======================AUDIO_HEARING===================================== NEW CHEATSHEETS http://www.idea2ic.com/CheatSheet_2/CHEATSHEETS_2.html These are my personal cheatsheets designed to make access to detailed information much easier to find. They are being put on the web mainly because for now it is easy to do. The new rev of cheatsheets are the ones being continually upgraded. Don Sauer 10/17/09 dsauersanjose@aol.com -------------------------------------------------------------------------------------- ======================AUDIO_CCIR======================================= CCIR A 20 40 50 50 32 30 100 26 19 320 15 6.6 1000 5.5 0 2000 0 1.2 6400 +6.6 0 10000 +2.5 2.5 16000 15 6.6 SPL_dB 20*LOG(Power_ubars/.0002) sound_presure_level 1bar 0.98692 ATM .002ubars soundpressper thresshold hearing I K*p2^2/(rho*c) Sound_intensity_intensity_watts p newtons/m^2 rho kg/m^2 K 1 .0002ubars Iref(0dB) = 1e-16 Watts/cm^2 atom energy K*T/2 joules energry per degree freedom (3/2)*K*T (1/2)*m*Vth^2 ======================AUDIO_HEARING===================================== __ _ / || _/ \_ | \\___/ /_\ | ' ___() ___/ \ `- / - \ inner ear \ / `\\ \_| ear cannal speed of sound 1127 ft. per sec., Frequency Wavelength inches centimeters 20 Hz 676.2 1,717.5 1kHz 13.5 34.4 8kHz 1.7 4.3 20kHz 0.68 1.7 strange hissing between "ker-bumps" of the heart air particles hissing sound only 1/100th of millionth of centimeter, 1/10th diameter of a hydrogen molecule! softest sounds rain of air particles on eardrum. no reason more sensitive rocket blastoff Special protective features of ear protect sensitive mechanism from all but most intense noises. ear canal increases loudness of sounds we hear. pipe-like duct, closed at inner end by eardrum. ____________ / \ / \ ear drum \__/_______\_/ 1/4 wavelength ear canal idealized (straightening out, uniform in diameter) ^ pressure /|\ | * * diameter 0.7cm | * lenght 3 cm | * |____________\ distance / resonance effect maximum effect which 3cm is one quarter wavelength. about 3,000 hertz. Gain 30dB ................................................ | . . . . | . . . . | . . . . | . . . . | . . . . 20dB |.............................B.BB...B........... | . . B. B . | . . B . B . | . . B . B . | . B . . | . . . B . 10dB |......................B...........A............. | . . A .A . | . B . A . A . | . . A . A . | .B B B .A . A . | B . A . . . 0dB |...B.A.......A.................................. | . . . . | . . . . | . . . . dB |________________________________________________ 100Hz 300Hz 1KHz 3 KHz 10kHz Acousfcal amplification at the eardrum. (A) Peak pressure due to pipe resonance of auditory canal (B) Sound pressure at eardrum induding effect of (A) plus an added effect of diffusion amplification resulting from the head disturbing a diffuse sound field. Organ builders aware of an "end effect" which changes effective length of a pipe. Pipe resonance amplifies sound on outer ear 10 dB peaking 2 - 4kHz. overall 20 dB increase where speech energy is concentrated diffraction round the head results in further amplification Diffraction deflection of sound into shadow zone (human head) the head disturbs a diffuse (thoroughly mixed) sound field result in a sort of diffraction resonance further amplification of sound entering auditory canal. The Middle Ear transmit sound from air into water. impedance ratio 4,000 to 1. __ Ossicles _ _/ / __( )) | / |/ \ | / /\ \|__ | / | \_() Oval Window \ / \__/ Ear Drum The ossides (hammer, anvil, and stirrup) of the middle ear transmit vibrations of the eardnrm to the oval window of the inner ear. __| _ | | 80sq mm | | ___. | | \ 1.3 -> 3 |_| \ ___ (@) === | 1 \._|| 3 sq mm || === mechanical analog impedance matching function of the middle ear. differences between eardrum area and oval window area, coupled with stepdown mechanical linkage, matches great motions of the eardrum in air to oval windowÛ working into water. three ossicles hammer, anvil, and stinup) form mechanical linkage between the eardrum and the oval window in intimate contact with fluid of inner ear. hammer, fastened to the eardrum. stinup, actually a part of th' oval window. lever action ratio ranging from 1.3:1 to 3:1. eardrum area about 80 sq mm oval window area only 3 sq mm, reduced ratio 80/3 or about 27 fold. total mechanical force increase between 35 and 80. acoustical impedance air and water 4,000:1, pressure ratio to match two media would be about 63:1 freq vs position idealized unrolled fluid filed cochlea __ / \___ ____/ ^ | ---- ___ ear cannal\' `/------------ ____/ /____----''' \ / || Eustachan tube __---__ 60Hz __---__ 600Hz __--__ 1500Hz amplitude peaks at diff locations vs freq middle ear vented behind nasal cavity by EustachiÛzn tube. eardrum operates as "acoustic suspension" system, acting against compliance of trapped air in middle ear. Eustachian tube suitably small and constricted not destroy compliance. equalizing the air of the middle ear with outside Whenever swallow Eustachian tubes are opened, third emergency function of drainage if ear infected. Hair cells excited by vibratory peaks send signals to brain. conical eardrum at inner end of auditory canal forms one side of the air-filled middle ear. round window separates air-filled middle ear from the practically incompressible fluid of inner ear. Inner Ear about the size of pea encased in solid skull bone. cochlea coiled up like a sea shell from which it gets its name. stretching it out to its full length, about one inch, as shown in Fig. 2-5. fluid filled inner ear divided,lower and upper part by pair membranes. upper part oval window opens into the lower part pressure release , open into round window Vibration of the eardrum causes a rocking motion of oval window. round window moves out When oval window is driven in 50 Hz sound the cochlea standing wave max away from oval window frequency shift position of amplitude peak shifts The peaks shown in Fig. 2-5B are very broad do not explain the sharpness freq discrimination of ear. neural functions effect of sharpening these passbands gives the ear its sharp ability to analyze sounds. Waves in fluid filled duct of the inner ear act on hairlike nerve terminals in the form of neuron discharges to the brain. 24,000 "rods", each with a hair cell dozen or so hairs extend into cochlear liquid. linearity of microphonic potentials over an 80 dB range. nerve fibers 3,000 of them = maximum loudness e perceived. threshold sensitivity a single fiber firing. Gain 120dB|.80..100.......................................... | . . . . . 110dB|60...80..100...................................... | 60 80. . . 100 . 100dB|40.......80...100..........100......100.....100... | 60 .80 . 100 . 100 100 . 100 . 90dB |..40.........80..................100.............. | 60. 80 . . . 80 . 80dB |20..40..........80..........80..80....80.....80... |0 40 . 60 80 80 . 80 . 80. 70dB |..20..40......60.................................. | 0 20 40. . . 60 . 60dB |..0.20..40......60........60...60.....60.....60... | 20 . 60 60 . 60 . 60. 50dB |......20..40...................................... | 0 20. 40 . . . 40 . 40dB |......0.20.......40......40....40.......40.....40. | .20 . . 40 . . 30dB |.........0...20............................20..20. | . 20 . . . 20 20 . 20dB |............0......20..20.20..20......20........0. | . 0 . . 20 . 0 0. 10dB |...................0......................0...0... | . . 0 0 0 0 .0 . 00dB |....................................0............. | . . . . . |_________________________________________________ 20Hz 10Hz 200Hz 1KHz 2kHz 10K phon unit of loudness tied to sound pressure at 1kHz twice loudness for a 10 dB increase in sound pressure level sone. subjective unit of loudness adopted 2 sones is twice as loud, 0. 5 sone half as loud. true subjective unit of loudness (sone) related to loudness level (phon) measured with a sound level meter noise bandwidth affects the loudness of the sound, noise of jet louder than pure tone same dB Sound intensity proportional to the square of sound pressure but not for loudnesss 1KHz centered noise 100 Hz bw 60 phons , loudness of 4 sones. 160 Hz bandwidth, same loudness. 200 Hz bandwidth gets louder critical bandwidth 160 Hz at 1KHz increase with frequency masking a tone at 1K only noise in 160 Hz band effective in masking ear acts like set of filters adjacent to each other. 3rd octaves BW varies as a constant percentage of center frequency (about 23%). approach the critical bandwidths of the ear enough to be useful in certain loudness calculations . ___ | | |<->| _________ |100| |<------->| ___________ | Hz| | 160Hz | |<-200Hz--->| |___| |_________| |___________| 1KHz 1KHz 1KHz Three the same sound pressure level 60 dB. loudness 100 and 160 Hz noises same, 200 Hz band sounds louder exceeds the 160 Hz critical bandwidth of the ear at 1,000 Hz. (Reference 17). 