Video Lab 2

Task

You are required to shoot a number of raw digital video clips on your phones that you will subsequently edit into a short film of duration 5 minutes. The scenario is that your final video could be embedded into a promotional blog that intends to give an impression of the student facilities available at your campus.  The exact style and content of the video is your own editorial choice bearing in mind that since the blog would be promotional, you should attempt to “paint the facilities in a positive light” where possible.

-You may apply incidental backing music (and occasionally tastefully mix this with original audio in the original footage).

-You may edit sound to reduce noise and enhance the overall quality the final video.

-The final film should attempt to emote certain subjective qualities such as “sense of drama”, beauty, space and light, “gritty realism? You have a free reign as to the style of film that you produce

- The film should be exactly 5min long.

-The film should include at least 8 sub-scenes editing together smoothly to create a natural flow to the final movie.

-You may use any of the features/effects/transitions of the video editing and audio editing software that you employ to make your final product attractive.

Link to video 

https://www.youtube.com/watch?v=30E9-vjd9p8&feature=youtu.be

Video Lab 1

Task

A short film is to be used to promote the Gallery of Modern Art in Glasgow (GOMA). A TV company can only show 1 minute of footage. The original footage obtained (in the supplied file) is unfortunately too long and must be edited to be only 60s in length. Using Moviemaker or another video editor of your choice, perform edits to show a smooth walk-through of the gallery.

The reason why I took the part that I did was because that the pan shot of the Gallery is a really good intro and using that piece and using the next clip of walking in and looking at the two marionette puppets was exactly what I wanted. The music I used fits to the 'scene' as, in my opinion, the two puppets are somewhat creepy and the eery music I used conveys to the viewer that there is something just slightly peculiar about them. I tried to get the main part of the soundtrack to  come in when the two puppets were the focus as the film. At the very end of the piece I used a fade out effect to let the viewer know that it was the end of the piece. With a little bit of precise timing I managed to get the music to stop just as the fade out begins. 

The software itself isn't too challenging to use to be honest. It is a good solid simple piece of software that I think anyone can really pick up within minutes of using. The only bad points I could think of aren't really bad points as the software is free and is basic but there are big limitations to what you can do with movie maker compared to other softwares I have used in the past.

If I was to do this again I might want to use a different software and change my approach to the editing. I'd use similar music but I would have used a few more effects that would perhaps slow down the film and blur out the surroundings to focus in on one particular point but other than that I think it'd stay much the same as it is.

Here is the link to the video

http://youtu.be/eRjxbBuKmtQ 

Audio Lab 4

Task 1

Apply a custom filter to the image in the manner discussed in the lecture to filter the image as
Filter > Other > Custom and modify the default mask to :

    -1

-1  4  -1

    -1

The image is switched to a similar fashion as a negative effect that would polarise the colours. The effect is similar to this although it has created the image as a pure black and white image with the highlights and details being left in white and the other colours being changed to black. To be honest I'm not really sure why it changes the way it does although I can guess it will be something to do with the filter changing the pixel values.

Task 2

Experiment with various masks and explore the use of the preset masks in the High pass, Maximum and Minimum options. Where possible describe and explain what you see?

In the first image the intensity of light has been increased however the detail of the image still remains the same. You can still see each individual brick on the clock tower. My guess is that the low frequencies have been altered by the mask effect.

In the second and third images the mask reduces, the second iamge, and increases, the first image. the amount of the colour black in the image. In the second image it is increasing the lighter colours and reducing the number of darker colours. Where as the third image is doing the exact opposite and is increasing the darker shades of light and dulling the lighter colours. I imagine that a range of specific value pixels are targeted and then altered by the masking effect.

Task 3

Suggest possible uses of this filter technique for processing digital photographs?

Possible uses of these effects and masks could be that the High Pass could be used when an image has lots of areas of black you could use the mask to highlight and alter them. Each effect could in their own way be used to smooth out the the pixelation of an image. Perhaps using the High Pass effect could be good to highlight lines in a piece of art. using effects and masks can make an image stand out or from others or even give it an extra edge that was not previously there.

Task 4

Create a new filter that is all zeros except for the center value which should be 1. What does this filter do and why? 
How can you check it operates as you think it does?

The only way to compare that the filter operates as it should it by visually comparing the original image and the altered image. Looking at both images it is clear that nothing has been altered by using the mask. 

Task 5

Create a new filter with a 2x2 matrix with 1's near it's centre. What does this filter do and why?

