SOUND FREQUENCY WAVE LENGTH

SOUND FREQUENCY WAVE LENGTH

SOUND FREQUENCY WAVE LENGTH

By: Don McClatchie

All signals both RF and Audio are electromagnetic waves that travel down wires or through the air and they all have a wavelength. The wavelength of any frequency is the distance any frequency travels in the time of one cycle. The distance that the any signal travels through the air in one cycles time is directly related to the frequency of the signal, but also to a lesser degree other factors like the gas composition of the air, air temperature, air pressure, and moisture in the air. Basically, anything that changes the density of the air will affect the time it takes for one cycle to go the distance.

The following sound frequency wavelength chart lists frequencies from 1 Hz that lists the speed of sound in the air at 68 Degrees as 1128.608924 feet per second, and the speed of sound in the air at 95 Degrees with water vapor. You can see how water vapor effects the speed and so the wavelength.  The table lists many frequencies from 1 Hz to 100 KHz with many octaves of audio notes also TV and FM radio Pilots are marked in the Notes.

When placing microphones or speakers for recording and listening these distances should be avoided because the wavelength will cause subtractions and additions by interaction with the wavelength of any frequency. Particularly the 1/2 wavelength will cause cancellations of certain frequencies while re-enforcing others. Refection distances should be considered when placing microphones in recording studios and other venues.

A test can be made by using a tone generator output to speakers and monitoring the audio of a single frequency at a time. Slowly sweep through the audio spectrum and measure the microphone level for any level changes that would indicate at what frequencies if any a problem exists.

Every recording studio has its own sound created by the wavelength effect. Studio engineers work very hard at eliminating these audio anomalies but as you can see by the table it is a difficult thing to accomplish.

If you wish to know the wavelength of any other material, simply divide the speed of sound in feet per second through that material by the frequency in cycles and you have your answer.

 SOUND FREQUENCY WAVE LENGTH The speed of sound is relative to the material it is moving through and the temperature of the material. When placing speakers and microphones you should avoid placing them at these precise distances apart. Through Dry Air at 68 Degrees F Through Water Vapor at 95 Degrees F Frequency Wave Length 1/2 Length 1/4 Length Wave Length 1/2 Length 1/4 Length NOTES: in Hertz in Feet in Feet in Feet in Feet in Feet in Feet 1 1128.6089240 564.3044620 282.1522310 1318.8976380 659.4488190 329.7244095 2 564.3044620 282.1522310 141.0761155 