Sound level SPL, pressure, pascal, and intensity level (SIL) conversion 
Speed of sound in air and the significant temperature calculation 
Table of sound pressure levels − Sound pressure and intensity 
Speed of sound (velocity of sound) in humid air calculation 
Microphone sensitivity conversion dB re 1 V/Pa − Transfer factor mV/Pa 
Speed of sound, the temperature, and not the air pressure 
Voltage (volt) to level dBu and dBV conversion and vice versa 
Temperature dependence of acoustic quantities 
Sound pressure, particle velocity, impedance, sound intensity calculation 
Room modes calculation − Axial, tangential, and oblique modes 
Electrical voltage, current, resistance, and power calculation 
Standing waves on a string and room modes between parallel walls 
Formula Wheel of Acoustics − Most important Formulas 
Room modes − Standing waves in air − Bass reflections at walls 
Formula Wheel of Electro Engineering − Most important formulas 
Room modes and vibrations of strings compared  Standing waves 
Frequency ratio (interval) to cents conversion and vice versa 
Comb filters − Dips and peaks − Delay time and Interference (ITDG) 
Period, cycle duration, periodic time to frequency calculation 
Bandwidth in octaves to Q factor (filter) conversion and vice versa 
All 15 overtones (harmonics) from fundamental frequency calculation 
Q Factor and filter center frequency − Find −3 dB cutoff frequencies 
The decibel calculator (dB) − A valuable tool 
Filter slope or steepness (dB/oct) is really not bandwidth 
Thermal noise calculation − Johnson noise − White noise calculator 
Voltage V to dBu, dBV, and dBm − power level dBm calculator 
Time constant and cutoff frequency conversion − Equalization (EQ filter) 
Reverb time RT60 after Sabine calculation − room acoustic parameter 
RC filter cutoff frequency and time constant calculation 
Reverberation time RT60 to Sound decay rate conversion 
Adding decibels − Combining up to ten (10) acoustic levels 
Absorption coefficients of building materials and finishes 
Adding decibels − Combining up to thirty (30) sound levels 
Degrees Celsius and Fahrenheit − Temperature comparison 
Sones and phons loudness conversion and the problem with dBA 
Measurement of input impedance and output impedance 
● Interconnection of two audio units − Voltage bridging − Zout < Zin 
ALcons and STI speech − Intelligibility conversion 
Levels in decibels and references of sound quantities − Calculation 
XLC reactance calculator with frequency 
● Total level in decibels − Adding of incoherent sound sources 
Voltage divider calculation − Opencircuit and loaded circuit 
● Total level in decibels − Adding of coherent electrical signals 
Voltage divider calculation − Unloaded (voltage drop) 
Geometric mean − Arithmetic mean − Calculation of the center frequency 
Pressure units − Calculation and conversion 
● Sound and distance − Sound pressure and sound intensity 
Frequency domain of musical instruments, voices (vocals), and keyboards 
● Damping (decrease) of sound level with distance r (noise propagation) 
Magnetic flux in nWb per meter and conversion to flux level in dB 
Time difference Δ t and sound path d distance conversion 
Relationship of acoustic quantities − Plane progressive sound wave 
Frequency to wavelength conversion and vice versa (sound and light) 
Bits and bytes conversion − Kibibits and other prefixes 
Wavelength of an acoustic wave in air calculation (sound waves) 
Resistor color code calculator − Values with 4 or 5 color bands 
Bel to decibel conversion and more ... (Level Prefixes Conversion) 
Data transfer rate units conversion − Bits per second = bps 
● Factor, ratio, gain to a level value conversion (Gain, decibels, dB) 
Air damping formulae (High frequencies / Dissipation) calculation 
Amplification (gain) and damping (loss) in dB − Computation 
Extension angle of the orchestra calculation (microphone position) 
Decibels to voltage gain / loss conversion − Amplification / damping 
FletcherMunson is not RobinsonDadson − ISO 226:2003 
Decibel (dB) calculation − Amplification and damping − Gain and loss 
Unit conversion table − Conversion of units 
dB chart for voltages and powers − Relative level and absolute level 
Nepers to decibels conversion and vice versa 
Voltage and power gain calculation 
L pad for loudspeaker damping calculation − Voltage divider 
Capacitive reactance calculator XC (Condenser Capacity) 
Crosssectional area to diameter for round wires and cables 
Amplitude sum in dB (voltage) and power sum calculation 
Cable length, cable capacity, and the cutoff frequency calculation 
Phase angle, time delay, and frequency calculation 
Why does proximity effect occur? − Shure Pro Audio 
Normal equalloudness level contours from 2003 (new) 
Direction of phantom sources by calculation of Δ L and Δ t 
gif file: ISO 226:2003 − Normal equalloudness contours (new) 
● Compare sound power and sound pressure in a distance 
Ohm's law − Magic triangle − Calculator and formulae 
Tony Faulkner's parallel AB figureofeight microphone pair 
Loudspeaker sensitivity to efficiency in percent conversion 
Tony Faulkner's Phased Array microphone system − Review 
Pitch change by temperature change (variation)  wind instruments 
Formula symbols of electrical engineering and electroacoustics 
International Level Displays dBu − Digital + analog 
Active Audio Filter − Low cut, high cut, and bandpass 
Distortion attenuation dB to THD factor in percent conversion 
Absorption of sound by the atmosphere calculation 
Sound pressure and the inverse distance law 1/r 
Direction of the phantom sources by Δ L and Δ t calculation 
Sound intensity and the inverse square law 1/r² 
Phantom image sources − Stereo loudspeaker signals 1 
Number relations (ratio) to decibel (dB) level conversion 
Phantom image sources − Stereo loudspeaker signals 2 
Parallel resistance calculator − Find the parallel resistance 
How do Sound Pressure Levels (SPL) add when listening? 
Resistor pairs − Reverse engineered calculator 
Inches and centimeters in comparison − Metric and inch ruler 
Comparative representation of basic acoustic quantities − Formulas 
Visualization of microphone systems − SRA calc of Δ L and Δ t 
Relationships of acoustic quantities 
SRA calculation of Δ L and Δ t for stereo microphone arrays − flash 
Tuning keyboard frequencies and notes − English and German 
Decrease in level of sound pressure and sound intensity with distance 
Chord name finder by note name entry − Chord recognition 
Active AudioFilter calculation (Low cut − High cut − Bandpass) 
Weighting filter calculation − Weighted dBA and dBC − Frequency 
Terms of audio engineering and acoustics − English and German 
● Amplifier, loudspeaker, and ohms − The misunderstood topic 
dB dBu dBV − Comparison table for PPM and VU meters 
● Loudness/Volume − Sound level definition and the change of factors 
Damping of bridging and damping factor calculation in audio 
● Sound pressure and Sound power – Effect and Cause 
Celsius (°C), Fahrenheit (°F), Kelvin, and °Reaumur − Formulas 
Radio frequency to wavelength conversion and vice versa 
Sound pressure level SPL and permissible exposure time for noise 
gif File: Various microphone connectors (plugs) – Sennheiser MD421 
Wave graphs calculation − Amplitude, distance and time 
Vowel diagram − First two formant frequencies as triangle − htm 
Jecklin disc (new) − A stereo microphone array with isolating baffle 
gif file: Vowel diagram or vowel triangle − The first two frequencies 
Trygg Tryggvason: The Decca Tree − Classical Sound Recording 
● The human perception of loudness − Loudness factor gain ratio 
Direct field D (Free field) and Reverberant field R (Diffuse field) 
Combine levels of onethird octave bands to octave band 
David Griesinger − Man behind reverb algorithms 
Pressure gradient and phase − M/S signal − omnidirectional pattern 
Sengpiel − Mentioned in papers of the AES (Audio Engineering Society) 
EBS Stereo Microphone System − Equivalence Stereophony 
BPM tempo and delay to time and frequency − Conversion chart 
"Live End − Dead End" − Thoughts about the Reflexion Filter 
BPM − Beats per minute counter and calculator 
"Kaotica Eyeball" − Singing into a bucket 
Sound pressure conversion direct to Sound intensity and vice versa 
Questions to sound waves and the amplitudes − Right answers 
Surprise − Sound does not come from the strings 
Adding amplitudes and levels − Coherent and incoherent signals 
8 Ohm Output and 150 Ohm Input − What is that? 
What is amplitude? Which amplitude exactly? 
Two Different Boundary MicrophoneTypes − Crown PZM 
● Many Amplitudes − Sound field quantities of a plane wave 
Sound Sound Sound − pressure − sound intensity − acoustic impedance 
Musical Terms  Music Glossary Terminology Words (English/German) 



