When you hear a musical sound, let's say at 500 Hz, you are also hearing related sounds at 1 kHz, 1.5 kHz, 2.0 kHz and so on until the energy level of the frequency drops off.  Understanding harmonics will help you identify related frequencies and control your sound system's output accordingly.  Find out how...  read more »

"Is there a difference between volume and decibel level?"

Volume is not a well-defined measure of sound.  Decibel is defined...as a ratio.

If you have two audio signals, and one is a ten times stronger than the other, you can say it is 10dB stronger. If it is 100x stronger it is 20dB, if it is 100x weaker, it is -20dB. It's a logarithmic formula.

Sound pressure levels (SPL) given in dB refer to 20microPascal at 0dB, which is actually around the threshold level of hearing anything at all.  read more »

The one instrument that will tell you if you really are too loud.  read more »

The folks at NASA, who have studied sound frequencies longer than I've been alive, have produced this easy-to-read (a lot of easy to understand pictures) pdf ebook on "Vibration Control Principles."  It's all good information.  Pay particular attention to pages 52 and 54-58.  You can grab it here.

Sound is what you hear. I hope you aren't satisfied with that answer. A sound engineer needs to understand not only what they hear, but what happens with sound.

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