Recording Microwave Hearing Effects: Literature Review and Case Report of an Affiant to Recording Remote Harassment


John J. McMurtrey, M. S., Copyright 2006, 2008 Jul 20


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            Literature pertaining to the conditions by which microwaves produce sound via the thermoelastic effect and recording the effect is reviewed with comparison to microphone components.  A case report of an affiant to recording remote harassment is presented.  Actual words understood as transmitted by the affiant could have been recorded as distorted sound.


Introduction and Literature Review


The accepted microwave hearing mechanism is by thermoelastic expansion resulting in acoustic perception. [1] [2]  The rapid heating of a surface sets up stress waves of sound within a material, and this is more pronounced for constrained surfaces. [3] [4] [5]  Glass containers are considered a constraining surface, and the ability to record microwave hearing sound is described utilizing hydrophones (a liquid immersible microphone) in water or salt solutions. [6]  Such effects are detected by implanted hydrophone within the heads of rats, guinea pigs, or cats [7] [8] as well as from model equivalents of muscle [9] and brain. [10] 

In appropriate materials and situations the thermoacoustic vibrations are strong enough to be air conducted with reports of such sound production.  The ability to hear microwave pulses impinging on tin foil held next to the ear is described. [11]  Audible sounds were observed during an interferrometric study in certain lossy dielectric materials. [12]  Two patents discuss the ability of the radio frequency (microwave) hearing effect to produce sound in spheres of material with appropriate radio frequency response,[13] [14] and mathematical prediction of such effects compared to experimental results in dielectric spheres is available. [15]  An article on recording simple microwave hearing effects by microphone describes sound production in carbon impregnated polyurethane. [16]  This microwave absorber produced sound from pieces as small as 4 mm2 by 2 mm thick.  Tin foil was also tested as a microwave sound transducer with sound induced by microwave pulses in crumpled foil, though whole sheets did not produce sound. 

One microphone design is known responsive to the thermoacoustic effect, and several other microphone designs involve elements that are very similar to conditions producing sound in thermoacoustic or microwave hearing literature.  Since rapid transient heating of a very small surface depth is the thermoacoustic mechanism, the effect is more related to the energy deposited, materials, and conditions than the electromagnetic energy source.  Sound is produced by lasers from thin metal films, particularly as deposited on a constraining surface. 5  Thermoacoustic sound is produced by lasers in aluminum films, [17] and by radio frequency in gold, nickel, or titanium. 3  Condenser (or capacitor) microphones have a diaphragm that is normally made of mylar with a metallic film backing, which is usually of gold, though aluminum, nickel, or titanium have also been used. [18]  Thermoacoustic sound production from metal as simply constrained by Mylar tape is mentioned in laser experiments. 5  Condenser microphones are shown directly responsive to thermoacoustic sound production in laser experiments. [19]  The electrolet microphone is a recent design variety of the condenser microphone. [20]  Ribbon microphones utilize aluminum foil that is often corrugated, which is similar to the crumpled tin foil microwave sound production above, and a recent ribbon design variant has the aluminum on a polyester film, [21] which imposes a constraint known to enhance thermoacoustic sound production. 3  Microphones based on piezoelectric films have aluminum deposited upon the film as an electrode, [22] and piezoelectric materials from which such films are composed are acoustically responsive to microwave excitation.  [23]  One report on recording microwave hearing sound within animal heads notes free air response of a lead zirconate-titanate (a piezoelectric material) hydrophone to microwave pulses that was considered an artifact to within head sound recording. 7

Sharp and Grove were co-authors in an above citation on recording microwave hearing effects from microwave absorbing material, and also discovered a method of voice transmission to humans. 11  This voice transmission technique can pass though walls, and there is evidence of further development of such capability with references to detrimental uses as well as the existence of weapons. [24]  Substantiation for plausibility of directly recording microwave hearing harassment is indicated by:  the demonstration of condenser microphone thermoacoustic response, the indications of piezoelectric microwave effect implies piezoelectric microphone response, and the similarity in other microphone designs of elements responsive to thermoacoustic conditions.

