# What is the effect of increasing frequency on the sound wave?

If I keep the amplitude constant and up the frequency of the sound wave, what effect does just the frequency have on the quality of the sound with regard to human hearing?

Does the sound become shriller in tone?

• To be technically correct - only sine waves are made of a single frequency; all other sounds are made of more than one. Thus, you can't really 'increase' the frequency of a sound wave. You pitch-shift it. Nov 28, 2013 at 1:46
• Thank you, @Izhaki. Can you tell me how you learnt all this? What's a good place to start? Is there a book that you found very useful?
– Sathyaish
Nov 28, 2013 at 5:19
• Okay, I just got to know you've been doing this since you were young and that you've written a book on mixing audio called Mixing Audio. I also searched some more and found that for someone like me who wants to understand the basics of sound, here is a good book: amazon.com/Sound-Reinforcement-Handbook-Yamaha-Products/dp/…
– Sathyaish
Nov 28, 2013 at 5:37
• The Sound Reinforcement Handbook is a heavyweight one. At this level I'd recommend you just browse 'Basic Sound Theory' online. Nov 28, 2013 at 14:59
• It is the inverse of a cycle period within a signal, not the whole signal. A sawtooth contains a fundamental frequency and odd+even harmonics (frequencies that are an integer multiple of the fundamental). So it does contain more than one frequency. But yes - it is conventional to say "A 100Hz sawtooth", which really means that its fundamental is 100Hz. Dec 1, 2013 at 20:06

## 2 Answers

The sound becomes higher in pitch. Pitch is, basically, just frequency.

"Shriller" is one way to describe this, although it carries a somewhat negative connotation.

• Thank you. Am I then right in assuming the converse, that is -- if I decrease frequency by spreading the data spectrum over a lengthier time-line, the sound becomes basal?
– Sathyaish
Nov 27, 2013 at 21:36
• @Sathyaish That is correct. Changing the rate of data playback is the principle behind most samplers, which play recordings back at different pitches (i.e. across a keyboard).
– Warrior Bob
Nov 27, 2013 at 21:42

I think decreasing sound frequency will spread the sound over longer duration and vice-versa. So if you increase the frequency, on time axis, the sound wave should compress and you can hear the sound at faster speed or at rate of more than 1 (it’s just like what we often do in diff media players... we increase the speed at 1.2 / 1.5 etc. and conversation becomes faster. This is actually done by increasing sound frequency).