• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

What causes feedback in a guitar or microphone?

Extracts from this document...

Introduction

Physics Coursework GCSE

What causes feedback in a guitar or microphone?

Just for the record, feedback is actually the mechanism used to control almost every electronic device manufactured. Stability is a critical issue for all of these feedback control systems, and the gain, or level of amplification, used is a critical element in their design. When musicians talk about feedback, however, the connotation is negative because it is the term they use to describe the shreek that results when the gain is too high on the output of an amplified instrument or microphone. There are several potential mechanisms by which feedback can occur when sound is amplified. Let’s deal first with the simple case of a microphone and an amplified speaker. (See the figure, but ignore the guitar for now.)

...read more.

Middle

Unlike microphones, guitars (both acoustic and electric) can vibrate and these vibrations occur at particular frequencies. In fact, the structural vibrations of an acoustic guitar and the acoustic resonances of the guitar enclosure are coupled and serve to "color" the sound of the guitar. These harmonics are what distinguish the sound of a particular guitar. The top surface of more expensive acoustic guitars is

...read more.

Conclusion

A similar mechanism occurs when amplifying the output of an electric guitar. Structural vibrations induced by acoustic feedback can magnify the signal generated by the sensors embedded in the guitar to "pick up" its sound, which leads to instability. Equalization can control feedback by reducing the gain at the frequency at which this problem occurs. One must take care in setting the equalization so as not to eliminate the natural harmonics of the instrument over a desired frequency range, however.

...read more.

This student written piece of work is one of many that can be found in our GCSE Waves section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a star student thought of this essay

3 star(s)

Response to the question

The concept of feedback is explained to some degree by the candidate using a variety of examples. The main problem being the confusing nature of some of the examples that were use and lack of support diagrams.

Read full review

Response to the question

The concept of feedback is explained to some degree by the candidate using a variety of examples. The main problem being the confusing nature of some of the examples that were use and lack of support diagrams.

Level of analysis

The candidate begins by explaining the concept of feedback. It is a good attempt but it gets slightly confusing to follow in places without any previous knowledge of feedback as there are not base concepts mentioned. No diagrams are used which makes it harder to understand. This is repeated throughout the piece.

Quality of writing

The tone of the piece is wrong from the offset as it is in a very nonchalant and discussion tone manner whereas in a scientific piece the tone should be purely factual with no opinion apart from in the conclusion when all facts have been analysed. Punctuation, grammar and spelling all okay.


Did you find this review helpful? Join our team of reviewers and help other students learn

Reviewed by skatealexia 05/08/2012

Read less
Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Waves essays

  1. Peer reviewed

    Mobile Phone case study

    4 star(s)

    Visible light is emitted by sources, such as light bulbs and candle flames. The light travels from the source to our eyes, which act as detectors.

  2. Investigating the speed of travelling waves in water.

    The graph obtained was a straight-line graph. The formula for a straight-line graph is y = mx + c. If this formula is compared to the formula, v2 = g*d, we can see that the speed squared equals 'y', gravity equals 'mx', (the gradient) and the depth equals 'c', (the y-intercept).

  1. The aim of my experiment is to see what factors affect electromagnetism the most ...

    I will follow the method exactly as I have said and plot down some preliminary results. Varying coil wraps experiment- Number of coil wraps Current (Amps) Number of paperclips Mass (grams) of paperclips 0 0.41 0 0 2 0.41 0 0 4 0.41 0 0 6 0.41 0 0 I

  2. An Investigation into the Effect on the Critical Angle by Changing the Colour of ...

    These results show that I should look for the critical between the angle of 35� and 45�. (See also results sheet) This is a graph to show a prediction of the critical angle of coloured light: Results: I chose to use red, green and blue light because they are the primary colours of light Light Colour Result One(�)

  1. Properties of waves

    larger waves have bigger amplitudes and carry more energy iv. Longitudinal waves do not have crests and troughs because they cause particles to move back and forth instead of up and down a. if you make a longitudinal wave in a spring, you will see a moving pattern of areas

  2. IB Physics Practical - Stubbiephone Wind Band

    If we assume that the speed of sound is constant, then the length of the standing wave will be inversely proportional to frequency. That is, if the length of the standing wave is of a large value, frequency will be a low value.

  1. Physics Case Study - Do Sunbeds Cause Skin Cancer?

    Epidermis The epidermis is the top layer, the layer we see when we look at our skin, it contains many different layers of cells within it, as is demonstrated by the diagram below. [1] The diagram can be found on the website, however, all labels were added by me.

  2. Investigating the factors which affect the sideways displacement of a light ray through a ...

    This I will do for 0, 10,20,40,50,60,70 and 80 degrees. I will not do more that 80 degrees because from previous experiments I have found that it is very difficult to obtain results with an angle of incidence higher than 80 degrees.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work