70 ___ | __-- | ___-- 60|_____--- | 200 |____|_|____________| 100 150 1400 Figure 2-9A represents three sounds having the same sound pressure level of 60 dB. Their bandwidths are 100, 160, and 200 Hz, but heights (representing sound intensity per Hz) vary so that areas are equal. In other words, the three sounds have equal intensities. (Sound intensity has a specific meaning in acoustics Critical bandwidth 3000 ............................................ | . . . . | . . . . | . . . . | . . . . | . . . . 1000 |........................................T... | . . . T E. | . . . T E . | . . . T . | . .T E . | . . . . 300 |...............................T............ | . . T . E . | . . T . . | . . T E . . | . . T E . . | . E . . 100 |....E..........E...T........................ | . T . . . | . T . . . | . T . . . dB |____________________________________________ 100Hz 300Hz 1KHz 3 KHz 10kHz ear basically a sound analyzer having critical bandwidths which vary with frequency according to the solid curve. one third octave bandwidths are close enough to critical bands to recommend their use in certain types of measurements HEARING IMPULSES stand out initial transients appear at the end of syllables transients 1,000 Hz tone sounds like 1,000 Hz in 1 second tone burst extremely short burst sounds like a click. Duration of burst influences the perceived loudness. Short bursts do not sound as loud as longer ones. pulse time 3ms pulse need 15 dB higher (500 millisecond) pulse to sound as loud Tones and random noise roughly the same relationship 100 ms Only when sound bursts are shorter than this amount must the sound pressure level be increased to produce a loudness equal to steady tones or noise. 100 ms appears to be time constant of the human ear. Pulse duration millisec 20dB ...TR........................................... | TR . . . . | TR . . . . | R . . . | .R . . . | . T . . . 10dB |...............R................................ | . . . . | . T . . . | . R . . . | . . . . | . R . . 0dB |..........................T..R...T...R.......... | . . . . | . . . . | . . . . dB |________________________________________________ 1 10 100 1K 10k how much the level of shorter pulses have to be increased to have the same loudness as a long pulse or steady tone. ears less sensitive to short transients. direct bearing on understanding speech. consonants of speech determine the meaning of many words. bat, bad, back, bass, the consonants at the end. led,red,shed,bed,fed,and wed consonants at beginning. consonants genuine transients 5 to 15 ms. short need much higher level comparable to longer sounds. places a premium on having good listening conditions speech too high background noise or too much reverberation can cause serious reduction in the understandability of because of the consonant problem ". Pulse duration millisec 20dB ...TR........................................... | TR . . . . | TR . . . . | R . . . | .R . . . | . T . . . 10dB |...............R................................ | . . . . | . T . . . | . R . . . | . . . . | . R . . 0dB |..........................T..R...T...R.......... | . . . . | . . . . | . . . . dB |________________________________________________ 1Hz 10Hz 100Hz 1KHz 10kHz Short pulses of tones or noises are less audible than longer pulses The discontinuity in the 100-200 ms region is related to the integrating Cme of the ear. BINAURAL LOCAUZAnON localize sound response of human ears to very short delays provides basis for determininge direction sounds keener for complex sounds than for tones. very accurate angular discrimination,sounds from directly in front and at eye level. certain confusion between front and back. and sounds arriving at both ears simultaneously head shadow also contributes to locating sounds in the median plane ................................................ | . . . P. | . . . . | . . . . | . . . . | . . . P . 10000|................................................ | . . . . | . . P . . | . . . . | . . P . . | . . . 1000 |................................................ | . P . . . | . P . . . | P. . . . dB |_____P__________________________________________ 10Hz 100Hz 1KHz 10kHz Pitch (in mels, a subjective unit) related to frequency (physical unit) tin heÛ, according to the solid curve obtained by juries of listeners Pitch, subjective term, unit is the mel non-linearly related to freq. pitch of a sound may depend on sound pressure level. 1,000 mels reference pitch , defined as pitch of 1,000 Hz tone with a sound pressure level of 60 dB. It is to be noted on the experimental curve that 1,000 mels coincides with 1,000 Hz which tells the sound pressure level for curve is 60 dB Intensity has its effect on the perception of pitch. low frequencies pitch goes down as intensity of sound is increased. high frequencies pitch increases with intensity. Fletcher reported an interesting illustration of this effect. 168 and 318 Hz normal levels very discordant sound. At a high level hears as a pleasant sound. Timbre perception of complex sounds. applied chiefly to sound ofs musical instruments. each instrument has its own timbre. Tonal Quality close to being a synonym for timbre. another subjective terms. physical term is spectrum. pitch of fund and harmonic both vary with applituce therefore timbre different for different locations EAR nonLINEAR 24 kHz and 23 kHz one can hear a distinct 1,000 Hz tone if tweeters are good and standing in right place. Helmut Haas ear and brain ability of gathering together all reflections arriving within about 50 ms after the direct sound and combining (integrating) them giving impression the direction of original source though reflections from other directions are involved. direction very short delays (less than 1 ms) were involved in discerning direction ofsource by slightly different times of arrival at our two ears. Delays greater than this do not affect directional sense echo Haas found that in the 5-35 ms delay range the sound from the delayed loudspeaker had to be increased more than 10 dB over the direct before it sounded like an echo. Haas Effect. In a room, reflected energy aniving at ear within 50 ms is integrated with the direct sound and is perceived aS part of the direct sound as opposed to reverberant sound. transition zone between the integrating effect, delays less than 50 ms, and delayed sound as an echo is somewhat indefinite. a convenient 1/16th second (62 ms), some at 80 ms, and some at 100 ms 15 ................................................ | . . . . | . . . . | . . . . | . . . . | .E E . E . . 10 |....E.............................E............. | E . . . . | . . . E . | E . . . E. | . . . . | . . . . 5 |E............................................... | . . . . | . . . . | . . . . dB |________________________________________________ 0 10 20 30 40 The Haas Effed or precedence eff act in the human ear. In the 530 ms region echo levels must be abart 10 de higher than the dired sound to be discernable as echoes. In this region of delay refleded components arriving from many directions are all combined by the ear making Re sarnd louder and appear to come from sarrce. For delays greater than the 50-100 ms bansition region reflections are perceived as disaete echoes 1 dB A person is able to detect most of audible band tones frequencies less than 1,000 Hz, tell between tones 0.3 Hz at 100 Hz and 3 Hz at 1,000 Hz. Knowledge of ear's filter-like critical bands leads to tantalizing idea of analyzing continuous noises such as traffic noises, underwater background noises,etc. sound level meter reading is a certain sound pressure level, 20 log (p1/p2) as in Equation 3-3. reference pressure 0.0002 microbar or 0.0002 dyne/cm', corresponds closely to the threshold of human hearing. When a statement is encountered such as, "The sound pressure level is 82 dB" 82dB = 20*log(p1/20uPa) "82 dB SPL" is easier to handle than sound pressure of 251,785. uPa. Overdrive put too large a signal into the input of an amp, causing the signal to be distorted at the speaker. You Boss and Ibanez seemed to define this difference with their pedals. Tube screamer "overdrives" smoother, less harsh sound than DS-1 and SD-9 distortions. distortion pedals add more crunchy, gritty sound, whereas the overdrives add more smoothness and not as much distorted crunch. An MXR "distortion plus" is the definitive distortion pedal from the 1970s. vibrato slight, cyclic change of the frequency of the note, while tremolo" cyclic change in the amplitude of the notes ---------------------------------------------------------------------------- ACOUSTIC 20 micropascal Sound pressure level in air(SPL,dB) 1 picowatt(E-12watt) Power level (Lp, dB) ELECTRIC Power level re 1 mW 10^-3watt(l milliwatt) Voltage level re lV 1volt Volume level VU 10^-3watt 20 uPa 3 dB increase in power level (10 log 2 = 3.01) ------------------------------------------------------------- (decibels, Sound Prrssure A-weighted) (Pa) Saturnrocket 194 1OO,OOO (one atmosphere) Ramjet 160 2,000. Propeller aircraft 140 200. Threshold of pain. 135 Riveter 120 20 Heavy truck 100 2 Noisy office. Heavy traffic r 80 0.2 Conversational 60 0.02 speech Private office 50 Quiet residence 40 0.002 Recording studio 30 Leaves rustling 20 0.0002 Hearing threshold, 10 Hearing threshold 0 0.00002 100,000 Pa (10 kPa) atmospheric pressure 0.00002 Pa (20 uPa), 194-dB detonate 50 pounds of TNT 10 feet away. same order of magnitude as atmospheric pressure. 