The ambisonic motherlode

This project aims at cataloguing, conserving, and making available in digital form as much information as possible about the surround sound framework known as Ambisonics (here, "ambisonic"). We've undertaken this project to ensure that the knowledge is preserved, and to make it easier for fresh implementers to get a hold of a technology we think is both underappreciated and uniquely powerful.

If you think you can help, suggestions, private reserves of information, code and relevant references should be submitted either to the primary editor, or to the sursound mailing list (no attachments, give a live link instead). Digitized material should be delivered as multipage, losslessly compressed TIFF or PDF. Optionally, but also preferably, a lossily encoded and especially an OCR'd version should be included.

Any exclusive rights should be divulged at the time when new materials are submitted, if at all possible. Similarly, complaints about our possible misuse of IP should be raised forthwith—the subject matter is both old and varied enough so that our small group of volunteers simply has no practical, economical means of ascertaining whether we can distribute the material or not. We have to rely solely on feedback.


This section contains an evolving collection of articles on the ambisonic framework. We will try to classify and prioritise them better and more glanularly as time goes by. The aim is to make this into an easily navigatable library of everything there is to know about ambisonic. In the meanwhile all suggestions for further development are welcome, and we sincerely hope you enjoy what we've come up with thus far.

Core ambisonic theory
Title Author(s) Publication information Description
General Metatheory of Auditory Localisation M. A. Gerzon Presented at the 92nd Convention of the AES; 1992-03-24 to 1992-03-27; Vienna, Austria The main theoretical paper underlying the psychoacoustics and the general mathematical formulation of ambisonic.
Further Investigations of High Order Ambisonics and Wavefield Synthesis for Holophonic Sound Imaging J. Daniel, R. Nicol and S. Moreau Presented at the 114th convention of the AES; 2003-03-22 to 2003-03-25; Amsterdam, The Netherlands A highly condensed, and theoretical, yet balanced presentation of the possibilities and the relative limitations of WFS and HOA.
Supporting papers
Title Author(s) Publication information Description
Circular microphone array for discrete multichannel audio recording E. Hulsebos, T. Schuurmans, D. de Vries and R. Boone Presented at the 114th convention of the AES; 2003-03-22 to 2003-03-25; Amsterdam, The Netherlands TEMP!!!
A New Comprehensive Approach of Surround Sound Recording A. Laborie, R. Bruno and S. Montoya Presented at the 114th convention of the AES; 2003-03-22 to 2003-03-25; Amsterdam, The Netherlands TEMP!!!
Applications of Binaural Processing to Surround Sound Reproduction in Large Spaces C. Landone and M. Sandler Presented at IEEE ISCAS; 2000-05-28 to 2000-05-31; Geneva, Switzerland TEMP!!!

Newer, outbound links

Queued material

This is our working area. Unless you're a devoted ambisonic/surround fan, look no further. But if you are, do contact the primary editor of this collection: as soon as you read one of these files through, you're in a position to help us develop this project further. It's little cost to you, and much benefit to the public at large.