659.4488190 329.7244095 164.8622048 3 376.2029747 188.1014873 94.0507437 439.6325460 219.8162730 109.9081365 4 282.1522310 141.0761155 70.5380578 329.7244095 164.8622048 82.4311024 5 225.7217848 112.8608924 56.4304462 263.7795276 131.8897638 65.9448819 6 188.1014873 94.0507437 47.0253718 219.8162730 109.9081365 54.9540683 7 161.2298463 80.6149231 40.3074616 188.4139483 94.2069741 47.1034871 8 141.0761155 70.5380578 35.2690289 164.8622048 82.4311024 41.2155512 9 125.4009916 62.7004958 31.3502479 146.5441820 73.2720910 36.6360455 10 112.8608924 56.4304462 28.2152231 131.8897638 65.9448819 32.9724410 16.35 69.0280687 34.5140344 17.2570172 80.6665222 40.3332611 20.1666306 C  OCTAVE 0 17.32 65.1621781 32.5810890 16.2905445 76.1488244 38.0744122 19.0372061 C#  OCTAVE 0 18.35 61.5045735 30.7522868 15.3761434 71.8745307 35.9372653 17.9686327 D    OCTAVE 0 19.45 58.0261658 29.0130829 14.5065414 67.8096472 33.9048236 16.9524118 D#  OCTAVE 0 20 56.4304462 28.2152231 14.1076116 65.9448819 32.9724410 16.4862205 20.6 54.7868410 27.3934205 13.6967102 64.0241572 32.0120786 16.0060393 E    OCTAVE 0 21.83 51.6999049 25.8499525 12.9249762 60.4167493 30.2083747 15.1041873 F    OCTAVE 0 23.12 48.8152649 24.4076324 12.2038162 57.0457456 28.5228728 14.2614364 F#  OCTAVE 0 24.5 46.0656704 23.0328352 11.5164176 53.8325567 26.9162783 13.4581392 G    OCTAVE 0 25.96 43.4749200 21.7374600 10.8687300 50.8049938 25.4024969 12.7012484 G#  OCTAVE 0 27.5 41.0403245 20.5201623 10.2600811 47.9599141 23.9799571 11.9899785 A    OCTAVE 0 29.14 38.7305739 19.3652870 9.6826435 45.2607288 22.6303644 11.3151822 A#   OCTAVE 0 30 37.6202975 18.8101487 9.4050744 43.9632546 21.9816273 10.9908137 30.87 36.5600558 18.2800279 9.1400140 42.7242513 21.3621257 10.6810628 B    OCTAVE 0 32.7 34.5140344 17.2570172 8.6285086 40.3332611 20.1666306 10.0833153 C    OCTAVE 1 34.65 32.5716861 16.2858431 8.1429215 38.0634239 19.0317119 9.5158560 C#  OCTAVE 1 36.71 30.7439097 15.3719548 7.6859774 35.9274758 17.9637379 8.9818690 D    OCTAVE 1 38.89 29.0205432 14.5102716 7.2551358 33.9135417 16.9567709 8.4783854 D#  OCTAVE 1 40 28.2152231 14.1076116 7.0538058 32.9724410 16.4862205 8.2431102 41.2 27.3934205 13.6967102 6.8483551 32.0120786 16.0060393 8.0030196 E    OCTAVE 1 43.65 25.8558745 12.9279373 6.4639686 30.2152953 15.1076476 7.5538238 F    OCTAVE 1 46.25 24.4023551 12.2011776 6.1005888 28.5167057 14.2583528 7.1291764 F#  OCTAVE 1 49 23.0328352 11.5164176 5.7582088 26.9162783 13.4581392 6.7290696 G   OCTAVE 1 50 22.5721785 11.2860892 5.6430446 26.3779528 13.1889764 6.5944882 51.91 21.7416475 10.8708238 5.4354119 25.4073904 12.7036952 6.3518476 G#  OCTAVE 1 55 20.5201623 10.2600811 5.1300406 23.9799571 11.9899785 5.9949893 A    OCTAVE 1 58.27 19.3686103 9.6843052 4.8421526 22.6342481 11.3171241 5.6585620 A#   OCTAVE 1 60 18.8101487 