People who consider themselves harassed by what may be microwave hearing technology have formed protest organizations around the world. [25] [26] [27] [28] [29]  One of these groups, Citizens Against Human Rights Abuse (now Mind Justice) had anecdotes of recordings that captured harassing voice transmissions.  On receiving one such recording, this organization decided to commission a study to attempt to capture voice transmission near victims who complain of such symptoms.  The study was inconclusive and not fully completed due to the terminal illness of the investigator, but the study did record unidentified sounds and is Internet published. [30]  Other victims have reported an ability to record sounds and voices that harass them. [31] [32]   


Case Report


Tape recordings made by one victim of the above phenomenon 31 were provided to the author for consideration with a notarized affidavit in authentication.  Affiant believes a key component for recording such effects is the Sonic Super Ear personal sound amplifier microphone (or microphones with similar characteristics). [33]  A tripod suspended this microphone about 6 inches behind the top of the affiant’s head while he attempted to sleep.  The sound system also included a RCA model SA155 Mini Stereo Amplifier.   The microphone’s pickup gain was set about ¾ maximum and the RCA amplifier gain set at about ¼ maximum.  A videocassette was also supplied, which was taken by a Cannon ES75 Camcorder mounded on a tripod, and recorded by a SONY model TC WE305 Stereo Cassette Deck on an 8-hour cassette.   Since components should be compatible with the microphone, the affiant has supplied the operating specifications of the components, which is appended.

The audio recordings were compiled on two tapes with a short preamble by the affiant as to the content of each segment, particularly about words understood by the affiant.  The affiant perceived this apparent sound and voice as harassment (particularly to disturb his sleep), and was uncertain as to precise origination.  Though sounds comparable to the words indicated by the affiant could be attributed to the recordings by listening, there was also considerable distortion, and the vocabulary indicated in the examples was limited.  Other sounds that the affiant affirms not to be made by him and intended to harass him at night, resembled snoring or nasal and oropharyngeal sounds.  The provided videocassette contained compiled recordings of similar sound episodes (as well as sounds that may be distorted voice, as so affirmed by the affiant).  The affiant had his eyes closed during these videos, but affirmed he was awake, however his alertness was indeterminate except on voice response.  His mouth appeared closed during most sound episodes, but complete closure could not be determined.  The affiant reports that he has unconsidered videotapes of sound meter readings responsive to local ambient sound, but which he believes do not correlate with those sounds recorded that are understood as transmitted. 

Unfortunately, the vendor of the Sonic Super Ear was unresponsive to repeated inquiry as to specific design, however the condenser microphone design is widely utilized. 20 




Such recordings merit further investigation by more definitive methods, and/or independent experimental replication.  The report for Mind Justice 18 also noted sounds indistinct as to volume or distortion that could be voice, but was inconclusive.  Some radio frequency speech transmission patents 13 14 require pre-distortion of speech signals compatible with sound conditions within the head for intelligibility, and suggest a sphere of similar mass having radio frequency characteristics equivalent to the head intelligibly demodulates such signals, so distortion could be expected from a non-ideal transducer like a microphone.  Of relevance is that the Sonic Super Ear diaphragm cannot be more that ½” in diameter, and the study showing condenser microphone thermoacoustic response 19 appeared to indicate a better response for 1” than ½” diaphragms at high laser pulsation. 

More sophisticated evaluation of the affiant’s recordings than by ear and viewing may be more definitive.  Thermoacoustic experiments have produced waves at the pulsation rate of the electromagnetic source in ultrasound frequencies [34] even into such high rates that can be termed microwave sound [a] with gold films being particularly efficient transducers. [35] [36]  Besides these early studies, similar thermoacoustic methods are presently considered for generating ultrasound of sufficient frequency to improve biomedical image resolution. [37]  Such results raise the interesting possibility that voice transmission devices based on microwave pulse bursts could have a detectable ultrasonic component.  Voice transmission microwave hearing patents based on pulse bursts have such high rates for pulses within bursts that along with normal sound, ultrasonic frequencies from 100 kHz to 40 mHz could be expected from the patent specifications. [38] [39]  Condenser microphones are responsive to the lowest range of such frequencies to capture ultrasound from moths [40] and bats, [41] yet such microphone responsiveness is not clear for preferred patent burst parameters that would indicate ultrasound within bursts of 5 mHz, though responsive transducers do exist for the highest expected ultrasound frequencies as 50 papers are evident on Pubmed search terms of ultrasound and “40 mHz.”   Such ultrasound component would be unlikely to be usual from normal sound.  Studies on microwave-induced thermoacoustic tomography, which induces thermoacoustic responses internally within tissues at ultrasound frequencies, [42] [43] [44] also encourage the prospect that such ultrasound frequencies could be detected from tissues as well, on voice transmission.  However, it is unclear from the specifications that such frequencies would be expected from more recent voice transmission patents, 13 14 as pulsation parameters are omitted with only a Freedom of Information Act release, being briefly informative. [45]








Sonic Super Ear: Personal Sound Amplifier by Sonic Product, Inc.