The mask has brightened the image although some darker colours still remain unaffected. The sky and the lamp glass, being the lightest on the image, have been brightened and almost completely changed to white. Whereas the two stone pillars at the front are still very dark in comparison to the rest of the image.

Task 6

Create a new filter with a 2x2 matrix with +1's on the one diagonal and then -1's on the other. What does this filter do and why?

The image now has been changed in a similar fashion to the first task although it is a more extreme version as the lines and now almost invisible and are hard to see unless you strain to see the smaller details. The values of the pixels have been reversed and altered so that the values are only black and white.

Lecture - More on Light

More on Light

Overview
1. Lightwaves and Frequency
2. The Visible Light Spectrum
3. Effecting Factors on Light

Light Waves

Light is detected by the human eye however unlike sound light does not need to a medium to travel through so this means that once emitted from the sun it can travel through the cold dark vacuum of space to, after 8 minutes and 20 seconds, reach Earth.

Light is a transverse wave, similar to a ripple on the surface of a liquid.

source - the lecture slides

Light is transmitted in electromagnetic waves in a certain form of radio wave and this basically means that our eyes are a sort of receiver. Humans can only see about 400 THz to 750 THz (Tera-Hertz). This range tends to be portrayed using colours starting at red for lower frequencies and then moving to violet for the higher frequencies.

source - the lecture slides

In the vacuum of space light travels at a constant speed of 300,000km/second. Although when travelling through air it is reduced slightly and when travelling through a gas it is slowed by about 1/3. The changing of the velocity caused by the air/glass interference means that using glass is very useful for making lenses. When these waves travel through air they are in fact moving at roughly 1,000,000 times the speed of sound, which is 344m/s.

source - the lecture slides

The frequency of a light wave is related to the medium at which the wave is travelling through. The speed the wave can reach and travel at is equal to the wave length x the frequency. This can be shown mathematically through a simple equation.

source - the lecture slides

The Visible Light Spectrum

A prism with a white light shone through it can be used to show the colours of the rainbow. These colours also show the light spectrum. The cover of Pink Floyd's album can be used to show this perfectly.

source - http://fc07.deviantart.net/fs71/i/2012/067/6/8/dark_side_of_the_moon_wallpaper_pack_by_alphasnail-d4s4nhs.png

As we can see the top of the rainbow starts at red and the bottom is violet. This is the visible light spectrum that is shown with high frequencies and low frequencies. 

Waves with a frequency just under the range of the human eye is known as infrared light. This wavelength is usually longer than 700nm. A laser that is used to operate on CD's works at 780nm. Waves with a frequency just over the range of the human eye is known as ultraviolet light and these have a shorter wavelength of 400nm. Some animals can hear sounds that are outwith the human range and the same goes for their visual capacity. Some animals  have the ability to see ranges that humans cannot such as bees can see in ultraviolet.

source - http://www.wildlifeonline.me.uk/images/graphics/visible_light.png

Affecting Factors on Light

Light can be affected and changed by the environment around it. It can be absorbed, scattered, refracted, transmitted and reflected. Depending on the what the object is made from means that the light can be transmitted differently. A pane of glass that is clean and does not distort light is only visible because of the reflection of its surroundings otherwise it'd be invisible to the human eye.

The intensity of a light source can be mathematically calculated by using the inverse-square law. This is when we square the distance, take this as R, from the source. This can be shown as 1/R².

When light travels through a medium and into another some of the energy is passed on while some is reflected. Light that is reflected from a flat boundary, a calm lake, will form a clear mirror image of the surroundings.

source - http://media-cdn.tripadvisor.com/media/photo-s/01/52/60/9f/emerald-lake-reflection.jpg

Specular Reflection

When the rays of light are hit a plane mirror and the reflected and incident rays are reflected at equal angles we call this reflection Specular.

source - http://s1.hubimg.com/u/4446928_f520.jpg

The angles that are reflected are called the angle of incidence and the angle of reflection.

Diffuse Reflection

Rough and uneven surfaces will reflect in different directions and it is these array of reflections that is called a Diffuse reflection.

source - the lecture slides

Diffuse reflected light is scattered and reflected in many different directions and it doesn't show any highlights or image like the previous Specular reflection. An example would be a light reflection off of a piece white paper.

Lecture - Light

Light

Overview
1. Looking at Light
2. The Play of Light

Looking at Light

Light is constantly being generated, transmitted and reflected by objects in our surroundings which allows the eye to capture images and allows cameras to record footage of the world around us. 