9.4050744 4.7025372 21.9816273 10.9908137 5.4954068 LINE RATE 61.74 18.2800279 9.1400140 4.5700070 21.3621257 10.6810628 5.3405314 B    OCTAVE 1 65.41 17.2543789 8.6271895 4.3135947 20.1635474 10.0817737 5.0408869 C    OCTAVE 2 69.3 16.2858431 8.1429215 4.0714608 19.0317119 9.5158560 4.7579280 C#  OCTAVE 2 Frequency Wave Length 1/2 Length 1/4 Length Wave Length 1/2 Length 1/4 Length NOTES: in Hertz in Feet in Feet in Feet in Feet in Feet in Feet Frequency Wave Length 1/2 Length 1/4 Length Wave Length 1/2 Length 1/4 Length NOTES: in Hertz in Feet in Feet in Feet in Feet in Feet in Feet 70 16.1229846 8.0614923 4.0307462 18.8413948 9.4206974 4.7103487 73.42 15.3719548 7.6859774 3.8429887 17.9637379 8.9818690 4.4909345 D    OCTAVE 2 77.78 14.5102716 7.2551358 3.6275679 16.9567709 8.4783854 4.2391927 D#  OCTAVE 2 80 14.1076116 7.0538058 3.5269029 16.4862205 8.2431102 4.1215551 82.41 13.6950482 6.8475241 3.4237621 16.0040971 8.0020485 4.0010243 E    OCTAVE 2 87.31 12.9264566 6.4632283 3.2316141 15.1059173 7.5529586 3.7764793 F  OCTAVE 2 90 12.5400992 6.2700496 3.1350248 14.6544182 7.3272091 3.6636046 92.5 12.2011776 6.1005888 3.0502944 14.2583528 7.1291764 3.5645882 F#  OCTAVE 2 98 11.5164176 5.7582088 2.8791044 13.4581392 6.7290696 3.3645348 G    OCTAVE 2 100 11.2860892 5.6430446 2.8215223 13.1889764 6.5944882 3.2972441 103.83 10.8697768 5.4348884 2.7174442 12.7024717 6.3512359 3.1756179 G#  OCTAVE 2 110 10.2600811 5.1300406 2.5650203 11.9899785 5.9949893 2.9974946 A    OCTAVE 2 116.54 9.6843052 4.8421526 2.4210763 11.3171241 5.6585620 2.8292810 A#   OCTAVE 2 123.47 9.1407542 4.5703771 2.2851886 10.6819279 5.3409640 2.6704820 B    OCTAVE 2 130.81 8.6278490 4.3139245 2.1569622 10.0825444 5.0412722 2.5206361 C    OCTAVE 3 138.59 8.1435091 4.0717545 2.0358773 9.5165426 4.7582713 2.3791356 C#   OCTAVE 3 146.83 7.6865009 3.8432504 1.9216252 8.9824807 4.4912403 2.2456202 D    OCTAVE 3 155.56 7.2551358 3.6275679 1.8137839 8.4783854 4.2391927 2.1195964 D#   OCTAVE 3 164.81 6.8479396 3.4239698 1.7119849 8.0025341 4.0012670 2.0006335 E    OCTAVE 3 174.61 6.4635984 3.2317992 1.6158996 7.5533912 3.7766956 1.8883478 F    OCTAVE 3 185 6.1005888 3.0502944 1.5251472 7.1291764 3.5645882 1.7822941 F#   OCTAVE 3 196 5.7582088 2.8791044 1.4395522 6.7290696 3.3645348 1.6822674 G    OCTAVE 3 200 5.6430446 2.8215223 1.4107612 6.5944882 3.2972441 1.6486220 207.65 5.4351501 2.7175751 1.3587875 6.3515417 3.1757709 1.5878854 G#   OCTAVE 3 220 5.1300406 2.5650203 1.2825101 5.9949893 2.9974946 1.4987473 A    OCTAVE 3 233.08 4.8421526 2.4210763 1.2105381 5.6585620 2.8292810 1.4146405 A#   OCTAVE 3 246.97 4.5698219 2.2849110 1.1424555 5.3403152 2.6701576 1.3350788 B    OCTAVE 3 261.63 4.3137596 2.1568798 1.0784399 5.0410795 2.5205398 1.2602699 C    OCTAVE 4 277.18 4.0717545 2.0358773 1.0179386 4.7582713 2.3791356 