# Beats frequency Definition and 9 Discussions

In acoustics, a beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies.
With tuning instruments that can produce sustained tones, beats can be readily recognized. Tuning two tones to a unison will present a peculiar effect: when the two tones are close in pitch but not identical, the difference in frequency generates the beating. The volume varies like in a tremolo as the sounds alternately interfere constructively and destructively. As the two tones gradually approach unison, the beating slows down and may become so slow as to be imperceptible. As the two tones get further apart, their beat frequency starts to approach the range of human pitch perception, the beating starts to sound like a note, and a combination tone is produced. This combination tone can also be referred to as a missing fundamental, as the beat frequency of any two tones is equivalent to the frequency of their implied fundamental frequency.

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1. ### I Time period of Beat (acoustics)

$$y=2 A \cos 2 \pi\left(\frac{\nu_{1}-\nu_{2}}{2}\right) t \sin 2 \pi\left(\frac{\nu_{1}+\nu_{2}}{2}\right) t$$ Can you explain me the significance of the above equation in the context of waves and oscillations? It's something to do with 'beats,'.
2. ### A problem on tuning fork.

Homework Statement 2 tuning forks A and B, when sounded together produce 4 beats. when B is loaded with wax, the beat frequency remains same. if frequency of A is 212 Hz, then frequency of B is? Homework Equations The Attempt at a Solution since the beat frequency is 4 and frequency of A is...
3. ### A question about wave motion and beat frequency

Homework Statement 3 tuning forks of frequencies 200, 203, 207 Hz are sounded together.find out the beat frequency. Homework Equations Beat frequency= n1-n2 (n=frequency). The Attempt at a Solution I know that beat frequency is the difference in the frequencies of two superposing notes. But...
4. ### Coupled pendulums with different masses

I would like to know how to solve the coupled pendulums problem when the masses of the pendulums are different. BUT the ratio of the masses are known and all other factors are kept constant. Need to find its affect on the beating frequency, but i cannot an equation for this with different...
5. ### Musical Acoustics: Beats

I have a question about 'beats' between two sound waves of slightly different frequencies. Basically, I think I understand everything on this page (and have read a few textbooks on this): http://www.animations.physics.unsw.edu.au/jw/beats.htm . And in practice, I work with this concept all the...
6. ### Device that detect waves in a frequency range and beats

Homework Statement You have a device that can measure sound waves only if the frequency of the wave is in the range ##0.8 kHz- 20 kHz##. You have a whistle that produces sound waves at ##21.5kHz##. You ride a bike moving away from a wall, at the same time you blow the whistle and hold the...
7. ### Beats: frequency of resulting wave vs. beats frequency

The beats frequency heard from the interference of two sound waves with frequencies ##f_1## and ##f_2## is $$\nu=|f_1-f_2|$$ Nevertheless the frequency of the resulting wave is not ##\nu## but the mean value of the two frequencies $$f_{resulting}=\frac{f_1+f_2}{2}$$ As far as I understood...
8. ### Doppler effect and concept of Beat Problem

Homework Statement A cyclist with a bell ringing with a frequency of 658.8 Hz drives towards a wall with a speed of 3.18 ms-1. Just before colliding with the wall the cyclist hears beats, due to the bell itself and the reflection of the sound from the wall. What is the frequency of beats...
9. ### Beat frequency and velocity of observer

Homework Statement Two sound sources 15m apart producing identical 229 Hz sounds. As you move from one to the other, you hear beat frequency of 2.5. How fast are you moving?[/B] Homework Equations The question asks for the velocity of the observer Vo. The trick here is to use the standing wave...