Length m, cm, inch, feet and yard − Ruler cm to inch conversion 
English and American measures to metric conversions 
Temperature °F, °C, K, °Rankine and °Reaumur conversion 
Weight conversion milligram to kilogram and liter 
Formula symbols of electrical engineering and electroacoustics 
Volume conversion milliliter to liter and kilogram 
Measurement Unit Conversions − Unit conversion calculator 
Time conversion millisecond and second 
Body length and height (size) calculation footinch to cm and vice versa 
Length conversion millimeter and meter 
Quadratic equation solver 
Prefixes conversion Temperature unit conversion 
Time addition calculator − Add time together 
Length unit conversion Time Unit conversion 
Is this a prime number? 
Area unit conversion Energy unit conversion 
How to calculate logarithms? 
Volume unit conversion Power unit conversion 
Unit conversion table − Conversion of units 
WeightMass unit conversion Density unit conversion 
Alphabetical list of conversion factors 
Pressure unit conversion Acceleration unit conversion 
SI derived units (SI based units) 
Force unit conversion Velocity or Speed unit conversion 
Decibel (dB) to percentage (%) converter − THD Total Harmonic Distortion 


● Go to German audio technology calculations 1 

● Go to German temperature, length, and weight calculations 2 
→ → → → → → → → → → → 
prefixes  length  area  volume  weight  pressure  temperature  time 
energy  power  density  velocity  acceleration  force 

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Positive input, errors, or criticism of my websites − please mail to: 
Go to German area calculations and shape calculations 3 
→ → → eberhard "at" sengpielaudio.com 
● List of some CD recordings ● List of some recorded artists 