1.1895678 C#   OCTAVE 4 293.66 3.8432504 1.9216252 0.9608126 4.4912403 2.2456202 1.1228101 D    OCTAVE 4 300 3.7620297 1.8810149 0.9405074 4.3963255 2.1981627 1.0990814 311.13 3.6274513 1.8137257 0.9068628 4.2390565 2.1195282 1.0597641 D#   OCTAVE 4 329.63 3.4238659 1.7119330 0.8559665 4.0011456 2.0005728 1.0002864 E    OCTAVE 4 349.23 3.2317067 1.6158533 0.8079267 3.7765875 1.8882937 0.9441469 F    OCTAVE 4 369.99 3.0503768 1.5251884 0.7625942 3.5646846 1.7823423 0.8911711 F#   OCTAVE 4 392 2.8791044 1.4395522 0.7197761 3.3645348 1.6822674 0.8411337 G    OCTAVE 4 400 2.8215223 1.4107612 0.7053806 3.2972441 1.6486220 0.8243110 415.3 2.7175751 1.3587875 0.6793938 3.1757709 1.5878854 0.7939427 G#   OCTAVE 4 440 2.5650203 1.2825101 0.6412551 2.9974946 1.4987473 0.7493737 A    OCTAVE 4 466.16 2.4210763 1.2105381 0.6052691 2.8292810 1.4146405 0.7073203 A#   OCTAVE 4 493.88 2.2851886 1.1425943 0.5712971 2.6704820 1.3352410 0.6676205 B    OCTAVE 4 500 2.2572178 1.1286089 0.5643045 2.6377953 1.3188976 0.6594488 523.25 2.1569210 1.0784605 0.5392303 2.5205879 1.2602940 0.6301470 C    OCTAVE 5 554.37 2.0358405 1.0179203 0.5089601 2.3790927 1.1895464 0.5947732 C#   OCTAVE 5 587.33 1.9215925 0.9607963 0.4803981 2.2455819 1.1227910 0.5613955 D    OCTAVE 5 600 1.8810149 0.9405074 0.4702537 2.1981627 1.0990814 0.5495407 Frequency Wave Length 1/2 Length 1/4 Length Wave Length 1/2 Length 1/4 Length NOTES: in Hertz in Feet in Feet in Feet in Feet in Feet in Feet Frequency Wave Length 1/2 Length 1/4 Length Wave Length 1/2 Length 1/4 Length NOTES: in Hertz in Feet in Feet in Feet in Feet in Feet in Feet 622.25 1.8137548 0.9068774 0.4534387 2.1195623 1.0597811 0.5298906 D#   OCTAVE 5 659.26 1.7119330 0.8559665 0.4279832 2.0005728 1.0002864 0.5001432 E    OCTAVE 5 698.46 1.6158533 0.8079267 0.4039633 1.8882937 0.9441469 0.4720734 F    OCTAVE 5 700 1.6122985 0.8061492 0.4030746 1.8841395 0.9420697 0.4710349 739.99 1.5251678 0.7625839 0.3812920 1.7823182 0.8911591 0.4455795 F#   OCTAVE 5 783.99 1.4395706 0.7197853 0.3598926 1.6822889 0.8411444 0.4205722 G    OCTAVE 5 800 1.4107612 0.7053806 0.3526903 1.6486220 0.8243110 0.4121555 830.61 1.3587712 0.6793856 0.3396928 1.5878663 0.7939332 0.3969666 G#   OCTAVE 5 880 1.2825101 0.6412551 0.3206275 1.4987473 0.7493737 0.3746868 A    OCTAVE 5 900 1.2540099 0.6270050 0.3135025 1.4654418 0.7327209 0.3663605 932.33 1.2105252 0.6052626 0.3026313 1.4146253 0.7073127 0.3536563 A#   OCTAVE 5 987.77 1.1425827 0.5712914 0.2856457 1.3352275 0.6676137 0.3338069 B    OCTAVE 5 1000 1.1286089 0.5643045 0.2821522 1.3188976 0.6594488 0.3297244 1046.5 1.0784605 0.5392303 0.2696151 1.2602940 0.6301470 0.3150735 C    OCTAVE 6 1108.73 1.0179295 0.5089647 0.2544824 1.1895571 0.5947785 0.2973893 C#   OCTAVE 6 1174.66 0.9607963 0.4803981 0.2401991 1.1227910 0.5613955 0.2806977 