Audio Gain: .... +50 dB


Max. Signal Output: .... 107 dB


Frequency Response: .... 100 Hz to 14 kHz


Power Requirement: .... 1.5 volt AAA batter, for normal operation upt ot 30 hours



RCA  SA155  Mini Stereo Amplifier


Power Requirement .... 120 Voltes AC, 60 Hz. 25 Watts

Output Power (1% Distortion, 1 kHz, Both Channels Driven) .... 1.8  Watts/Channel (RMS)

Frequency Response .... 20 Hz to 25 kHz

Input Sensitivity:

    A. Phono .... 2.5 mV (Magnetic); 200 mV  (Ceramic)

    B. Tuner .... 160 mV

    C. CD/Tape .... 160 mV

Tape Output .... 150 mV

Speaker Impedance .... 8 to 16 Ohms

Tone Control Response .... -18.0 dB

Crosstalk at CD/Tape Input (@ 2 Watts Power) .... 50 dB @ 1 kHz



SONY TC WE305 Stereo Cassette Deck


Recording System: ... 4-track 2-channel stereo

Fast-winding time (approx.) .... 120 seconds

Bias .... AC bias

S/N Ratio (at peak level and weighted with Dolby NR off)

    A. Type 1 Tape, Sony Type 1 (Normal): .... 55  dB

    B. Type 2 Tape, Sony Type 2 (High): .... 57  dB

    C. Type 4 Tape, Sony Type 4 (Metal) .... 58  dB


S/N Ratio improvement (approx.)

    A. With Dolby NR on: 5 dB @ 1 kHz, 10 dB @ 5  kHz


Harmonic Distortion

    0.4% (with Type 1 tape, Sony Type 1 (Normal)

    160 nWb/m 315 Hz, 3rd. H.D., 1.8% (with Type 4 Tape,  Sony Type 4 (Metal), 250 nWb/m

    315 Hz, 3rd. H.D.


Frequency Response (Dolby off)

    Type 1 Tape, Sony Type 1 (Normal), 30 Hz to 14 kHz,  +/- 3 dB, IEC; 20 to 15 kHz +/- 6 dB

    Type 2 Tape, Sony Type 2 (High), 30 Hz to 15 kHz,  +/- 3 dB, IEC; 20 to 16 kHz +/- 6 dB

    Type 4 Tape, Sony Type 4 (Metal), 30 Hz to 15 kHz  +/- 3 dB, IEC; 20 to 16 kHz +/-6 dB,

    30 to 13 kHz +/- 3 dB, -4 dB Recording.


Wow and Flutter

    A. +/- 0.21% W. Peak, IEC; 015 % W. RMS, NAB; +/-  0.3 % W. Peak, DIN



Line Input (phono jack)

    A. Sensitivity .... 0.16 V

    B. Input impedance: 47 kohms



Line Output (phono jack)

    A. Rated Output Level: 0.5 V @ load of 47  kohms

    B. Load Impedance: over 10 kohms


Power Requirements: 120 V AC, 60 Hz.



SYLVANIA KVS600 Video Cassette Recorder


Television System: .... NTSC, TV standard .... Video Output Level: .... 1  Vp-p

                             .... Video Input Level .... 0.5 to 2.0 Vp-p

Video Heads: .... Rotary 4-head .... Video Output Impedance .... 75  ohms

Tape Cassette: .... VHS video cassette .... Audio Output Level .... -6 dBv  (1 kHz)

Tape Speed:

    A. Recording .... SP, SLP .... Audio Input Level  .... -10 dBv

    B. Playback: .... SP, LP, SLP .... Power  requirements 120 VAC, at 60 Hz


Acknowledgements: Thanks are given to God for inspiration and guidance, as well as Bob Dunlap for collaboration and Christians Against Mental Slavery for web space at




[a]  Not to be confused with electromagnetic microwaves which transmit without fluid or solid media.