194 dB sound pressure is rms (root mean square) value. peak sound pressure 1.4 times as great would modulate the atmospheric pressure completely. 20 uPa 2e-5 Newton/m2 ------------------------------------------------------------- Permissible Exposures 0dB silence 8dB threhold hearing 10dB Sound proof room 15dB whisper 20dB empty theater Very faint 30dB quite conversation 40dB private office Faint 45dB awaken sleepomg 50dB normal office 60dB normal conversation Moderate 70dB radio, street Loud 80dB car_70mph loud office 90dB rock band ,factory max 8hr/day 92dB max 6hr/day 95dB max 4hr/day 97dB max 3hr/day 100dB Lawn mower,car horn max 2hr/day Very Loud 110dB close to train max 30min/day 115dB max 15min/day 120dB Thunder max 5min/day 130dB threshold pain 140dB Artillery & Jet immediate damage 196dB Saturn Rocket 10KPa_rms= 1atm 196dB 50lb TNT @ 50ft 10KPa_rms= 1atm 225dB cannon Deafening For Speech, average power is about 10uW ------------------------------------------------------------- Watts Full orchestra 70 Large bass drum 25 Pipe organ 13 Snare drum 12 Cymbals 10 Trombone 6 Piano 0.4 Trumpet 0.3 Basssaxophone 0.3 Basstuba 0.2 Double bass 0.16 Piccolo 0.08 Flute 0.06 Clarinet 0.05 French horn 0.05 Triangle 0.05 ------------------------------------------------------------- audio peak to average 20dB -> 23dB 87dB acoustic power = 1watt/channel rms Sound_pressure_Level SPL = sound_energy/unit_time SPL_dB 20*log(Sound_Pressure_measured_ubars/.0002) 1 Bar .9869Atmosphere = 14.516lbs/sq_in = 100N/sq_meter .0002uBars thresshold of hearing at 1kHz Sound_Intensity soundPower/unit_area Sound_Intensity I (K*P^(2))/(rho*C) 1E-16watts_per_sq_cm @ .0002uBars rho_Kgm_per_cubic_meter density c_meter_per_sec speed of sound P_Newton_per_sq_meter mean square sound pressure ------------------------------------------------------------- CCIR Weighted 20 40 50 32 100 25 320 15 1000 5.5 2000 0 6400 +6.6 10000 +2.5 16000 22 ------------------------------------------------------------- Noise_in_DVM 1dB low pink_noise equal noise per octive red_noise 1/f^2 excess_noise 1/f flicker_noise Sound intensity defined in terms of energy (ergs) transmitted per second over 1 square centimeter surface. energy proportional to velocity of sound. Ergs/cm3 = 2*PI()^2*den_gm/cm3*freq_Hz^2*ampl_cm human ear frequency range from 20 hr (cycle/second) up to 20KHz Perception Changes in Sound vs Sound Level Change in Decibels Perception 3 Barely perceptible. 5 Clearly perceptible 10 Twice as loud Gain 120dB|.........120...................................... | . . . . . 120dB|.................120......120...120.......120..... | . . . 120 . . 110dB|........................................120....... | . . . . . 100dB|................M.......M.....M................... | . . . M . . 90dB |..........................................M....... | M . . . . 80dB |.............................................M.... |0 . . . . . 70dB |.......M.....................S..S................. | . . S S . S M . 60dB |..0................S..................S........... | M . S . . S M . 50dB |.................................................. | 0 M . S . . S. . 40dB |......0.....M......S...S....S..S..............M... | . M . . S M . 30dB |.........0.............M........M................. | . . . . . 20dB |............0..................................... | . 0 . . . 0 0 . 10dB |...................0.........................0.... | . . 0 0 0 0 .0 . 0dB |.....................................0............ | . . . . . |_________________________________________________ 20Hz 10Hz 200Hz 1KHz 2kHz 10K Averaged and approximate sound pressure levels __________________________ | | | A0 _______| 27.3 |_____|||||||||_____ 29.135 | ||||||||| | B0 | 30.86 |_____________|___________ | | | C1 _______| 32.793 |_____|||||||||________34.648 TUBA LOWEST | ||||||||| | D1 _______| 36.708 |_____|||||||||_______ 38.8915 | ||||||||| | E1 | 41.203 |_____________|___________ BASS LOWEST | | | F1 _______| 43.654 |_____|||||||||________ 46.249 | ||||||||| | G1 _______| 48.999 |_____|||||||||________ 51.913 | ||||||||| | A1 _______| 55.000 |_____|||||||||________ 58.270 | ||||||||| | B1 | 61.735 |_____________|___________ FRENCH HORN LO | | | C2 _______| 65.406 |_____|||||||||_______ 69.296 CELLO LOWEST | ||||||||| | D2 _______| 73.416 |_____|||||||||_______ 29.135 | ||||||||| | E2 | 82.407 TROMBONE LOW |_____________|___________ BASS VOICE LOWEST | | | F2 _______| 87.307 |_____|||||||||_______ 93.499 | ||||||||| | G2 _______| 97.99 CLARINET LOW |_____|||||||||_______ 103.83 GUITAR LOWEST | ||||||||| | A2 _______| 110.00 |_____|||||||||_______ 116.54 BARITONE LOW | ||||||||| | B2 | 123.47 |_____________|___________ | | | C3 _______| 130.81 |_____|||||||||_______ 138.59 | ||||||||| | D3 _______| 146.83 |_____|||||||||_______ 155.56 TENOR LO | ||||||||| | E3 | 164.81 |_____________|___________ TRUMPET LOW | | | F3 _______| 174.61 |_____|||||||||_____ 185.00 | ||||||||| | G3 _______| 196.00 VIOLIN LO |_____|||||||||_____ 207.65 ALTO | ||||||||| | A3 _______| 220.00 OBOE LOW |_____|||||||||_____ 233.06 TUBA HI | ||||||||| | B3 | 246.94 |_____________|___________ BASS | | | C4 _______| 261.63 < MIDDLE C > |_____|||||||||_____ 277.18 SOPRANO | ||||||||| | D4 _______| 293.66 |_____|||||||||_____ 311.13 BASS VOICE HI | ||||||||| | E4 | 329.63 |_____________|___________ | | | F4 _______| 349.23 |_____|||||||||_____ 369.99 | ||||||||| | G4 _______| 392.00 BARITONE HI |_____|||||||||_____ 415.3 | ||||||||| | A4 _______| 440.00 TROMBONE HI |_____|||||||||_____ 466.16 TENOR HI | ||||||||| | B4 | 493.38 |_____________|___________ | | | C5 _______| 523.25 < C > |_____|||||||||_____ 554.37 | ||||||||| | D5 _______| 587.33 |_____|||||||||_____ 622.25 | ||||||||| | E5 | 659.26 |_____________|___________ | | FRENCH HORN HI | F5 _______| 698.46 ALTO HI |_____|||||||||_____ 739.99 CELLO HI | ||||||||| | G5 _______| 783.99 |_____|||||||||_____ 830.61 CLARINET HI | ||||||||| | A5 _______| 880.00 |_____|||||||||_____ 932.33 | ||||||||| | B5 | 987.77 |_____________|___________ | | SOPRANO | C6 _______| 1046.5 < HIGH C > |_____|||||||||_____ 1108.7 TRUMPET HI | ||||||||| | D6 _______| 1174.7 |_____|||||||||_____ 1244.5 | ||||||||| | E6 | 1318.5 |_____________|___________ | | | F6 _______| 1396.9 |_____|||||||||_____ 1480.0 | ||||||||| | G6 _______| 1568.0 |_____|||||||||_____ 1661.2 | ||||||||| | A6 _______| 1760.0 |_____|||||||||_____ 1864.7 | ||||||||| | B6 | 1975.5 |_____________|___________ | | | C7 _______| 2093.0 |_____|||||||||_____ 2217.5 VIOLIN HI | ||||||||| | D7 _______| 2349.3 |_____|||||||||_____ 2489.0 | ||||||||| | E7 | 2637.0 |_____________|___________ | | | F7 _______| 2793.3 |_____|||||||||_____ 2960.0 | ||||||||| | G7 _______| 3134.0 |_____|||||||||_____ 3322.4 | ||||||||| | A7 _______| 3520.0 |_____|||||||||_____ 3729.3 | ||||||||| | B7 | 3951.1 |_____________|___________ | | | C8 | 4186.0 |_____________| ======================CIRCUITS_AUDIO======================================= CCIR A 20 40 50 50 32 30 100 26 19 320 15 6.6 1000 5.5 0 2000 0 1.2 6400 +6.6 0 10000 +2.5 2.5 16000 15 6.6 SPL_dB 20*LOG(Power_ubars/.0002) sound_presure_level 1bar 0.98692 ATM .002ubars soundpressper thresshold hearing I K*p2^2/(rho*c) Sound_intensity_intensity_watts p newtons/m^2 rho kg/m^2 K 1 .0002ubars Iref(0dB) = 1e-16 Watts/cm^2 atom energy K*T/2 joules energry per degree freedom (3/2)*K*T (1/2)*m*Vth^2 AUDIO_HEARING __ _ / || _/ \_ | \\___/ /_\ | ' ___() ___/ \ `- / - \ inner ear \ / `\\ \_| ear cannal speed of sound 1127 ft. per sec., Frequency Wavelength inches centimeters 20 Hz 676.2 1,717.5 1kHz 13.5 34.4 8kHz 1.7 4.3 20kHz 0.68 1.7 strange hissing between "ker-bumps" of the heart air particles hissing sound only 1/100th of millionth of centimeter, 1/10th diameter of a hydrogen molecule! softest sounds rain of air particles on eardrum. no reason more sensitive rocket blastoff Special protective features of ear protect sensitive mechanism from all but most intense noises. ear canal increases loudness of sounds we hear. pipe-like duct, closed at inner end by eardrum. ____________ / \ / \ ear drum \__/_______\_/ 1/4 wavelength ear canal idealized (straightening out, uniform in diameter) ^ pressure /|\ | * * diameter 0.7cm | * lenght 3 cm | * |____________\ distance / resonance effect maximum effect which 3cm is one quarter wavelength. about 3,000 hertz. Gain 30dB ................................................ | . . . . | . . . . | . . . . | . . . . | . . . . 20dB |.............................B.BB...B........... | . . B. B . | . . B . B . | . . B . B . | . B . . | . . . B . 10dB |......................B...........A............. | . . A .A . | . B . A . A . | . . A . A . | .B B B .A . A . | B . A . . . 0dB |...B.A.......A.................................. | . . . . | . . . . | . . . . dB |________________________________________________ 100Hz 300Hz 1KHz 3 KHz 10kHz Acousfcal amplification at the eardrum. (A) Peak pressure due to pipe resonance of auditory canal (B) Sound pressure at eardrum induding effect of (A) plus an added effect of diffusion amplification resulting from the head disturbing a diffuse sound field. Organ builders aware of an "end effect" which changes effective length of a pipe. Pipe resonance amplifies sound on outer ear 10 dB peaking 2 - 4kHz. overall 20 dB increase where speech energy is concentrated diffraction round the head results in further amplification Diffraction deflection of sound into shadow zone (human head) the head disturbs a diffuse (thoroughly mixed) sound field result in a sort of diffraction resonance further amplification of sound entering auditory canal. The Middle Ear transmit sound from air into water. impedance ratio 4,000 to 1. __ Ossicles _ _/ / __( )) | / |/ \ | / /\ \|__ | / | \_() Oval Window \ / \__/ Ear Drum The ossides (hammer, anvil, and stirrup) of the middle ear transmit vibrations of the eardnrm to the oval window of the inner ear. __| _ | | 80sq mm | | ___. | | \ 1.3 -> 3 |_| \ ___ (@) === | 1 \._|| 3 sq mm || === mechanical analog impedance matching function of the middle ear. differences between eardrum area and oval window area, coupled with stepdown mechanical linkage, matches great motions of the eardrum in air to oval windowÛ working into water. three ossicles hammer, anvil, and stinup) form mechanical linkage between the eardrum and the oval window in intimate contact with fluid of inner ear. hammer, fastened to the eardrum. stinup, actually a part of th' oval window. lever action ratio ranging from 1.3:1 to 3:1. eardrum area about 80 sq mm oval window area only 3 sq mm, reduced ratio 80/3 or about 27 fold. total mechanical force increase between 35 and 80. acoustical impedance air and water 4,000:1, pressure ratio to match two media would be about 63:1 freq vs position idealized unrolled fluid filed cochlea __ / \___ ____/ ^ | ---- ___ ear cannal\' `/------------ ____/ /____----''' \ / || Eustachan tube __---__ 60Hz __---__ 600Hz __--__ 1500Hz amplitude peaks at diff locations vs freq middle ear vented behind nasal cavity by EustachiÛzn tube. eardrum operates as "acoustic suspension" system, acting against compliance of trapped air in middle ear. Eustachian tube suitably small and constricted not destroy compliance. equalizing the air of the middle ear with outside Whenever swallow Eustachian tubes are opened, third emergency function of drainage if ear infected. Hair cells excited by vibratory peaks send signals to brain. conical eardrum at inner end of auditory canal forms one side of the air-filled middle ear. round window separates air-filled middle ear from the practically incompressible fluid of inner ear. Inner Ear about the size of pea encased in solid skull bone. cochlea coiled up like a sea shell from which it gets its name. stretching it out to its full length, about one inch, as shown in Fig. 2-5. fluid filled inner ear divided,lower and upper part by pair membranes. upper part oval window opens into the lower part pressure release , open into round window Vibration of the eardrum causes a rocking motion of oval window. round window moves out When oval window is driven in 50 Hz sound the cochlea standing wave max away from oval window frequency shift position of amplitude peak shifts The peaks shown in Fig. 2-5B are very broad do not explain the sharpness freq discrimination of ear. neural functions effect of sharpening these passbands gives the ear its sharp ability to analyze sounds. Waves in fluid filled duct of the inner ear act on hairlike nerve terminals in the form of neuron discharges to the brain. 24,000 "rods", each with a hair cell dozen or so hairs extend into cochlear liquid. linearity of microphonic potentials over an 80 dB range. nerve fibers 3,000 of them = maximum loudness e perceived. threshold sensitivity a single fiber firing. Gain 120dB|.80..100.......................................... | . . . . . 110dB|60...80..100...................................... | 60 80. . . 100 . 100dB|40.......80...100..........100......100.....100... | 60 .80 . 100 . 100 100 . 100 . 90dB |..40.........80..................100.............. | 60. 80 . . . 80 . 80dB |20..40..........80..........80..80....80.....80... |0 40 . 60 80 80 . 80 . 80. 70dB |..20..40......60.................................. | 0 20 40. . . 60 . 60dB |..0.20..40......60........60...60.....60.....60... | 20 . 60 60 . 60 . 60. 50dB |......20..40...................................... | 0 20. 40 . . . 40 . 40dB |......0.20.......40......40....40.......40.....40. | .20 . . 40 . . 30dB |.........0...20............................20..20. | . 20 . . . 20 20 . 20dB |............0......20..20.20..20......20........0. | . 0 . . 20 . 0 0. 10dB |...................0......................0...0... | . . 0 0 0 0 .0 . 00dB |....................................0............. | . . . . . |_________________________________________________ 20Hz 10Hz 200Hz 1KHz 2kHz 10K phon unit of loudness tied to sound pressure at 1kHz twice loudness for a 10 dB increase in sound pressure level sone. subjective unit of loudness adopted 2 sones is twice as loud, 0. 5 sone half as loud. true subjective unit of loudness (sone) related to loudness level (phon) measured with a sound level meter noise bandwidth affects the loudness of the sound, noise of jet louder than pure tone same dB Sound intensity proportional to the square of sound pressure but not for loudnesss 1KHz centered noise 100 Hz bw 60 phons , loudness of 4 sones. 160 Hz bandwidth, same loudness. 200 Hz bandwidth gets louder critical bandwidth 160 Hz at 1KHz increase with frequency masking a tone at 1K only noise in 160 Hz band effective in masking ear acts like set of filters adjacent to each other. 3rd octaves BW varies as a constant percentage of center frequency (about 23%). approach the critical bandwidths of the ear enough to be useful in certain loudness calculations . ___ | | |<->| _________ |100| |<------->| ___________ | Hz| | 160Hz | |<-200Hz--->| |___| |_________| |___________| 1KHz 1KHz 1KHz Three the same sound pressure level 60 dB. loudness 100 and 160 Hz noises same, 200 Hz band sounds louder exceeds the 160 Hz critical bandwidth of the ear at 1,000 Hz. (Reference 17). 70 ___ | __-- | ___-- 60|_____--- | 200 |____|_|____________| 100 150 1400 Figure 2-9A represents three sounds having the same sound pressure level of 60 dB. Their bandwidths are 100, 160, and 200 Hz, but heights (representing sound intensity per Hz) vary so that areas are equal. In other words, the three sounds have equal intensities. (Sound intensity has a specific meaning in acoustics Critical bandwidth 3000 ............................................ | . . . . | . . . . | . . . . | . . . . | . . . . 1000 |........................................T... | . . . T E. | . . . T E . | . . . T . | . .T E . | . . . . 300 |...............................T............ | . . T . E . | . . T . . | . . T E . . | . . T E . . | . E . . 100 |....E..........E...T........................ | . T . . . | . T . . . | . T . . . dB |____________________________________________ 100Hz 300Hz 1KHz 3 KHz 10kHz ear basically a sound analyzer having critical bandwidths which vary with frequency according to the solid curve. one third octave bandwidths are close enough to critical bands to recommend their use in certain types of measurements HEARING IMPULSES stand out initial transients appear at the end of syllables transients 1,000 Hz tone sounds like 1,000 Hz in 1 second tone burst extremely short burst sounds like a click. Duration of burst influences the perceived loudness. Short bursts do not sound as loud as longer ones. pulse time 3ms pulse need 15 dB higher (500 millisecond) pulse to sound as loud Tones and random noise roughly the same relationship 100 ms Only when sound bursts are shorter than this amount must the sound pressure level be increased to produce a loudness equal to steady tones or noise. 100 ms appears to be time constant of the human ear. Pulse duration millisec 20dB ...TR........................................... | TR . . . . | TR . . . . | R . . . | .R . . . | . T . . . 10dB |...............R................................ | . . . . | . T . . . | . R . . . | . . . . | . R . . 0dB |..........................T..R...T...R.......... | . . . . | . . . . | . . . . dB |________________________________________________ 1 10 100 1K 10k how much the level of shorter pulses have to be increased to have the same loudness as a long pulse or steady tone. ears less sensitive to short transients. direct bearing on understanding speech. consonants of speech determine the meaning of many words. bat, bad, back, bass, the consonants at the end. led,red,shed,bed,fed,and wed consonants at beginning. consonants genuine transients 5 to 15 ms. short need much higher level comparable to longer sounds. places a premium on having good listening conditions speech too high background noise or too much reverberation can cause serious reduction in the understandability of because of the consonant problem ". Pulse duration millisec 20dB ...TR........................................... | TR . . . . | TR . . . . | R . . . | .R . . . | . T . . . 10dB |...............R................................ | . . . . | . T . . . | . R . . . | . . . . | . R . . 0dB |..........................T..R...T...R.......... | . . . . | . . . . | . . . . dB |________________________________________________ 1Hz 10Hz 100Hz 1KHz 10kHz Short pulses of tones or noises are less audible than longer pulses The discontinuity in the 100-200 ms region is related to the integrating Cme of the ear. BINAURAL LOCAUZAnON localize sound response of human ears to very short delays provides basis for determininge direction sounds keener for complex sounds than for tones. very accurate angular discrimination,sounds from directly in front and at eye level. certain confusion between front and back. and sounds arriving at both ears simultaneously head shadow also contributes to locating sounds in the median plane ................................................ | . . . P. | . . . . | . . . . | . . . . | . . . P . 10000|................................................ | . . . . | . . P . . | . . . . | . . P . . | . . . 1000 |................................................ | . P . . . | . P . . . | P. . . . dB |_____P__________________________________________ 10Hz 100Hz 1KHz 10kHz Pitch (in mels, a subjective unit) related to frequency (physical unit) tin heÛ, according to the solid curve obtained by juries of listeners Pitch, subjective term, unit is the mel non-linearly related to freq. pitch of a sound may depend on sound pressure level. 1,000 mels reference pitch , defined as pitch of 1,000 Hz tone with a sound pressure level of 60 dB. It is to be noted on the experimental curve that 1,000 mels coincides with 1,000 Hz which tells the sound pressure level for curve is 60 dB Intensity has its effect on the perception of pitch. low frequencies pitch goes down as intensity of sound is increased. high frequencies pitch increases with intensity. Fletcher reported an interesting illustration of this effect. 168 and 318 Hz normal levels very discordant sound. At a high level hears as a pleasant sound. Timbre perception of complex sounds. applied chiefly to sound ofs musical instruments. each instrument has its own timbre. Tonal Quality close to being a synonym for timbre. another subjective terms. physical term is spectrum. pitch of fund and harmonic both vary with applituce therefore timbre different for different locations EAR nonLINEAR 24 kHz and 23 kHz one can hear a distinct 1,000 Hz tone if tweeters are good and standing in right place. Helmut Haas ear and brain ability of gathering together all reflections arriving within about 50 ms after the direct sound and combining (integrating) them giving impression the direction of original source though reflections from other directions are involved. direction very short delays (less than 1 ms) were involved in discerning direction ofsource by slightly different times of arrival at our two ears. Delays greater than this do not affect directional sense echo Haas found that in the 5-35 ms delay range the sound from the delayed loudspeaker had to be increased more than 10 dB over the direct before it sounded like an echo. Haas Effect. In a room, reflected energy aniving at ear within 50 ms is integrated with the direct sound and is perceived aS part of the direct sound as opposed to reverberant sound. transition zone between the integrating effect, delays less than 50 ms, and delayed sound as an echo is somewhat indefinite. a convenient 1/16th second (62 ms), some at 80 ms, and some at 100 ms 15 ................................................ | . . . . | . . . . | . . . . | . . . . | .E E . E . . 10 |....E.............................E............. | E . . . . | . . . E . | E . . . E. | . . . . | . . . . 5 |E............................................... | . . . . | . . . . | . . . . dB |________________________________________________ 0 10 20 30 40 The Haas Effed or precedence eff act in the human ear. In the 530 ms region echo levels must be abart 10 de higher than the dired sound to be discernable as echoes. In this region of delay refleded components arriving from many directions are all combined by the ear making Re sarnd louder and appear to come from sarrce. For delays greater than the 50-100 ms bansition region reflections are perceived as disaete echoes 1 dB A person is able to detect most of audible band tones frequencies less than 1,000 Hz, tell between tones 0.3 Hz at 100 Hz and 3 Hz at 1,000 Hz. Knowledge of ear's filter-like critical bands leads to tantalizing idea of analyzing continuous noises such as traffic noises, underwater background noises,etc. sound level meter reading is a certain sound pressure level, 20 log (p1/p2) as in Equation 3-3. reference pressure 0.0002 microbar or 0.0002 dyne/cm', corresponds closely to the threshold of human hearing. When a statement is encountered such as, "The sound pressure level is 82 dB" 82dB = 20*log(p1/20uPa) "82 dB SPL" is easier to handle than sound pressure of 251,785. uPa. Overdrive put too large a signal into the input of an amp, causing the signal to be distorted at the speaker. You Boss and Ibanez seemed to define this difference with their pedals. Tube screamer "overdrives" smoother, less harsh sound than DS-1 and SD-9 distortions. distortion pedals add more crunchy, gritty sound, whereas the overdrives add more smoothness and not as much distorted crunch. An MXR "distortion plus" is the definitive distortion pedal from the 1970s. vibrato slight, cyclic change of the frequency of the note, while tremolo" cyclic change in the amplitude of the notes ---------------------------------------------------------------------------- ACOUSTIC 20 micropascal Sound pressure level in air(SPL,dB) 1 picowatt(E-12watt) Power level (Lp, dB) ELECTRIC Power level re 1 mW 10^-3watt(l milliwatt) Voltage level re lV 1volt Volume level VU 10^-3watt 20 uPa 3 dB increase in power level (10 log 2 = 3.01) ------------------------------------------------------------- (decibels, Sound Prrssure A-weighted) (Pa) Saturnrocket 194 1OO,OOO (one atmosphere) Ramjet 160 2,000. Propeller aircraft 140 200. Threshold of pain. 135 Riveter 120 20 Heavy truck 100 2 Noisy office. Heavy traffic r 80 0.2 Conversational 60 0.02 speech Private office 50 Quiet residence 40 0.002 Recording studio 30 Leaves rustling 20 0.0002 Hearing threshold, 10 Hearing threshold 0 0.00002 100,000 Pa (10 kPa) atmospheric pressure 0.00002 Pa (20 uPa), 194-dB detonate 50 pounds of TNT 10 feet away. same order of magnitude as atmospheric pressure. 194 dB sound pressure is rms (root mean square) value. peak sound pressure 1.4 times as great would modulate the atmospheric pressure completely. 