File Responsible Comments Should include Should'n include
Microphone array beamforming for multichannel recording SS J. Backman; Presented at the 114th convention of the AES; 2003-03-22 to 2003-03-25; Amsterdam, The Netherlands 1 1
Reproduction of a Plane-Wave Sound Field Using an Array of Loudspeakers SS D. Ward and T. Abhayapala; IEEE Transactions on Speech and Audio Processing, vol. 9, no. 6, 2001-09 1 0
Generalized Encoding and Decoding Functions for a Cylindrical Ambisonic Sound System SS S. Lee and K. Sung; IEEE Signal Processing Letters, vol.10, no.1, 2003-01; this is the proper formulation of cylindrical, not truncated spherical harmonic pantophony 1 0
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source/225-AES-UK-2007.pdf 0 0
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source/3092.pdf 0 0
source/31%20Zmolnig.pdf 0 0
source/3509.pdf 0 0
source/3794.pdf 0 0
source/3aSP8.pdf 0 0
source/3d-ambisonic-based-binaural.pdf 0 0
source/47%20Childs.pdf 0 0
source/5680.pdf 0 0
source/6728.pdf 0 0
source/6730.pdf 0 0
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source/8082.pdf 0 0
source/ACMA2004.pdf 0 0
source/advice_paper.pdf 0 0
source/aella-pres.pdf 0 0
source/aella.pdf 0 0
source/AES-123-conv.pdf 0 0
source/AES112_Contrasting.pdf 0 0
source/AES114_Transform.pdf 0 0
source/AES115_Scalable%20Tri-play%20Recording.pdf 0 0
source/AES116%20High-Passed%20HOA.pdf 0 0
source/AES117_Spatial%20PanAfn.pdf 0 0
source/AES124_Ahrens_HOA_Focussing.pdf 0 0
source/AES125_Spors_WFS_HOA.pdf 0 0
source/AES125_WFS_HOA_talk.pdf 0 0
source/AES19-Malham.pdf 0 0
source/aes2005_v3.pdf 0 0
source/AES21_StPetersburg.pdf 0 0
source/AES23%20NFC%20HOA.pdf 0 0
source/AES24Banff.pdf 0 0
source/AES30_subjective_evaluation_HOA.pdf 0 0
source/AES30_WFS_nearfield.pdf 0 0
source/Ahrens_etal_AES123.pdf 0 0
source/Ahrens_et_al_ICASSP2008.pdf 0 0
source/AlloSphereAudio_01.pdf 0 0
source/ambidvd2001.pdf 0 0
source/AmbiLoc2.pdf 0 0
source/Ambisonics%201.pdf 0 0
source/Ambisonics%202.pdf 0 0
source/ambisonics_around.pdf 0 0
source/AmbiTutorial_en.pdf 0 0
source/article_farina01.pdf 0 0
source/article_farina03.pdf 0 0
source/article_farina05.pdf 0 0
source/article_Neoran_Ben-Hador.pdf 0 0
source/A_Poor_Man%27s_Techniques.pdf 0 0
source/Bates,%20Kearney,%20Boland,%20Furlong%20ASA07.pdf 0 0
source/Beyond51_chen.pdf ML 0 0
source/binaural-sssac.pdf 0 0
source/blah-decoder.pdf 0 0
source/BWPhDThesis.pdf 0 0
source/bw_aes31_paper.pdf 0 0
source/C83%20Limitations%20in%20dynamic%203D%20audio.pdf 0 0
source/CAFSpec.pdf 0 0
source/campo_etal.pdf 0 0
source/cfadaga04_final.pdf 0 0
source/christensen_2001_reverb_mu.pdf 0 0
source/coding2.pdf 0 0
source/dafx00_sound_over_ip.pdf 0 0
source/dafx26.pdf 0 0
source/dafx_sontacchi_hoeldrich.pdf ML 0 0
source/daniel.pdf 0 0
source/Design_Precisely_Coincident_Microphone_Arrays.pdf 0 0
source/Digital_squashing_A4.pdf 0 0
source/directional-source.pdf 0 0
source/Dissonanz_article.pdf 0 0
source/DSP_speakers_scr.pdf 0 0
source/dvd_amb.pdf ML 0 0
source/ele-04-010.pdf 0 0
source/Ethan_Kennedy_2006.pdf 0 0
source/Evans.pdf 0 0
source/ewic_ad98_paper12.pdf 0 0
source/farina99subjective.pdf 0 0
source/Fazi-Nelson_AES123.pdf 0 0
source/Fazi.pdf 0 0
source/Fazi_Nelson_ICA2007.pdf 0 0
source/Fazi_Nelson_IOA07.pdf 0 0
source/Gatzsche-Melchior-ICMC2008_spatial_audio... ML 0 0
source/Geier_etal_ASDF_ICMC_08.pdf ML 0 0
source/getting.pdf 0 0
source/GuastavinoKatz2004JASA.pdf 0 0
source/higher_order_ambisonics.pdf 0 0
source/hoafilt.pdf 0 0
source/HOA_intro.pdf 0 0
source/humphrey_robert_06114.pdf 0 0
source/hyperambisonicsAES.pdf 0 0
source/ICA2007_WFS_HOA_sampling.pdf 0 0
source/ICAD2004.pdf 0 0
source/ICAD2007-CG-VL-GC-PB.pdf 0 0
source/icassp2006.pdf 0 0
source/ICMC-ICAST.pdf 0 0
source/ICMC08_AEP_paper.pdf 0 0
source/ICSP02_sontacchi_hoeldrich.pdf 0 0
source/ICST_Ambisonics_ICMC2006.pdf 0 0
source/id_579_1146654348_271.pdf 0 0
source/Ioana-thesis-s.pdf 0 0
source/ioapaper1.pdf 0 0
source/isbn9512261588.pdf 0 0
source/isbn9512282917.pdf 0 0
source/kim_jonghwa.pdf 0 0
source/krigsman_ambisonics_OK.pdf ML 0 0
source/lac07_adriaensen.pdf 0 0
source/lac07_slides_adriaensen.pdf 0 0
source/lac2006_fons_adriaensen_01.pdf 0 0
source/lac2006_fons_adriaensen_02.pdf 0 0
source/lee-cylindrical-ambi.pdf 0 0
source/Leitner_Sontacchi.pdf 0 0
source/LennoxAes16.pdf ML 0 0
source/lennoxAES19.pdf 0 0
source/linden_ambisonics_OK.pdf 0 0
source/lnt2005_50.pdf 0 0
source/lnt2006_37.pdf 0 0
source/loudspeaker_array_as_a_musical_composition_genre.pdf 0 0
source/martin99b.pdf 0 0
source/MCTChanThesis.pdf 0 0
source/menzies-nearfield.pdf 0 0
source/menzies06_AmbisonicSynthesisOfComplexSources.pdf 0 0
source/menzies06_nearfieldBinauralSynth.pdf 0 0
source/menzies06_nearfieldBinauralSynthesis.pdf 0 0
source/menzies06_O2B.pdf 0 0
source/menzies07_holophonicSynthesisOfMusicalSources.pdf 0 0
source/menzies07_nearfieldBinauralComplexSources.pdf 0 0
source/merimaaaes112.pdf 0 0
source/multi03.pdf 0 0
source/mus02001.pdf 0 0
source/p08_124.pdf 0 0
source/PolackEtAl2005CFADAGA.pdf 0 0
source/poletti_3D surround system.pdf 0 0
source/pulkki04_crosstalk.pdf 0 0
source/pulkkiaes112.pdf 0 0
source/p_221.pdf 0 0
source/rba-15-002.pdf 0 0
source/rdow-multichannelsound.pdf 0 0
source/RM-Gaming_AES121SanFr0610.pdf 0 0
source/Room_Simul_AES107.pdf 0 0
source/rOscar_Liscia.pdf 0 0
source/Schoeps_DoubleMS_Paper.pdf 0 0
source/session2_number3_paper32.pdf 0 0
source/sf_resolution.pdf 0 0
source/SIRRwhitepaper.pdf 0 0
source/SMPTE144-Compatible.pdf 0 0
source/sontacchi01further.pdf ML 0 0
source/Sontacchi_Hoeldrich_DAFX.pdf 0 0
source/SPARG_AES19_Paper1.pdf 0 0
source/SPARG_AES19_Paper2.pdf 0 0
source/SPARG_UKSIM_Paper.pdf 0 0
source/SphericalHarmonics.pdf 0 0
source/Stereo_shuffling_A4.pdf 0 0
source/sur.pdf 0 0
source/Surround_sound_psychoacoustics_A4.pdf 0 0
source/Surround_sound_psychoacoustics_USL.pdf 0 0
source/SweetSpotPaper4407.pdf 0 0
source/theory-and-design-of.pdf 0 0
source/These-original-version.pdf 0 0
source/thesis_a4.pdf 0 0
source/Three_channels_A4.pdf 0 0
source/tmt08.pdf 0 0
source/Trinnov_HSR_5.0_GB.pdf 0 0
source/Tu4.D.5.pdf 0 0
source/ua09.pdf ML 0 0
source/Verron_Aramaki_Kronland-Martinet_Pallone.pdf 0 0
source/virtual-ambisonic.pdf 0 0
source/Vorbis_I_spec.pdf 0 0
source/Vries_JAES_Vol50-10.pdf 0 0
source/What_is_wrong_with_quadraphonics_USL.pdf 0 0
source/360 degrees space in two channels Peter Scheiber 1978.pdf 0 0
source/A computer model of binaural localization_McPherson_1989.pdf 0 0
source/A new approach to the assessment of stereophonic_Bennett et al_1985.pdf 0 0
source/A new process for space related stereophony with improved transmission of spatial information.pdf 0 0
source/Ambisonic Reproduction Of Directionality in Surround_Sound Systems Fellgett 1974.pdf 0 0
source/Ambisonics A Theory for Low Cost High Precision Malham 1990.pdf 0 0
source/Ambisonics Fellgett May 1981.pdf 0 0
source/Ambisonics for audio visual Elen 1983.pdf 0 0
source/Ambisonics Part one Genereal System Description Peter Fellgett 1975 .pdf 0 0
source/Ambisonics The Theory And Patents Adrian Hope 1979.pdf 0 0
source/Ambisonics_Circles of confusion Carbines 1982.pdf 0 0
source/Ambisonics_Questions and answers Elen 1982 .pdf 0 0
source/An image model theory of stereophonic sound_Eckmeier_1989.pdf 0 0
source/andy-moorer.bib 0 0
source/Audio + Design Multi-speaker auditorium decoders.pdf 0 0
source/BBC Quadraphony Matrix H Data.pdf 0 0
source/British patent specification 394325 Blumlein 1933.pdf 0 0
source/catalog.txt 0 0
source/Coding in the auditory nervous system_Whitfield_1967.pdf 0 0
source/Compatible 2-Channel encoding of Surround Sound 1975.pdf 0 0
source/Controlling sound image localization in stereophonic reproduction_Sakamoto et al_1980.pdf 0 0
source/daniel.bib 0 0
source/Design of Ambisonic Decoders for Multispeaker Surround Sound MAG 1977.pdf 0 0
source/Directional Information in Surround Sound Peter Fellgett 1972.pdf 0 0
source/Discrete_Matrix Multichannel Stereo Duane Cooper 1971.pdf 0 0
source/Encoding standards for NRDC Universal HJ 1977.pdf 0 0
source/FM Radio Agnus McKenzie 1977.pdf 0 0
source/gerzon.bib 0 0
source/index.txt 0 0
source/lipshitz-vanderkooy.bib 0 0
source/mics.bib 0 0
source/Motherlode_01.ods 0 0
source/Naturalness and artificiality in recording Fellgett 1981.pdf 0 0
source/On the relation between directional bands and head_Han_1992.pdf 0 0
source/Optimal reproduction matrixes.pdf 0 0
source/Optimum loudspeaker directional patterns_Kates_1980.pdf 0 0
source/Quadraphony Developments in H Matrix Decoding Gaskell Ratliff BBC 1977.pdf 0 0
source/Quadraphony Matrixing and compatability Ben Bauer 1976.pdf 0 0
source/Research at the York University_Malham_.pdf 0 0
source/Scheibers 360 Spatial Decoder Edward Tatnall Canby.pdf 0 0
source/Software implementation of B-Format encoding and decoding_Farina.pdf 0 0
source/Some production facilities available in Ambisonics.pdf 0 0
source/spherical-harmonics.bib 0 0
source/Stereo microphone techniques_arethe purists wrong_Lispshitz_1986_pt1.pdf 0 0
source/Stereo microphone techniques_arethe purists wrong_Lispshitz_1986_pt2.pdf 0 0
source/Subjective evaluation of angular displacement between picture and sound_Komiyama_1989.pdf 0 0
source/Surround Sound Decoders Pts 567 WW 1977.pdf 0 0
source/Surround Sound Patents Adrian Hope 1979.pdf 0 0
source/The development of a compatible 4-2-4 quadraphonic matrix system BBC Matrix H.pdf 0 0
source/The localization of phantom images in a omnidirectional_Moulton et al_1986.pdf 0 0
source/The optimum choice of surround sound specification MAG 1977.pdf 0 0
source/White_Synthesis of 4-2-4 Matrix Recording Systems.pdf 0 0
source/14603.pdf 0 0
source/Ambisonic and B-format user group_Audio Media_1992.pdf 0 0
source/Ambisonic mixing_an introduction_Elen_1983.pdf 0 0
source/Ambisonic operas broadcast_KWMU_1988.pdf 0 0
source/Ambisonic surround sound technology for_Branwell 1983.pdf 0 0
source/Ambisonics revisited_Borwick 1986.pdf 0 0
source/Ambisonics Round and Round_Mike Skeet_1985.pdf 0 0
source/Glyndebourne Panned_Studio Sound_1986.pdf 0 0
source/Hindsight_A possible commercial revival_Barry Fox 1985.pdf 0 0
source/Inside the Alan Parson Project Elen.pdf 0 0
source/keke.txt 0 0
source/KWMU Surround Sound PSN 1984.pdf 0 0
source/Live Surround sound_John Whiting_1986.pdf 0 0
source/MacLennan launches Ambisonic user group_PSN_1992.pdf 0 0
source/Mono Stereo or Ambisonic_Fletcher 1984.pdf 0 0
source/Nimbus_Mastering the classics_AudioMedia_1994.pdf 0 0
source/Report of the APRS BTG Ambisonics Seminar_TA_MJB 1985.pdf 0 0
source/Rundherum das ist nicht schwer Das Ambisonics_1986.pdf 0 0
source/Surround sound for video_David Moore_1986.pdf 0 0
source/Surround sound_Elen 1984.pdf 0 0
source/Surrounded with secrecy_Roger Derry_abt 1989.pdf 0 0
source/Surrounded_Trevor Butler 1989.pdf 0 0
source/The worlds first ambisonic disco_AGM.pdf 0 0
source/TV Ambisonics PSN 1984.pdf 0 0
source/We havent seen the back of Ambisonics_Barry Fox 1987.pdf 0 0
source/Xylos Turbine Power_Caroline Moss_PSN_abt1989.pdf 0 0
source/861 from Meridian_ HiFi News Records Rewiew_ Ken Kessler_1998.pdf 0 0
source/All around my car_Rob Barnlcoat_date unknown.pdf 0 0
source/Ambisonic decoder IMF_Studio Sound_1980.pdf 0 0
source/Ambisonics_Soundfield experience_Richard Elen_Studio Sound_1979.pdf 0 0
source/Ambisonics_The Calrec Soundfield microphone_J Howard Smith_Studio Sound_1979.pdf 0 0
source/AMS Calrec introduce MS stereo mic_AES Convention News_Hamburg_1989.pdf 0 0
source/AMS ST250 stereo microphone_Studio Sound_1990.pdf 0 0
source/Audio Design_Calrec_North American distributor for Minim_Pro Sound News_date unkn.pdf 0 0
source/bai.pdf 0 0
source/baldassin.pdf 0 0
source/bhadkamkar.pdf 0 0
source/bocchino.pdf 0 0
source/boyd-wickizer.pdf 0 0
source/brodman.pdf 0 0
source/Calrec model 3A an operational assessment_Peter Carbines_Studio Sound_1982.pdf 0 0
source/chandy.pdf 0 0
source/dB_Geoffrey Howard_CAR_1986.pdf 0 0
source/Horn of Plenty_abt Nimbus releases_Gramophone_1989.pdf 0 0
source/ICE_A_CC Magazine_date unknown.pdf 0 0
source/Kondensator Microphon QM69_Georg Neumann catalogue_date unknown.pdf 0 0
source/lillibridge.pdf 0 0
source/Listen here_Car Hifi_date unknown.pdf 0 0
source/Machineries of war_Dave Foister_Studio Sound_1995.pdf 0 0
source/Meridian Digital theatre system_Keith Howard_Gramophone_1994.pdf 0 0
source/Meridian KEF high end AV system_Alvin Gold_Gramophone_1998.pdf 0 0
source/Mics below zero_1995.pdf 0 0
source/Minim expand Ambisonic range_Studio Sound_1984.pdf 0 0
source/muniswamy-reddy.pdf 0 0
source/New mics at APRS 89_Tim Frost_Pro Sound News_1989.pdf 0 0
source/Nimbus composite Ambisonic mic uses BK4001_Line Up_1990.pdf 0 0
source/Oceans apart_David Windsor_Motor_1986.pdf 0 0
source/On The Directional Localization of Sound rev6.pdf 0 0
source/ORF Florian Camerer in Frantz Josef land_1995.pdf 0 0
source/plank.pdf 0 0
source/porter.pdf 0 0
source/Richer by far_Motor Magazine_David Windsor_1986.pdf 0 0
source/roscoe.pdf 0 0
source/roy.pdf 0 0
source/Soundfield at Notre Dame_Audio Media_1995 .pdf 0 0
source/Soundfield at Notre Dame_Radio World_1995.pdf 0 0
source/Soundfield at Notre Dame_Studio Sound _1995 .pdf 0 0
source/Soundfield for Stock_Audio Media.pdf 0 0
source/Soundfield go sub zero_Audio media_1995.pdf 0 0
source/Soundfield microphone a new way to record_Elektor_1978.pdf 0 0
source/Soundfield microphone_Design and development pts 1 and 2_Ken Farrar_Wireless World_1977.pdf 0 0
source/Soundfield MK V advertisement.pdf 0 0
source/Soundfield MK V cover story_Audio media_1996.pdf 0 0
source/Soundfield MK V microphone system_leaflet.pdf 0 0
source/Soundfield on show_Audio Media_1993.pdf 0 0
source/Soundfield recording at Notre Dame_Pro Sound News Europe _1995 .pdf 0 0
source/Stock chooses Soundfield MKV for new London studio_Zenon Schoepe .pdf 0 0
source/Technology_Barry Fox_HiFi News Records Rewiew_1994.pdf 0 0
source/temp.txt 0 0
source/The Ambisonic alternative_source unknown.pdf 0 0
source/The Calrec Soundfield microphone system_Nigel Branwell_dB_1982.pdf 0 0
source/The Ghent microphone system for SQ_Bauer_Abbagnaro_Gravereaux_Marshall_AES_1977.pdf 0 0
source/The Ghent microphone system_Ben Bauer_dB_1978.pdf 0 0
source/The Sound Field microphone_J Howard Smith_dB_1978.pdf 0 0
source/The Soundfield microphone_Woram_Sound Recording Handbook.pdf 0 0
source/The worlds first full digital dolby pro logic receiver Onkyo 909_adv_1992.pdf 0 0
source/Troy TA110P Installing the system.pdf 0 0
source/Troy TA110P leaflet.pdf 0 0
source/Troy TA110P Owners Manual.pdf 0 0
source/True stereo sound from Soundfield_Ron Streicher_Radio World_1995.pdf 0 0
source/15665.pdf 0 0
source/2011_TrevinoOkamotoIwayaSuzuki_DecodingIrregLsp_AmbSym.pdf 0 0
source/2011_NettingsmeierDohrmann_LargeScaleHOAStudy_AmbiSym.pdf 0 0
source/2011_NachbarZotterSontacchiDeleflie_ambix_AmbiSym.pdf 0 0
source/2011_PombergerZotter_Warping_AmbiSym.pdf 0 0
source/2011_GuthrieCaulkinsClappBraaschXiang_StageAcoustics_AmbiSym.pdf 0 0
source/2011_GauthierChambatteCamierPascoBerry_IrregMicSFAnalysis_AmbiSym.pdf 0 0

Wishlist (hardcopy/restricted/not located)

This is then the diehard section. Suggestions are again welcome, but there are limits: this is mostly for the few who've preserved hardcopies for the posterity, who otherwise have access to esoteric materials, who can deal out references-long-forgotten, or who've had restricted contacts with credible researchers which bind them from releasing the Beef.

Title Description Date Comments Status Location/contact Priority Reference Should include Shouldn't include
Professional Ambisonic Decoder Design Hardcopy, NRDC ring-binder, 12 pages 1981-07 Horizontal first order UHJ & B-format. Circuits & component lists. I am informed the Abacoid Decoder closely followed this design: I thought highly of the Abacoid when testing and reviewing for Studio Sound Located Peter Carbines High Box #1 1 0
System UHJ Encoding Standards Hardcopy, NRDC bound document, 32 pages 1977-11 Located Peter Carbines High Box #1 1 0
Ambisonics & UHJ Multiplex FM Broadcasting Hardcopy, NRDC bound document, 22 pages 1979 Located Peter Carbines Medium Box #1 1 0
NRDC Periphonic Decoder Hardcopy, Photocopy of Geoff Barton's handwritten document 1979-12 Circuit and construction. Marked "Used for AES Demo Feb 1980" Location kwn Peter Carbines Low Box #1 1 0
Ambisonics: Part One: General System Description Hardcopy, Photocopy of Peter Fellgett's article 1975-08 Studio Sound August 1975 Located Peter Carbines High Box #1 1 0
Ambisonics: Part Two: Studio Techniques Hardcopy, Photocopy of MAG's article 1975-08 Studio Sound August 1975 Located Peter Carbines High Box #1 1 0
Practical Periphony: the Reproduction of Full-Sphere Sound Hardcopy, Photocopy of typewritten draft by MAG 1980-02 Drafted for presentation at 65th AES Convention, London February 1980 Located Peter Carbines High Box #1 1 0
Periphony: With Height Sound Reproducer Hardcopy, MAG paper 1972-03 JAES Vol 21 No 1 Jan/Feb 1973 Located Peter Carbines Medium Box #1 1 0
AMBISONIC TECHNOLOGY: Report #2: Studio Signal Handling Formats and Encoding Hardcopy, Photocopy MAG handwritten report 1975-08 Located Peter Carbines High Box #1 1 0
AMBISONIC TECHNOLOGY: Report #3: Pan Pot and Sound Field Controls Hardcopy, Photocopy MAG handwritten report 1975-08 Located Peter Carbines High Box #1 1 0
AMBISONIC TECHNOLOGY: Report #4: Artificial Reverberation and Spreader Devices Hardcopy, Photocopy MAG handwritten report 1975-08 Includes 'With-height 2-channel spreader' and 'Spread Pan Pot' Located Peter Carbines High Box #1 1 0
AMBISONIC TECHNOLOGY: Hardcopy, Photocopy MAG handwritten report 1978 to 1979 Report #5: incomplete copy of 25 pages. This may NOT be Report 5 as date on documents makes this unlikely. It is included here as it fits with the sequence of reports to NRDC. Design equations and circuits for various manipulative devices: Quadrant Spread pan pot; Ambisonic/Stereo quadrant pan pot; Soundfield Blur Device; Triaxial Pan Pot theory; Quadraxial mixing; Suggested mixer for demonstrations; Multi-input 'wrap' device. Located Peter Carbines Low Box #1 1 0
AMBISONIC TECHNOLOGY: Report #6: Studio Decoders Hardcopy, Photocopy MAG handwritten report 1975-09 Located Peter Carbines High Box #1 1 0
Market Research Report into Consumer Attitudes to Ambisonics Hardcopy, BTG bound document, 70 pages 1981-10 Commissioned report. The Aiwa/Boots Micro-system was used for 'hall' testing. Located Peter Carbines Low-/Historical Box #1 0 1
REPRINTS OF ARTICLES AND REVIEWS Hardcopy, Ambisonic Technology Centre bound document 1992 Prepared for the infamous "Abbey Road" demo. Includes the SS review on the Abacoid Decoder referred to above. Located Peter Carbines Low Box #1 1 0
AMBISONIC SURROUND SOUND SYSTEM Hardcopy, NRDC printed 4-page introductory document Located Peter Carbines Low-/Historical Box #1 0 1
AMBISONIC TECHNOLOGY FOR SURROUND REPRODUCTION OF SOUND Hardcopy, NRDC printed 2-sided A4 page Located Peter Carbines Low-/Historical Box #1 0 1
SOME PRODUCTION FACILITIES AVAILABLE IN AMBISONICS Hardcopy, NRDC bound typescript, 14 pages 1977-11 Located Peter Carbines Low Box #1 1 0
Ambisonic and Wavefield Synthesis Theory and Limitations File, presentation slideset, Christof Faller, lecture at Helsinki University of Technology 2008-02-27 Restricted by an NDA Located Sampo Syreeni Medium 2008_HUT_A_WFS.pdf 1 0
Signal Processing for Audio and Acoustics File, course notes, Christof Faller, at EPFL Lausanne, Switzerland 2008-02-22 Restricted by an NDA Located Sampo Syreeni Low lecture_spatialaudio.pdf 1 0