[1] Elder JA, Chou CK: Auditory responses to pulsed radiofrequency energy. Bioelectromagnetics 2003; Suppl 8:S162-S173  PubMed abstract.

[2] Lin JC: Auditory perception of pulsed microwave radiation, Chapter 12, in Biological Effects and Medical Applications of Electromagnetic Energy.  Edited by Gandhi OP. Englewood Cliffs, NJ, Prentice Hall, 1990, p 278-318

[3] White RM. “Generation of Elastic Waves by Transient Surface Heating” J Applied Physics 34(11): 3559-67, 1963.

[4] Gournay LS. “Conversion of Electromagnetic to Acoustic Energy by Surface Heating” J Acoust Soc Am 40(6): 1322-30, 1966.

[5] von Gutfeld RJ and Melcher RL. “20-MHz acoustic waves from pulsed themoelastic expansion of constrained surfaces” Applied Physics Letters 30(6): 257-9, 1977.

[6] Foster KR and Finch ED. “Microwave Hearing: Evidence for Thermoacoustic Auditory Stimulation by Pulsed Microwaves” Science 185: 256-58, 1974.

[7] Olsen RG and Lin JC. “Microwave-Induced Pressure Waves in Mammalian Brains” IEEE Trans Biomed Eng 30(5): 1983.

[8] Lin JC, Su J-L, and Wang Y. “Microwave-Induced Thermoelastic Pressure Wave Propagation in the Cat Brain” Bioelectromagnetics 9: 141-7, 1988.

[9] Olsen RG and Hammer WC. “Microwave-Induced Pressure Waves in a Model of Muscle Tissue” Bioelectromagnetics 1: 45-54, 1980.

[10] Olsen RG and Hammer WC. “Evidence for Microwave-Induced Acoustical Resonances in Biological Materials” J Microw Power 16(3 & 4): 263-9, 1981.

[11] Justesen DR. “Microwaves and Behavior” Am Psychologist, 392(Mar): 391-401, 1975. 

[12] Guy AW, Chou CK, Lin JC, and Christensen D. “Microwave-induced Acoustic Effects in Mammalian Auditory Systems and Physical Materials” Ann N Y Acad Sci 247: 194-218, 1975.

[13] O’Loughlin JP, Loree DL. Patent #6470214 “Method and device for implementing the radio frequency hearing effect” USPTO granted 10/22/02.

[14] O’Loughlin JP, Loree DL. Patent #6587729 “Apparatus for audibly communicating speech using the radio frequency hearing effect” USPTO granted 7/1/03.

[15] Uzungolu N and Polychronopoulos SI. “Microwave-Induced Auditory Effect in a Dielectric Sphere” IEEE Transactions in Microwave Theory and Technique 36(10): 1418-25, 1988.  Full article accessed 1/12/05 from IEEE Xplore.

[16] Sharp JC, Grove HM, and Gandhi OP. “Generation of Acoustic Signals by Pulsed Microwave Energy” IEEE Transactions on Microwave Theory and Techniques 22: 583-4, 1974.

[17] Kubota K and Nakatani Y. “Optical Excitation of Acoustic Pulse in Solids” Japanese Journal of Applied Physics 12(6): 888-94, 1973.

[18] Eargle J. The Microphone Book Focal Press, Boston, Oxford, p 30, 2001.

[19] Dioszegny T. “Photoacoustic response of condenser microphones” Journal of Applied Physics 61(1): 449-50, 1987.  Full text available from Inspec.

[20] Eargle J. The Microphone Handbook Elar Publishing, Plainview, New York, p 8-10, 1981.

[21] Huber DM and Runstein RE. Modern Recording Techniques Fourth Edition, SAMS Publishing, Indianapolis, p 96-7, 1995.

[22] Tamura M, Yamaguchi T, Oyaba T, and Yoshimi Y. “Electroacoustic Transducers with Piezoelectric High Polymer Films” In: Audio Engineering Society An anthology of articles on microphones from the pages of the Journal of the Audio Engineering Society Vol. 1 – Vol. 27 (1953-1979) Audio Engineering Society, New York, p 152-7, 1979.

[23] Henni ARH, Bacon C, and Hostan B. “Acoustic generation in piezoelectric materials by microwave excitation” J Acoust Soc Am 118(4): 2281-8, 2005.