D    OCTAVE 6 1244.51 0.9068701 0.4534351 0.2267175 1.0597726 0.5298863 0.2649432 D#   OCTAVE 6 1318.51 0.8559730 0.4279865 0.2139932 1.0002940 0.5001470 0.2500735 E    OCTAVE 6 1396.91 0.8079325 0.4039662 0.2019831 0.9441536 0.4720768 0.2360384 F    OCTAVE 6 1479.98 0.7625839 0.3812920 0.1906460 0.8911591 0.4455795 0.2227898 F#   OCTAVE 6 1567.98 0.7197853 0.3598926 0.1799463 0.8411444 0.4205722 0.2102861 G    OCTAVE 6 1661.22 0.6793856 0.3396928 0.1698464 0.7939332 0.3969666 0.1984833 G#   OCTAVE 6 1760 0.6412551 0.3206275 0.1603138 0.7493737 0.3746868 0.1873434 A    OCTAVE 6 1864.66 0.6052626 0.3026313 0.1513156 0.7073127 0.3536563 0.1768282 A#   OCTAVE 6 1975.53 0.5712942 0.2856471 0.1428236 0.6676171 0.3338086 0.1669043 B    OCTAVE 6 2000 0.5643045 0.2821522 0.1410761 0.6594488 0.3297244 0.1648622 2093 0.5392303 0.2696151 0.1348076 0.6301470 0.3150735 0.1575367 C    OCTAVE 7 2217.46 0.5089647 0.2544824 0.1272412 0.5947785 0.2973893 0.1486946 C#   OCTAVE 7 2349.32 0.4803981 0.2401991 0.1200995 0.5613955 0.2806977 0.1403489 D    OCTAVE 7 2489.02 0.4534351 0.2267175 0.1133588 0.5298863 0.2649432 0.1324716 D#   OCTAVE 7 2637.02 0.4279865 0.2139932 0.1069966 0.5001470 0.2500735 0.1250367 E    OCTAVE 7 2793.83 0.4039648 0.2019824 0.1009912 0.4720751 0.2360376 0.1180188 F    OCTAVE 7 2959.96 0.3812920 0.1906460 0.0953230 0.4455795 0.2227898 0.1113949 F#   OCTAVE 7 3000 0.3762030 0.1881015 0.0940507 0.4396325 0.2198163 0.1099081 3135.96 0.3598926 0.1799463 0.0899732 0.4205722 0.2102861 0.1051431 G    OCTAVE 7 3322.44 0.3396928 0.1698464 0.0849232 0.3969666 0.1984833 0.0992416 G#   OCTAVE 7 3520 0.3206275 0.1603138 0.0801569 0.3746868 0.1873434 0.0936717 A    OCTAVE 7 3729.31 0.3026321 0.1513161 0.0756580 0.3536573 0.1768286 0.0884143 A#   OCTAVE 7 3951.07 0.2856464 0.1428232 0.0714116 0.3338077 0.1669039 0.0834519 B    OCTAVE 7 4000 0.2821522 0.1410761 0.0705381 0.3297244 0.1648622 0.0824311 4186.01 0.2696145 0.1348072 0.0674036 0.3150727 0.1575364 0.0787682 C    OCTAVE 8 4434.92 0.2544824 0.1272412 0.0636206 0.2973893 0.1486946 0.0743473 C#   OCTAVE 8 4698.64 0.2401991 0.1200995 0.0600498 0.2806977 0.1403489 0.0701744 D    OCTAVE 8 4978.03 0.2267180 0.1133590 0.0566795 0.2649437 0.1324718 0.0662359 D#   OCTAVE 8 5000 0.2257218 0.1128609 0.0564304 0.2637795 0.1318898 0.0659449 5274.04 0.2139932 0.1069966 0.0534983 0.2500735 0.1250367 0.0625184 E    OCTAVE 8 Frequency Wave Length 1/2 Length 1/4 Length Wave Length 1/2 Length 1/4 Length NOTES: in Hertz in Feet in Feet in Feet in Feet in Feet in Feet Frequency Wave Length 1/2 Length 1/4 Length Wave Length 1/2 Length 1/4 Length NOTES: in Hertz in Feet in Feet in Feet in Feet in Feet in Feet 5587.65 0.2019828 0.1009914 0.0504957 0.2360380 0.1180190 0.0590095 F    OCTAVE 8 5919.91 0.1906463 0.0953231 0.0476616 0.2227902 0.1113951 0.0556975 