An ambisonic glossary

It seems that it is impossible to describe all of the stuff in the lode using simple English. Thus, the specialised terms used have to be explained as well. This is why a kind of concept glossary is needed. Again, feel free to contribute to this part as well, in separation from the others. Suggestions for new terms/entries would especially be appreciated, because once you're privy to the literature, it is rather hard to spot the concepts that are the most confusing to a newcomer. Those terms then are clearly also the most worthy of detailed explanation.

Concept Expansion Detailed explanation
45J TEMP!!! TEMP!!!
468-weighting weighting function defined in ITU-R 468 TEMP!!!
A-format raw microphone signals A-format refers to the raw signal set captured directly from microphone array outputs. The term is in particular used with the output of the tetrahedral array within the SoundField mic. These signals are not usually accessible to the production environment, but are instead first transformed into the array independent B-format.
A-weighting TEMP!!! TEMP!!!
active matrix TEMP!!! TEMP!!!
Ambisonic(s) surround sound A comprehensive framework of surround sound capture, processing and reproduction. Ambisonic is distinguished by its ability to reproduce soundfields isotropically even with few channels, by its extensive mathematical underpinnings grounded in the theory of spherical surface harmonic functions, by its tendency towards full holophony at high channel counts, by its use of a microphone and speaker agnostic intermediary format in transmission (B- and C-formats), by a highly developed and physical acoustics based effects infrastructure, and by the presence of a psychoacoustic decoder at the receiver side, which help optimize the final playback for different audiences.
B-format native ambisonic representation of a soundfield This is the standard professional format for ambisonic. Originally it used four signals: W, X, Y and Z. W is the zeroth order spherical harmonic, which is omnidirectional. XYZ are the first order ones which give the dipole moments of the soundfield; that is, they represent fig-8 microphones aligned with the left-right, front-back and top-bottom axes. If only horizontal playback is wished, the Z component (tup-bottom) is discarded.
B-weighting TEMP!!! TEMP!!!
BBC british broadcasting corporation TEMP!!!
BLaH Benjamin, Lee and Heller TEMP!!!
Blumlein pair crossed fig-8's towards L/R TEMP!!!
C-format transmission channel optimized format This is the format that is transmitted to the consumer. It is optimized for the specific transmission channel that is available. C-format also tries to be compatible with the transmission channel, so that ambisonic decoding isn't strictly necessary to yield satisfactory results. Most commonly the channel is a normal stereo one, and the C-format that is then used is the mono and stereo compatible variant of the UHJ hierarchy of encoding methods termed BHJ. Nowadays this could also be G-format, if the transmission channel is 5.0 or 5.1.
C-weighting TEMP!!! TEMP!!!
cardioid (pattern) TEMP!!! TEMP!!!
classical conforming to all of the POA knowledge Quite a number of attempts at implementing ambisonic do not go deep enough into the theory or the tradition to catch even what is already known. That especially happens with ambisonic decoders, because it is far too easy to just go with the beauty of the underlying math, without paying attention to the messy, empirical facts of the field. Thus, "classical" has come to mean something that does pay attention to the tradition, especially on the decoder side. The BLaH series of papers represents a modern attempt to precisely quantify how classical your decoder then is, or in other words how well it follows the most basic psychoacoustics we know about.
compatibility coding coding that is directly listenable in another format UHJ is mono and stereo compatible, Dolby MP is mostly stereo compatible, most quadraphonic systems aimed at the same. TEMP!!!
crosstalk cancellation TEMP!!! TEMP!!!
D-format physical speaker feed signal set This is what is fed to the speakers. In common surround sound and quadrifontal systems this would simply be the transmitted signal set. In ambisonic, however, the transmission format is mic and speaker agnostic. So the eventual speaker feeds have to be derived by an intelligent decoder, which then produces D- format for a specific speaker array.
D-weighting TEMP!!! TEMP!!!
dB decibell A comparative logarithmic scale which utilizes base ten logarithm. It is commonly used in conjunction with perceptually relevant and other measurements which have a wide dynamic range. There are different kinds of dB's for each different base unit, and each different base level used for comparison. The most widely known example is dB (SPL).
dipole TEMP!!! TEMP!!!
(Dolby) MP (Dolby) matrix processing TEMP!!!
DirAC directional audio coding TEMP!!!
distance compensation first order NFC on the decoder side meant to compensate for phase errors, but extends via NFC-HOA to wavefront deconstruction over wider areas. TEMP!!!
discrete (encoding) each channel represents a point/planewave source in the surrounding space TEMP!!!
energy vector TEMP!!! TEMP!!!
figure of eight (fig-8) (pattern) TEMP!!! TEMP!!!
(forward) dominance a transform which amplifies a given direction and pushes sources towards it The dominance, or zoom, transform, amplifies sound in one direction, diminishes it in the opposite one, and at the same time skews the angular distribution of sound sources so that sources are pushed towards the dominant direction. The effect is not unlike an optical zoom lense, only the source directions move opposite to the amplitude enhancement. This control has only been realized at first order, where it technically constitutes a time-invariant Lorentz transform of the first order B-format signal set.
(forward) preference preferential control of phasiness in a given direction, usually forwards When decoding from underdetermined C-format (most commonly BHJ), optimum decoding always leads to some extra phasiness in some part of the decoded soundfield, above that of the best decode of the underlying ambisonic order and the number of speakers in use. The forward preference (sometimes called "focus") control then enables the user to reduce phasiness in the important forward direction at the expense of increasing it elsewhere. This control does not affect directionality at all, but only the distribution of the out-of-phase components that are being reproduced. Contrast with (forward) dominance.
G-format simple predecode of ambisonic for 5.0 a subtype of C-format. TEMP!!!
hierarchical coding coding that extends by only adding more channels UHJ has this, most others don't. MPEG's backwards compatible codecs attempt this, but fall short of the sophistication. TEMP!!!
HJ Matrix H/45J HJ is the name given to the encoding specification jointly agreed to by the BBC and the NRDC, as a result of the fusion of BBC Matrix H and NRDC 45J. It is in the form of a tolerance zone defined on top of the Scheiber sphere, and as such only dictates how two-channel encoding is to be done.
