Beats

You can also use Audacity to generate tones and then combine them.

 

The GENERATE TONE facility can be used to make tones and the QUICK MIX to combine them.

Often I listen to the 440 ad 441 on SOLO mode swapping between the two and students cannot tell the difference - at least the ones' without perfect pitch cannot.

I believe that there are some materials as part of the 21C science course that use this idea for AM and FM

 

How to show beats on Audacity

• Generate --> Tone (440Hz, I suggest 5s is enough)
• Project --> New Audio Track
• Generate --> Tone (441Hz, I suggest 5s is enough)
• Play each on in turn - they are virtually indistinguishable

• You can zoom in (see image below) to show the difference
• Play them together, the beats jump out and slap you on the face.

 

Combine them to a single trace and see the beats

• Click CONTROL+A to select both tracks 
• PROJECT --> QUICK MIX
• The waveforms combineand the beats are visually obvious

 

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Screenshots

The two tracks - can you spot the difference?

 

 

Well, ok you can if you really zoom in

 

 

The post 'Quick Mix' - Beats are obvious

 

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Thanks to Andy Pugh