----- FREQ. RESPONSE RANGE OF SOUND REPROD.
Average Quality Hi Fi
Bus speaker Average Quality in enclosure
Bass speaker Finest Quality in suitable enclosure Domestic Quality Record Player Domestic Quality Tape Recorder Earliest Gramophone with sound box Electrostatic Wide Range Speaker Finest HI FI Equipment High Quality Magnetic Recording Tape High Quality Tape Recorder Human voice adult speech Inexpensive Transistor Set LP 33.3 r.p.m. record Middle Range Speaker Normal AM Table Radio Percussion Instruments Portable Transistor Set High Quality Range of Human Hearing String Instruments Telephone Tone Control Bass Range Tone Control Presence Range Tone Control for Rumble Filter Tone Control Treble Range Tweeter High Quality Tweeter Inexpensive Grade Wind Instruments
---------- DECIBELS AND POWER RATIO--RELATIONSHIP POWER RATIO DECIBELS
---------- TYPICAL LOUDNESS LEVELS LEVEL IN dB
Threshold of audibility Quiet whisper Studio noise level Quiet room in house Suburban street Noise in large office Quiet speech (close proximity) Noise in restaurant Conversation (close proximity) Factory noise Grand Plano Noise in underground train Symphony orchestra Threshold of feeling Threshold of pain
------------- FREQUENCY
Piano scale showing the frequencies to which the keys are usually tuned, which is to a slightly different pitch from that used by physicists, based on Middle C = 256 c/s., and such scales are apt to be misleading. Frequencies of black keys Can be obtained by multiplying the frequency of the white key below it by 1.05946. This scale is useful for the approximate calibration of oscillators and rough determination of resonant frequencies, etc.
--- Speaker Impedance in ohms and Power Distribution Percentage
------ Speaker Impedance in ohms and Power Distribution Percentage.