HOA Higher Order Ambisonic The recent development of ambisonic technology so that it can faithfully capture, store and render higher orders of spherical harmonics than just the first two. This yields higher directional accuracy, wider sweet spots, and lessened phasiness even outside the sweet spot. Plus it in theory enables more decoding options, because more data is available. The possibility of higher orders was acknowledged even in the earliest ambisonic papers, but was deemed impracticable at the time. Thus the distinction between POA and HOA might be misleading: this is the same system, it is just that we've only begun to explore its more demanding possibilities. At very high orders HOA converges to genuine holophony.
holophony isotropic surround sound in 3D/all of the space TEMP!!!
HRTF head related transfer function TEMP!!!
hypercardioid (pattern) TEMP!!! TEMP!!!
isotropic TEMP!!! TEMP!!!
K-H (integral) Kirchoff-Helmholtz integral TEMP!!!
kernel (encoding) each channel represents a continuous 3D radiation pattern TEMP!!!
L (channel) TEMP!!! TEMP!!!
M/S mid/side; front facing cardioid plus a sideways fig-8 TEMP!!!
MAG Michael A. Gerzon TEMP!!!
Makita theory TEMP!!! TEMP!!!
Matrix H eighth matrix tested by the BBC TEMP!!!
matrix(ing) TEMP!!! TEMP!!!
MkIV, MkV SoundField microphone, marks four and five TEMP!!!
MLP Meridian lossless packing TEMP!!!
monopole TEMP!!! TEMP!!!
multipole TEMP!!! TEMP!!!
NFC Near Field Correction extended distance compensation, done at the encoding end. remember s/n ratio/headroom. TEMP!!!
NRDC National Research and Development Council TEMP!!!
omni(directional) (pattern) TEMP!!! TEMP!!!
order order of truncation of the spherical harmonic series TEMP!!!
pantophony isotropic surround sound in 2D/in the horizontal plane TEMP!!!
pairwise mixing/panning (style) simulating direction using only the nearest two speakers Pairwise mixing is the practice of locating a mono signal panning between the nearest two loudspeaker feeds in the same general direction. Ambisonic on the other hand assigns mono sources a number of coefficients in B-format, which then translate in the decoding stage to psychoacoustically optimal D-format. The main difference is that all of the speakers are used in unison to reconstruct ambisonic, and their position will be fully taken into account.
passive matrix TEMP!!! TEMP!!!
periphony isotropic surround sound in 3D Periphony means 3D, or "full-sphere" surround sound which doesn't discriminate between any two directions. I.e. it is isotropic. Ambisonic's original 4-channel B-format framework is arguably most notable because it delivers periphony out-of- the-box. Something that other surround sound systems struggle with even today, while using far more channels.
POA Plain Old Ambisonic This is a newly coined short which refers to the sum total of theoretical acoustics and electronic hardware development that once went simply by the name of Ambisonics (here, ambisonic). It has been introduced by the younger folks in the ambisonic scene, mainly because advancing technology has made HOA the center of interest and study. But at the same time, even the most avid enthusiast would still be introduced to ambisonic starting with a subset of POA, and would be hard pressed to acquire even a well functioning periphonic system. Thus, POA retains its place even know, and work continues to improve it, for example in the case of irregular speaker layouts.
pressure field TEMP!!! TEMP!!!
Q (channel) TEMP!!! TEMP!!!
quadraphonic/quadrifontal four channel/speaker Quadraphonic is a term used to describe a system which attempts to produce sound images using four discrete transmission channels. Quadrifontal is a more specific term which also means that the four channels are being played back as four discrete speaker feeds around the listener. Usually at the corners of a square, which at a time seemed like a logical continuation of discrete two-channel stereo. But since the established transmission formats of the time did not permit four discrete channels, matrixing from four to two, and then back to four channels had to be used. When discreteness was then such an issue, all sorts of active decoders were utilized, quite without regard to the possibility of forgoing discreteness altogether, and simply utilizing the limited signal set to its best advantage. To a degree ambisonic was then born as the counter-reaction to this kind of limited thinking.
R (channel) TEMP!!! TEMP!!!
RACE recursive ambiophonic crosstalk elimination TEMP!!!
RM regular matrix TEMP!!!
Scheiber sphere a spherical description of two channel matrix encodings TEMP!!!
SoundField (microphone) the original ambisonic mic, and its derivatives TEMP!!!
soundfield the whole acoustic environment around a listener TEMP!!!
spherical harmonic TEMP!!! TEMP!!!
SPL sound pressure level A comparative scale of absolute sound pressure deviation, with the base unit of pascal, and a reference level of 20 micropascals deviation from standard atmospheric pressure, root mean square integrated over time. The most common use is in conjunction with the logarithmic decibel (dB) scale, which yields dB(SPL). To simulate the ear's sensitivity to different frequencies of sound, a weighting filter is often applied as well. That yields scales such as dB(A).
SQ stereo compatible quad TEMP!!!
steering active matrixing cf. active matrix
subcardioid (pattern) TEMP!!! TEMP!!!
super-stereo ambisonically decoded stereo TEMP!!!
T (channel) TEMP!!! TEMP!!!
TetraMic a modern incarnation of the SoundField microphone TEMP!!!
UHJ the commonest ambisonic compatibility format explain BHJ/SHJ/THJ/etc. hierarchical encoding. compatibility coding. TEMP!!!
variomatrix active matrix cf. active matrix
VBAP vector base amplitude panning The extension of pairwise panning to three dimensions. This is a workable technique when absolute positions of sound sources are known, and the reproduction rig is dense. However, it does not work too well with recorded soundfields where the positions are not exact, nor does it adapt well to irregular reproduction rigs, since pairwise panning is only stable with closely spaced sources.
velocity field TEMP!!! TEMP!!!
velocity vector TEMP!!! TEMP!!!
WFS WaveField Synthesis Ambisonic approaches soundfield synthesis by directional smoothing. Whenever channels are added, the directional response of the system becomes steadily more concentrated, accurate, and less spread out. In the end the system tends to holophony. So does WFS, but it starts differently and converges with different errors along the way. It starts with a large number of equidistant sound sources, usually placed along a line (cf. pantophony). It aims at directly realizing the so called "curtain of microphones", with some added processing to counteract the linear placement of the speakers.
XY crossed cardioids towards L/R TEMP!!!


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