Vidi

This can distinguish between the concept of looking, seeing and observing.

Looking - where we arrange what our eye sees before us
Seeing - this is where we receive energy from light and convert it into nerve impusles
Observing - where the nerve impulses are analysed, interpreted and classified in terms of objects.

The sun will change the appearance of all objects as it each time of day will project a different 'mood' through the changing colours throughout the day. Just before dawn the sky could appear orange or yellow as the sun is beginning to rise. During the morning the skies will be a bright blue colour instead of the orange colour of dawn. As mid-day appears a 'white' light will appear as the sun is at its highest point. Finally twilight has much deeper shades and the shadows cast will be much bigger than previous times of the day.

The Play of Light

The way light affects the world around us can be put down to three concepts that are direction, colour and contrast. The nature of these three concepts can be altered and changed depending on the light that is reflecting off them or being absorbed onto them.

Direction

Direction is the first out of three concepts. There are three types of lighting that can affect an object.

Front Lighting - This occurs when the source of light is located behind the object leaving the object without front facing shadows. An example would be the sun shining on the face of a mountain.

Side Lighting - This will create long shadows which give the object a greater sense of shape, depth and dimension. An example would be a lamp shining to the left of a cup of tea casting a shadow to the right.

Back Lighting - This final concept will give the object the most dramatic composition of shadows. The light source will be behind the object casting the shadow. An example would be someone standing infront of a car headlight as their shadow would be cast infront of them.

Contrast

An image that has a high contrast will be very intense. Each colour will have sharp and precise edges and will be rich and vibrant in tone.
Incidentally low contrast will be opposite. The tones of each colour will blend easier and the edges of each colour will merge together. This creates a easier transition between light and dark areas.

Contrast can be really important as playing with the contrast of an image can bring out hidden details of a picture that wouldn't have been visible if the contrast hadn't been altered.
source - the lecture slides

Colours

Colours have a way of impacting the mood of a picture. So if we see a picture with a lot of a certain colour our brain will process this.

Yellow creates a happy mood and has a upbeat and cheerful visual message.

source - http://www.artnova.si/sola_fotografije_fotografije/langOLite59.jpg

Red is a colour that creates a romantic and warm visual message.

source - http://www.artnova.si/sola_fotografije_fotografije/langOLite58.jpg

Browns and greens are often linked with earth and nature as plants and forests are teeming with these relaxing colours.

source - http://www.artnova.si/sola_fotografije_fotografije/langOLite60.jpg

 Blues will create a calming and tranquil theme as blue is associated with the sea and is a cool colour.

source - http://www.artnova.si/sola_fotografije_fotografije/langOLite57.jpg

Colourise

Colourising an image will change the aspects of each colour in the image. It will change the mood and feeling of the image as a whole. An example of this change is shown below.

source - the lecture slides

Lecture - Digital Image Processing

Digital Image Processing

Overview
1. Why use Digital Image Processing
2. Digital Image Fundamentals
3. What is Digital Image Processing


Why use Digital Image Processing

Digital image processing provides a new flexible environment that can be used to experiment to achieve a desired effect. With digital image processing there is now a much greater variety of image manipulation, transformation and enhancement options that are available. These new options were never as freely accessible with the old darkroom photography developing. Since digital processing has become more widely known this means the number of effects is always increasing.

An image capture system contains a lens and a detector. This detector is often a CCD and is in a linear array or a matrix array of photosensitive electronic elements. 

 

source - http://photocafe.pro/wp-content/uploads/2006/06/ccd.jpg

On an area array sensor there is a grid that is made up of hundreds of thousands of tiny microscopic cells. Each individual cell is less than 5μm in size. Each cell creates pixels by sensing the intensity of the light formed by a lens system. When the resolution of a picture is too low then the picture will appear pixelated and blocky. Most modern devices will have a sensor with more than 1 million cells.

A digital camera stores and captures images in 3 different colours ; red, green and blue. Each cell is assigned a three 8-bit number meaning that each cell has 256 levels. The light is collected by the lens and then it is focused onto the cameras sensor array. While this is happening the light is passed through several filters that remove data that is beyond the resolution of the sensor, compensate for false or incorrect colourations that are caused by colour contrasts and finally reduced the infrared and non visible light levels that disturb the imaging process.

When taking a picture sometimes a pattern of lines or waves will appear on objects or materials in a picture. This occurs when a fiber on an object match the chip inside the camera. However companies incorporated anti-aliasing filters into the cameras so that this would blur the small details but other companies prefer to not use these as it sacrifices the sharpness and crispness of the pictures that the camera take.