F#   OCTAVE 8 6000 0.1881015 0.0940507 0.0470254 0.2198163 0.1099081 0.0549541 6271.93 0.1799460 0.0899730 0.0449865 0.2102858 0.1051429 0.0525714 G    OCTAVE 8 6644.88 0.1698464 0.0849232 0.0424616 0.1984833 0.0992416 0.0496208 G#   OCTAVE 8 7000 0.1612298 0.0806149 0.0403075 0.1884139 0.0942070 0.0471035 7040 0.1603138 0.0801569 0.0400784 0.1873434 0.0936717 0.0468359 A    OCTAVE 8 7458.62 0.1513161 0.0756580 0.0378290 0.1768286 0.0884143 0.0442072 A#   OCTAVE 8 7902.13 0.1428234 0.0714117 0.0357058 0.1669041 0.0834520 0.0417260 B    OCTAVE 8 8000 0.1410761 0.0705381 0.0352690 0.1648622 0.0824311 0.0412156 9000 0.1254010 0.0627005 0.0313502 0.1465442 0.0732721 0.0366360 10000 0.1128609 0.0564304 0.0282152 0.1318898 0.0659449 0.0329724 11000 0.1026008 0.0513004 0.0256502 0.1198998 0.0599499 0.0299749 12000 0.0940507 0.0470254 0.0235127 0.1099081 0.0549541 0.0274770 13000 0.0868161 0.0434080 0.0217040 0.1014537 0.0507268 0.0253634 14000 0.0806149 0.0403075 0.0201537 0.0942070 0.0471035 0.0235517 15000 0.0752406 0.0376203 0.0188101 0.0879265 0.0439633 0.0219816 15734 0.0717306 0.0358653 0.0179326 0.0838247 0.0419123 0.0209562 TV ST PILOT 16000 0.0705381 0.0352690 0.0176345 0.0824311 0.0412156 0.0206078 17000 0.0663888 0.0331944 0.0165972 0.0775822 0.0387911 0.0193956 18000 0.0627005 0.0313502 0.0156751 0.0732721 0.0366360 0.0183180 19000 0.0594005 0.0297002 0.0148501 0.0694157 0.0347078 0.0173539 FM ST PILOT 20000 0.0564304 0.0282152 0.0141076 0.0659449 0.0329724 0.0164862 21000 0.0537433 0.0268716 0.0134358 0.0628046 0.0314023 0.0157012 22000 0.0513004 0.0256502 0.0128251 0.0599499 0.0299749 0.0149875 23000 0.0490700 0.0245350 0.0122675 0.0573434 0.0286717 0.0143358 24000 0.0470254 0.0235127 0.0117563 0.0549541 0.0274770 0.0137385 25000 0.0451444 0.0225722 0.0112861 0.0527559 0.0263780 0.0131890 26000 0.0434080 0.0217040 0.0108520 0.0507268 0.0253634 0.0126817 27000 0.0418003 0.0209002 0.0104501 0.0488481 0.0244240 0.0122120 28000 0.0403075 0.0201537 0.0100769 0.0471035 0.0235517 0.0117759 29000 0.0389175 0.0194588 0.0097294 0.0454792 0.0227396 0.0113698 30000 0.0376203 0.0188101 0.0094051 0.0439633 0.0219816 0.0109908 40000 0.0282152 0.0141076 0.0070538 0.0329724 0.0164862 0.0082431 50000 0.0225722 0.0112861 0.0056430 0.0263780 0.0131890 0.0065945 60000 0.0188101 0.0094051 0.0047025 0.0219816 0.0109908 0.0054954 70000 0.0161230 0.0080615 0.0040307 0.0188414 0.0094207 0.0047103 80000 0.0141076 0.0070538 0.0035269 0.0164862 0.0082431 0.0041216 90000 0.0125401 0.0062700 0.0031350 0.0146544 0.0073272 0.0036636 100000 0.0112861 0.0056430 0.0028215 0.0131890 0.0065945 0.0032972 Frequency Wave Length 1/2 Length 1/4 Length Wave Length 1/2 Length 1/4 Length in Hertz in Feet in Feet in Feet in Feet in Feet in Feet Through Dry Air at 68 Degrees F Through Water Vapor at 95 Degrees F