20 uPa 2e-5 Newton/m2 ------------------------------------------------------------- Permissible Exposures 0dB silence 8dB threhold hearing 10dB Sound proof room 15dB whisper 20dB empty theater Very faint 30dB quite conversation 40dB private office Faint 45dB awaken sleepomg 50dB normal office 60dB normal conversation Moderate 70dB radio, street Loud 80dB car_70mph loud office 90dB rock band ,factory max 8hr/day 92dB max 6hr/day 95dB max 4hr/day 97dB max 3hr/day 100dB Lawn mower,car horn max 2hr/day Very Loud 110dB close to train max 30min/day 115dB max 15min/day 120dB Thunder max 5min/day 130dB threshold pain 140dB Artillery & Jet immediate damage 196dB Saturn Rocket 10KPa_rms= 1atm 196dB 50lb TNT @ 50ft 10KPa_rms= 1atm 225dB cannon Deafening For Speech, average power is about 10uW ------------------------------------------------------------- Watts Full orchestra 70 Large bass drum 25 Pipe organ 13 Snare drum 12 Cymbals 10 Trombone 6 Piano 0.4 Trumpet 0.3 Basssaxophone 0.3 Basstuba 0.2 Double bass 0.16 Piccolo 0.08 Flute 0.06 Clarinet 0.05 French horn 0.05 Triangle 0.05 ------------------------------------------------------------- audio peak to average 20dB -> 23dB 87dB acoustic power = 1watt/channel rms Sound_pressure_Level SPL = sound_energy/unit_time SPL_dB 20*log(Sound_Pressure_measured_ubars/.0002) 1 Bar .9869Atmosphere = 14.516lbs/sq_in = 100N/sq_meter .0002uBars thresshold of hearing at 1kHz Sound_Intensity soundPower/unit_area Sound_Intensity I (K*P^(2))/(rho*C) 1E-16watts_per_sq_cm @ .0002uBars rho_Kgm_per_cubic_meter density c_meter_per_sec speed of sound P_Newton_per_sq_meter mean square sound pressure ------------------------------------------------------------- CCIR Weighted 20 40 50 32 100 25 320 15 1000 5.5 2000 0 6400 +6.6 10000 +2.5 16000 22 ------------------------------------------------------------- Noise_in_DVM 1dB low pink_noise equal noise per octive red_noise 1/f^2 excess_noise 1/f flicker_noise Sound intensity defined in terms of energy (ergs) transmitted per second over 1 square centimeter surface. energy proportional to velocity of sound. Ergs/cm3 = 2*PI()^2*den_gm/cm3*freq_Hz^2*ampl_cm human ear frequency range from 20 hr (cycle/second) up to 20KHz Perception Changes in Sound vs Sound Level Change in Decibels Perception 3 Barely perceptible. 5 Clearly perceptible 10 Twice as loud Gain 120dB|.........120...................................... | . . . . . 120dB|.................120......120...120.......120..... | . . . 120 . . 110dB|........................................120....... | . . . . . 100dB|................M.......M.....M................... | . . . M . . 90dB |..........................................M....... | M . . . . 80dB |.............................................M.... |0 . . . . . 70dB |.......M.....................S..S................. | . . S S . S M . 60dB |..0................S..................S........... | M . S . . S M . 50dB |.................................................. | 0 M . S . . S. . 40dB |......0.....M......S...S....S..S..............M... | . M . . S M . 30dB |.........0.............M........M................. | . . . . . 20dB |............0..................................... | . 0 . . . 0 0 . 10dB |...................0.........................0.... | . . 0 0 0 0 .0 . 0dB |.....................................0............ | . . . . . |_________________________________________________ 20Hz 10Hz 200Hz 1KHz 2kHz 10K Averaged and approximate sound pressure levels __________________________ | | | A0 _______| 27.3 |_____|||||||||_____ 29.135 | ||||||||| | B0 | 30.86 |_____________|___________ | | | C1 _______| 32.793 |_____|||||||||________34.648 TUBA LOWEST | ||||||||| | D1 _______| 36.708 |_____|||||||||_______ 38.8915 | ||||||||| | E1 | 41.203 |_____________|___________ BASS LOWEST | | | F1 _______| 43.654 |_____|||||||||________ 46.249 | ||||||||| | G1 _______| 48.999 |_____|||||||||________ 51.913 | ||||||||| | A1 _______| 55.000 |_____|||||||||________ 58.270 | ||||||||| | B1 | 61.735 |_____________|___________ FRENCH HORN LO | | | C2 _______| 65.406 |_____|||||||||_______ 69.296 CELLO LOWEST | ||||||||| | D2 _______| 73.416 |_____|||||||||_______ 29.135 | ||||||||| | E2 | 82.407 TROMBONE LOW |_____________|___________ BASS VOICE LOWEST | | | F2 _______| 87.307 |_____|||||||||_______ 93.499 | ||||||||| | G2 _______| 97.99 CLARINET LOW |_____|||||||||_______ 103.83 GUITAR LOWEST | ||||||||| | A2 _______| 110.00 |_____|||||||||_______ 116.54 BARITONE LOW | ||||||||| | B2 | 123.47 |_____________|___________ | | | C3 _______| 130.81 |_____|||||||||_______ 138.59 | ||||||||| | D3 _______| 146.83 |_____|||||||||_______ 155.56 TENOR LO | ||||||||| | E3 | 164.81 |_____________|___________ TRUMPET LOW | | | F3 _______| 174.61 |_____|||||||||_____ 185.00 | ||||||||| | G3 _______| 196.00 VIOLIN LO |_____|||||||||_____ 207.65 ALTO | ||||||||| | A3 _______| 220.00 OBOE LOW |_____|||||||||_____ 233.06 TUBA HI | ||||||||| | B3 | 246.94 |_____________|___________ BASS | | | C4 _______| 261.63 < MIDDLE C > |_____|||||||||_____ 277.18 SOPRANO | ||||||||| | D4 _______| 293.66 |_____|||||||||_____ 311.13 BASS VOICE HI | ||||||||| | E4 | 329.63 |_____________|___________ | | | F4 _______| 349.23 |_____|||||||||_____ 369.99 | ||||||||| | G4 _______| 392.00 BARITONE HI |_____|||||||||_____ 415.3 | ||||||||| | A4 _______| 440.00 TROMBONE HI |_____|||||||||_____ 466.16 TENOR HI | ||||||||| | B4 | 493.38 |_____________|___________ | | | C5 _______| 523.25 < C > |_____|||||||||_____ 554.37 | ||||||||| | D5 _______| 587.33 |_____|||||||||_____ 622.25 | ||||||||| | E5 | 659.26 |_____________|___________ | | FRENCH HORN HI | F5 _______| 698.46 ALTO HI |_____|||||||||_____ 739.99 CELLO HI | ||||||||| | G5 _______| 783.99 |_____|||||||||_____ 830.61 CLARINET HI | ||||||||| | A5 _______| 880.00 |_____|||||||||_____ 932.33 | ||||||||| | B5 | 987.77 |_____________|___________ | | SOPRANO | C6 _______| 1046.5 < HIGH C > |_____|||||||||_____ 1108.7 TRUMPET HI | ||||||||| | D6 _______| 1174.7 |_____|||||||||_____ 1244.5 | ||||||||| | E6 | 1318.5 |_____________|___________ | | | F6 _______| 1396.9 |_____|||||||||_____ 1480.0 | ||||||||| | G6 _______| 1568.0 |_____|||||||||_____ 1661.2 | ||||||||| | A6 _______| 1760.0 |_____|||||||||_____ 1864.7 | ||||||||| | B6 | 1975.5 |_____________|___________ | | | C7 _______| 2093.0 |_____|||||||||_____ 2217.5 VIOLIN HI | ||||||||| | D7 _______| 2349.3 |_____|||||||||_____ 2489.0 | ||||||||| | E7 | 2637.0 |_____________|___________ | | | F7 _______| 2793.3 |_____|||||||||_____ 2960.0 | ||||||||| | G7 _______| 3134.0 |_____|||||||||_____ 3322.4 | ||||||||| | A7 _______| 3520.0 |_____|||||||||_____ 3729.3 | ||||||||| | B7 | 3951.1 |_____________|___________ | | | C8 | 4186.0 |_____________| EFFECTS DESCRIPTIONS AMPLITUDE BASED EFFECTS Volume control Manual level control. Twist knob, sound louder or. Examples : Morley and DeArmond Volume pedals ('70s) Tremolo Cyclical variation volume by low frequency oscillator parameters are waveform of LFO, LFO frequency, and depth modulation; tremolo and vibrato are often used interchangeably, tremolo actually variation loudness, vibrato variation in pitch or frequency. Auto tremolo tremolo where modulation frequency varied by the input signal, generally amplitude. Panning/ping-pong generalization tremolo more one channel; one channel goes down level, another up. With non-square LFO waveforms effect of sound source moving from place to place or Gating/repeat percussion tremolo 100% modulation by a square wave. exponentially decaying waveforms (guitar ), gives the effect of striking same note again at decreasing levels. Compression soft inputs louder, loud ones softer, giving a one-level of sound with lessened dymanics.effectively volume control level determined by negation of averaged envelope of input level. Early compressors called "Sustain" pedals. Expansion loud sounds louder and soft ones softer. volume control with level determined by averaged of input level. Compression and expansion can complementary, com(pression/ex)panding for noise reduction. Asymmetric compression/peak compression Only peaksget compressed, not the overall level of the waveform envelope. no averaging of envelope and instantaneous waveform level is compressed. a much softer form of clipping, is part of tube sound, since tube with a soft B+ supply are prone to this. Noise gating modulates output off when input level below a threshold. modulation may be square wave, or variation of expansion low level inputs "expanded" down into silence, gives less abrupt transition. Attack delay variation noise gating where transition "on" from "off" or no signal state is slowed. gives output perceptibly rises level each