[24] McMurtrey JJ. “Inner Voice, Target Tracking, and Behavioral Influence Technologies” in press 2004.  Accessed 8/11/04 at

[25] Mind Justice (Formerly Citizens Against Human Rights Abuse), Director, Cheryl Welsh,  915 Zaragoza Street, Davis, CA 95616, USA.  Website at Email is

[26] Freedom from Covert Harassment and Surveillance. President, Derrick Robinson, P. O. Box 9022. Cincinnati, Ohio 45209. Website at  Email is

[27] Christians Against Mental Slavery, Secretary, John Allman, 98 High Street, Knaresbourough, N. Yorks HG5 0HN, United Kingdom.  Website at  Email is

[28] Moscow Committee for the Ecology of Dwellings, Chairman, Emile Sergeevne Chirkovoi, Korpus 1006, Kvrtira 363, Moscow Zelenograd, Russia 103575.  .  Website at   Email is

[29] International Movement for the Ban of Manipulation of the Human Nervous System by Technologic Means, Founder, Mojmir Babacek, P. O. Box 52, 51101 Turnov, Czech Republic, Europe.  Website at   Email is 

[30] Byrd E. “Report for CAHRA [now Mind Justice]: A Scientific Experiment to Replicate the Recording of Voices that Targeted Individuals Hear” Accessed 8/13/04 at

[31] Dunlap, Bob. Personal communication authenticated by notarized affidavit. Mr Dunlap has extensive audio and video recordings.  He has been willing to provide affidavit thereto as well. Email--   Mr. Dunlap has also had contact with 3 additional victims reporting an ability to record harassing sounds, but they were not willing to have their email published.

[32] Tilton, Margo. Personal Communication. Email-

[33] Sonic Super Ear personal sound amplifier microphone.  Accessed 10/9/04 and available at  This microphone requires an AA battery that according to Mr. Dunlap will last 36 hours before response characteristics deteriorate.

[34] Kubota K. “Optically-Excited Elastic Waves in Solids” Solid State Communications 9: 2045-47, 1971.

[35] Cachier G. “Laser Excitation of Microwave Sound in Solids” Journal of the Acoustical Society of America 49(3): 974-78, 1971.

[36] Brienza MJ and Demaria AJ. “Laser-Induced Microwave Sound by Surface Heating” Applied Physics Letters 11(8): 44-6, 1967.

[37] Acqafresca A, Baigi E, Masotti L, and Menichelli D. “Toward Virtual Biopsy Through an All Fiber Optic Ultrasonic Miniaturized Transducer: A Proposal “ IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 50(10): 1325-35, 2003.  IEEE Xplore accessible.

[38] Brunkan WB. Patent # 4877027 “Hearing system” USPTO granted 10/31/89.  

[39] Leyser R: [Microwave hearing device uses modulated microwave pulses for providing induced sound warning directly within head of deaf person.] Federal Republic of Germany patent # DE10222439, 2003 Dec 11  Abstract available from: URL:  Original German Document available from: URL:  English translation available from: URL:   English translation is also available from the author, and Walter Madlinger at

[40] Jang YW and Greenfield MD. “Ultrasonic communication and sexual selection in wax moths: female choice based on energy and asynchrony of male signals” Animal Behavior 51: 1095-1106, 1996.  Full text at

[41] Helversen Dv, Holderied MW, and Helversen Ov. “Echoes of bat-pollinated bell-shaped flowers: conspicuous for nectar-feeding bats?” Journal of Experimental Biology 206: 1025-34, 2003.  See figure 1 legend for microphone specifications.  Full text available at

[42] Ku G and Wang LV. “Scanning microwave-induced thermoacoustic tomography: Signal, resolution, and contrast” Medical Physics 28(1): 4-10, 2001.

[43] Ku G and Wang LV. “Scanning thermoacoustic tomography in biological tissue” Medical Physics 27(5): 1195-1202, 2000.

[44] Xu Y and Wang LV. “Signal processing in scanning thermoacoustic tomography in biological tissues” Medical Physics 28(7): 1519-24, 2001.

[45] O’Loughlin J. Letter to Ken Callahan, JA. 2001 Aug 30. [Online] [Cited 2007 Mar 13] Available from URL: