .Iadd.29. A system according to claim 20, further comprising microphone means for accommodating selective operator voice communication to the headphone means via the acoustic tube means. .Iaddend. .Iadd.30. A system according to claim 29, wherein said microphone means includes microphones output signal means connected to the frequency response compensation amplifier means. .Iaddend. .Iadd.31. A system according to claim 28, further comprising microphone means for accommodating selective operator voice communication to the headphone means via the acoustic tube means. .Iaddend. .Iadd.32. A system according to claim 28, wherein said electromagnetic scanning field is in a scanning room which accommodates a person being diagnosed by the scanning signal field,   wherein said monitor speaker means is disposed outside the scanning room,   and wherein the acoustic tube means extends from outside the scanning room to the headphone means in the scanning room. .Iaddend. .Iadd.33. A system according to claim 32, wherein said acoustic tube means comprises pneumatic tube means extending from outside the scanning room to the   
     
     
        headphone means in the scanning room. .Iaddend. .Iadd.34.  A system according to claim 33, wherein said audio signal generator means comprises speaker means opening to the pneumatic tube means. .Iaddend. .Iadd.35. A system according to claim 34, further comprising microphone means for accommodating selective operator voice communication to the headphone means via the acoustic tube means. .Iaddend. .Iadd.36. A system according to claim 29, further comprising operator controllable switch means for accommodating selective actuation of the microphone means and the source signal generator means. .Iaddend. .Iadd.37. A system according to claim 36, wherein said switch means includes means for automatically simultaneously deactivating the source signal generator means and activating the microphone means. .Iaddend. .Iadd.38. A system according to claim 20, wherein said source signals are stereo signals and said audio signals are audio stereo signals, and wherein said acoustic tube means includes a pair of tubes for transmitting respective different components of the audio stereo signals to different ear pieces of the headphone means. .Iaddend. .Iadd.39. A system according to claim 20, wherein said frequency response compensation amplifier means includes means for effectively boosting higher frequency source signals to compensate for attenuation of progressively higher frequencies of the audio signals conducted through the acoustic tube means to the headphone means. 
     
     
        .Iaddend. .Iadd.40.  A method for conducting audio signals to a person in an electromagnetic scanning signal field, comprising: disposing program signal source means outside of said electromagnetic scanning signal and generating sound signals therewith,   providing audio signal generator means for generating audio signals representative of the signals from the program signal source means,   providing headphone means for a person disposed in said electromagnetic scanning signal field, said headphone means being substantially transparent to the scanning signals of the scanning signal field,   providing acoustic tube means for conducting the audio signals from a position outside of said scanning field to the headphone means disposed in said scanning signal field, said acoustic tube means having a length of approximately between 10 to 50 feet long so as to accommodate spacing of the program signal source means outside of the scanning field while the headphone means are in the scanning field, said acoustic tube means being substantially transparent to the scanning signals of the scanning signal field,   providing frequency response compensation amplifier means interposed between the program signal source means and the audio signal generator means for compensating for different frequencies of the audio signal as it is conducted through the acoustic tube means to the headphone means, and   activating said electromagnetic scanning field with a person disposed therein while simultaneously supplying audio signals to said headphone means via the audio signal generating means and the acoustic tube means whereby said audio signals are supplied without interfering with said electronic scanning signal field. .Iaddend. .Iadd.41. A method according to claim 40, wherein said electromagnetic scanning field is in a scanning room which accommodates a person being diagnosed by the scanning signal field,   and wherein the acoustic tube means extends from outside the scanning room to the headphone means in the scanning room. .Iaddend. .Iadd.42. A method according to claim 41, wherein said acoustic tube means comprises pneumatic tube means extending from outside the scanning room to the headphone means in the scanning room. .Iaddend. .Iadd.43. A method according to claim 42, wherein said audio signal generator means comprises speaker means opening to the pneumatic tube means. .Iaddend. .Iadd.44. A method according to claim 40, wherein said compensation amplifier means includes settable resistance value means for adjusting higher frequency boost compensation for longer length acoustic tube means. .Iaddend. .Iadd.45. A method according to claim 40, further comprising disposing monitor speaker means outside the scanning field for monitoring the source signals, said monitor speaker means being connected to the program signal source means in parallel with the frequency response compensation amplifier means. .Iaddend. .Iadd.46. A method according to claim 40, further comprising providing microphone means for accommodating selective operator voice communication to the headphone means via the acoustic tube means. .Iaddend. .Iadd.47. A method according to claim 29, wherein said microphone means includes output signal means connected to the frequency response compensation amplifier means. .Iaddend. .Iadd.48. A method according to claim 28, further comprising providing microphone means for accommodating selective operator voice communication to the headphone means via the acoustic tube means. .Iaddend.