new note envelope, reminiscent of a tape recording played backwards. ADSR Term from synthesizer folks; stands for Attack Decay Sustain Release, most general way to describe a musical envelope. possible to generate artificial ADSR envelope fo musical note to help fool ear which instrument generated Limiting Like compression, operates over some threshold only. keep an input from going over some level, but un-processed below level, as signals on tape without overloading the tape. Example Auto swell rise in level from some starting level to final level when keyed . Can effectively add sustain to some notes and not others , or can add a "swell" in volume over run of notes, or help with presetting level of lead. WAVEFORM DISTORTION EFFECTS Symmetrical clipping tops and bottoms of are clipped equally, symmetrically. generates only odd-order harmonics, giving a reedy, or raspy sound to the resultant waveform. hardness or softness of clipping matters. Hard clipping when output wave equals input up/down to a certain level, then stays at clipping level until input drops below the clipping level again, perfectly flat tops and bottoms to the clipped output. Soft clipping gently rounds the top/bottom of output wave so the waveform is "softly" rounded on top/bottom, not flat-topped. Soft clipping emphasizes lower- order harmonics, the third and fifth, etc. Hard clipping has a mix slewed to higher order seventh up harmonics, which are harsher sounding. Intermodulation distortion, production of sum and difference frequencies from frequencies input waveform, varies with amount and hardness clipping. Intermodulation harsh,ugly. Asymmetrical clipping top(or bottom) clipped more than bottom causes generation of both even and odd harmonics, more asymmetrical, more pronounced the even-order harmonics; harsher clipping, more harmonics are slewed toward higher order Tubes produce asymmetrical distortion unless circuitry set up to remove them, as in push-pull. Infinite limiting waveform is amplified "infinitely" and hard and symmetrically clipped, producing rectangular output only zero crossings with input waveform. Sounds buzzy and synthesizer-ish. Half wave rectification produces prominent second harmonic, heard as an octave. Full wave rectification only second and higher harmonics of original input frequency. very strong octave of the input waveform, a slew of even-, odd-, and intermod- distortion products when more than a single frequency is input ( as is the case for all musical instruments). Arbitrary waveform generation generates a completely new waveform of arbitrary shape which shares same frequency as input waveform. Guitarsynthesizers do a version of this. FILTER/FREQUENCY RESPONSE EFFECTS EQ/tone controls Allow to cut or boost highs, lows, mids etc. Tend to be broad-brush kinds controls - all "high's" raised or cut. Range is typically +/- 12 to 20 db boost/cut. Treble/mid/bass boost like additional eq control, narrower in frequency range, and more boost range, no cut. Cabinet simulation filter designed to mimic two- or four-pole low frequency rolloff of guitar speaker cabinet, to get that "miked cabinet" sound into a PA without really miking cabinet. Resonator filter with boost in frequency at narrow rangefrequencies. sounds like wah pedal when pedal not being moved. Wah resonator that can have its center frequency moved up or down in frequency by moving a pedal. "wah" name mimics moving resonance of human vocal tract in speech as the sound "wah" is made. was originally designed to emulate trumpet using a mute(!). Auto wah "Envelope Follower" wah filter where center frequency determined by loudness of input signal, making moving resonance on every note. Tremolo-wah Wah where center frequency moved back forth cyclically, as though pedal connected to motor or some such. can generate effects similar to rotating speaker or phasing. vibrato" cyclical variation in basic frequency of input signal, similar to moving the whammy bar on suitably equipped guitar. True vibrato as add on effect requires time delay, hard to do until analog digital) delays came to be. Phase shifting a filter response generated by using long phase delays mixing with original signal cause number of deep notches and/or peaks in the overal filter response. mimics larger number of notches and peaks by true time delayed flanging. simple phase shifters or phasers generating two notches, some pedals make four notches.Flangers make many notches. Phasers incorporate feedback to sharpen up effect of notches. TIME DELAY EFFECTS Echo Reverb True vibrato Flanging Slapback Reverse echo/reverb MISCELLANEOUS EFFECTS Octave division Takes fundamental frequency of input signal, divides it by two, and creates an octave-lower, sometimes a two-octave lower signal, which are usually mixed back with original signal. done with digital flipflops to divide signal by two/four after squaring up input to drive flipflops. provides outputs substantially square waves, sounds like fuzz bass. filtering is usually provided to tame the sharp buzz of square waves. simple dividers get very confused when fed more than one tone at once, single note all really practical Harmony generation Generation of other notes at musically-interesting intervals along with your notes. Phase lock tracking a "phase locked loop" can produce an output signal exactly an integer multiple or small-numbers fractions of a reference signal in frequency. generate: signal that follows your notes, perhaps lagging a little with a glide onto note octave or two above a third/fifth/seventh, etc Sounds kind of like a computer playing harmony with you. Noise addition Noise (hiss, rumble, etc) is deliberately added done with restraint and matching input signal envelope can add a breathing effect like the hiss of air in flute. Filtered low frequencies can add growling quality. Talk box effect produced by using small amp to produce sound conducted into your mouth by tube, you can mouth words to song, using your vocal tract resonances to shape instrument sound, which is then picked up by a microphone. This is the archetypical talking guitar". Voice tracking (vocoder) Ring modulation (Double Side Band Suppressed Carrier generation) Single Side Band Suppressed Carrier generation Air Chamber See the term wind chest. Articulate 1. Sight separations made before notes this style playing. organist decides length of separation and which notes to separate. entire technique evolved around this principle a used in playing early organ music Bach and. Handel. 2. Articulate also describe type stop thata clear attack point or chiff. Attack Point moment which pipe begins to speak, when key pressed, isattack point. Different kinds pipes variety of attack points ranging from soft to strong and clear. Bellows older organs, was used to pump air into the reservoir.made of two wedge shaped pieces wood joined by expandable,fan-like leather. Closing bellows forced air into Reservoir. Chiff Pipes that have clear edge to sound described as having "chiff." Any pipe can have chiff but principals always have this clear attack point. Circuit electrical connection which, it magnetizes a piece of metal. involved in the mechanism which opens valves allow pipes to speak in electric action instrument. Combination Action type mechanism which controls work of pistons. One kind of mechanism is digital. Console unit contains everything organist needs to control sound such as manuals, pedalboard, pistons, etc. All together is console. Coupler coupler allows one division connected to another.allows stops of two divisions to controlled by one manual or pedals.the Swell to Great coupler allows Great manual to use stops from Swell.also couplers which act within a division to play stops at different octave. SW 4' is a coupler which play stops in swell up an octave and at regular pitch at t same time. Divisional Piston a piston that affects only one division division on organ have sets pistons that work only on particular division. Division pipes grouped into several separate sections = divisions. Each has nameis controlled through own manual or pedalboard. several manual divisions and most common are: Great, Swell,Choir or Positive. only one Pedal division. Drawknobs turn different kinds of pipe sounds on or off. Pulling knob out turns stop on pushing it in turns it off. builders use stop tabs = flip up down in place drawknobs. Electric Key Action a wire, an electrical circuit and an electro magnet cause valve below each pipe to open and close. When you press the key, you close an electrical contact. electro-magnet to open and close the valves each pipe. Electro-Magnet metal which, when magnetized by an electrical circuit, attracts valve below pipe. valve opens and air flows through pipe, making the pipe speak. Flue Pipe kind of pipe made of metal or wood. sound is produced when wind flows through foot of pipe and flows out mouth (hole in front of pipe). air hits lip of pipe and causes column of air to vibrate. length ofcolumn air which, in turn, determines pitch of sound. pipe's length determines size of air column. For diagram of flue pipe, see sound characteristics page. Most pipes on organ are flue pipes. others are reed pipes. are several types of flue pipes: Principals, Flutes, and Strings. General Piston piston affects entire organ used to recall organist's choice of stops and couplers from all divisions of organ. Key Action mechanism uses to used to control pipe speech. by controlling the air flow to pipes. Legato 1.this style organ playing,notes flow smoothly one to next.Sometimes are breaks between notes for musicalphrases or to accentuate a note, overall effect smooth compared to articulate playing of the Baroque. 2. Legato also refer to technique needed to play notes smoothly. Manuals This is the organ term for the keyboards. Mechanical Action key connected to trackers eventually connect to valves that open to admit air from wind chest into pipe. When press key, are physically opening alve in wind chest. there is one valve for each note on keyboard. if organ has 10 stops, is one valve for all ten pipes which correspond to that note on keyboard. Memory Levels In digitally controlled combination action, a memory level is like a file. Multiple level are essentially multiple files, allowing several different possibilities for one piston. S Pallet or Pallet Valve When air flows to pipe,through hole in wind chest beneath pipe.pallet valve closes this hole when pipe is not used. Pressing key open this valve. Pipe valve is also another term. Pedalboard structure on floor which contains the pedals and which link them to the rest of the organ. Pipe Beard Used only in flue pipes, a metal rod that extends in front of the mouth and connected to ears. Large pipes need this extra piece to focus tone, larger mouth in these pipes makes the tone unstable. Pipe Toe bottom opening of pipe which rests in a hole on top of wind chest. See this page for a diagram of a pipe. Pistons one of numbered thumb buttons or toe studs on console can memorize combination of stops. organist can choose stops to use by turning them on and then set them on one of the numbered pistons. (Most organ consoles have a Set button on the lower left corner of bottom manual used for this purpose.) organist can recall stops at any time by pressing piston. There are general and divisional pistons. Pitch in music is note that sounds. On organ, pitch does not always correspond to key which plays the pitch. Pluck Point the point at which the tracker is pulling the valve open. organist feels this through key. It similar to pluck point in harpsichord, which musician can feel when pressing a key. Principal A principal is one family of sound. is a flue pipe which is rather narrow for its length and produces a bright, clear sound. Rank a row of pipes. row always has all pipes of same kind of sound. all the pipes for a Spitzflute (one kind of flute sound) will be in same row. Organs often described number of ranks they have. 60 rank instrument is large while 18 rank instrument is small. Practice organs from 3 to 9 ranks. Reed Pipe This pipe like single reed orchestral instrument. wind flowing through pipe vibrates metal tongue, strip of flat metal, against an open-faced shallot. not visible from outside because parts are contained in boot, bottom part of pipe which rests on wind chest. sound is amplified by resonator, top, flared part of pipe. Pitch determined by length of tongue. a strong, penetrating tone. Reservoir a storage container for wind. top part of container is expandable, lik accordian. Weights or springs used on expandable part to keep pressure. If wind going to pipes is notconstant pressure, sound will waver and note will warble. Reversibles a convenience item and each one has only one function. Pressing stud reverses what current status of stud was. ifsoff, now on and vice versa. Full Organ which turns on all stops of organ without knobs or tabs moving, Great to Pedal which is foot control of coupler. Roller In mechanical action, keys directly in front of pipes and wind chest so connection between key and valve straight lines and right angles. Sometimes architecture necessitate placing of pipes off to side. Then connection must follow straight lines at irregular angles. roller, a wooden rod,used in this as its rotation can accommodate irregular angles. two arms each end. One attached to key (or pedal) and other attached to valve directly, or trackers which lead to valve. roller mechanism frequently used in pedal division is found in mechanical action instruments. Scaling proportion of width of a pipe to length. Tone quality of the pipe will change as proportion changes. Slider a long wooden slat which has holes in it that correspond to a rows of holes in top of wind chest is used in a slider wind chest (see the next term). Slider Chest type wind chest uses slider to block holes in wind chest and prevent pipes from speaking. Speaking Pipes, Pipe Speech organ slang means the pipe is making a sound. Solid State Combination Action technology allows memory of pistons to be digitally memorized, multiple digital memory banks up to 128 levels, all pistons can be "re-memorized" on multiple levels Staccato notes are played short and detached, they are staccato. Stop knob or tab used to turn sound on or off (see Drawknobs). type of sound available on organ. usually one pipe per note, some kindsuse several pipes for one note on keyboard. Many stops on organ result in tonal color and volume. T several families, or groups, sounds: Reeds, Principals, Flutes, and Strings. Stop Action mechanism turns stops on off through use of drawknobs on sides of console or stop tabs above manuals.turning stop on, barrier between pipes and wind chest moved so air can flow to pipe when its corresponding key pressed. Stop Tabs See Drawknobs. Swell Pedal or Swell Shoe pedal on console controls opening and closing of swell shades. Swell Shades Slatslook like Venetian blinds opened and closed through foot pedal called swell shoe.allows volumecontrol because pipes behind blinds will get louder as shades opened. shades are normally in front o division called swell. also be placed in front of solo and choir divisions if organ has these divisions. Technique in playing instrument refers to all physical movements and mental knowledge needed to play instrument. factual knowledge be taught to anyone. in contrast to artistry, which cannot be taught. Organ repertoire uses two main types of technique: Legato and Articulated Playing. Thumb Pistons below keys of each manual are small buttons. numbered ones are pistons. others have various functions are reversibles thumb used to press is how they got their name. Tone the color of sound. organ a wide variety of sounds available. difference in sound colors of stops makes variety possible. Toe Studs large buttons on console near pedals that control several mechanisms on organ. On right, a group of divisional toe pistons that memorize stops for pedaldivisi group on left general pistons which affect all stops and couplers on organ. are repeats of thumb generals below the manuals,last kind toe studs you are called reversibles. usually spread out across bottom of console, above generals and pedal divisionals. a convenience item and has only one function per stud. Tracker Another name for mechanical action. also a long thin piece of wood used in mechanical action instruments to open valve (See next term). Valve open or close to admit air to the pipe. Their movement is controlled through keys on keyboard. key down pulls valve open. Each key has spring underneath so key returns to "up" position, allowing valve to close. Voicing, Voiced All pipes in organ are altered after organ installed acoustics room affect organ's sound. Tonal color, volume, stability of sound affected by alterations. For example, an unusually loud pipe that sticks out above rest is softened until volume matches other pipes of that stop. Pipe organs intentionally voiced Each note will sound slightly different in character, an overall volume increase as notes go up scale. Wind Chest pipes sit atop this plain wooden box. stop on, air flows from reservoir into box. When notes are played, uses air from this box to make the pipes speak.