Digital Imaging Fundamentals

Pixels 

Digital images are called raster-scan or bitmap images. Each image is made up of a grid of pixels. Each individual pixel is in a path of colour but the display itself is made up of red, green and blue phosphor dots or stripes.

source - http://www.dansdata.com/images/io026/pointer_close.jpg

A pixel is the smallest digital element that is available when using image editing software, Each pixel can be coloured but because the pixels are only an approximation of the colour of the subject then the bit mapped images can sometimes become blocky and have jagged edges. This is the downfall of bit mapped images but they are small in memory size so are some times the better choice. A bit mapped image is represented as an array of groups of bits. Each group codes the colour of the single pixels on the screen. The array could be at 640x480 resolution with each pixel having 24 bits in each group.

640 x 480 x 27 = 7,372,800 bits
7,372,800 / 1024 / 1024 = 7.4Mb

Dynamic Range

The dynamic range is the number of colours or shades of grey. The dynamic range of a digital image, however, is fixed by the bit depth of each pixel. This determines the maximum number of shades of colours of grey that can be accessed in the software's palette.

source - http://bytechunk.net/quake2/quake2_palette.jpg

Bit Depth

A 1 bit pixel will only be able to display 2 values. Black or white. To represent grey pixels in an image a process called half-tone is used. This gives the impression of shading where there is none.

source - http://sweetclipart.com/multisite/sweetclipart/files/halftone_pattern_black_white_1.png

An 8 bit pixel will be able to display up to 256 shades of grey (2^8 = 256) With this number of values it means that representing shading in an image. This shows a more gradual level of shading which is more realistic than only 2 values. 

source - http://upload.wikimedia.org/wikipedia/commons/9/9a/Colour_banding_example01.png

A 24 bit pixel will be able to display > 16 million colours (2^24 = 16million). This is called true colour and each pixel will have varying levels of red, green or blue. This will mean that unlike the previous pictures, where shading was implied or was more blocky and a bit more obvious, a 24 bit picture will be crisp and clear. 

source - http://file.answcdn.com/answ-cld/image/upload/h_320,c_fill,g_face,q_60,f_jpg/v1400839612/s2yb1qiscgsq4gjvucoj.png

Colour Palette

The computer will predetermine the colour palette that is used by the system ie 256 colours will be used for every image. The fidelity of an 8 bit image is enhanced by the selection of the 256 colours that will be used for the image. This is known as adaptive palette but the problem is that it can cause problems when multiple images are being displayed at once on a system that can only display 256 colours at one time. 

source - the lecture slides

source - the lecture slides

Below is an example of an optimised and unoptimised palette.

source - the lecture slides

What is Digital Image Processing?

Digital Image Processing can be separated into 4 main categories. 

Analysis - Operations will provide information about photometric features such as a histogram and the colour count.

Manipulation - This operation is about changing aspects of the picture using tools such as fill and crop.

Enhancement - Functions that will  be for enhancement will be to improve the quality of the image with operations such as edge enhancement and heighten contrast.

Transformation -  As the name suggests the operation is for changing the image with rotation and skew operations.

Analysis

A common operation is the histogram display which plots the various intensity levels such as 8 bit grey scale levels ranging from 0 - 255 on the horizontal axis and then the number of pixels having each level on the vertical axis. 

source - the lecture slides

Transformation

The rotation of image is part of the transformation operation. The pixels are simply remapped.

source - the lecture slides

Manipulation 

The area that is to be changed will be highlighted or selected using a selecting tool such as the lasso and once this area is selected it can then be change and modified. In the case below the selected area is filled in with an orange colour.

source - the lecture slides

Enhancement

An example of enhancement is filtering. This is when the kernel takes the pixel value and multiples it and then totals the value giving the pixel a new output.

source - the lecture slides

Another example of enhancement is blurring which is when the surroundings of an image can be simulated to look blurred to highlight an important part of a picture of a key point.

source - the lecture slides

Audio Lab 3

Task 1
In Audacity open and listen to the file OriginalJingleMix.wav. How many different types of sound can you hear? Can you name the instruments or other sound sources?

The various sounds in the audio track are drums, guitar, bass guitar, voices in unison, a keyboard and a gong. The bass guitar, keyboard and the drums play throughout the piece whereas the voices come in after a few bars of instrumental and then the gong closes the music part of the track. Each of these instruments don't play a particularly hard riff but the use of each one playing together creates the final upbeat piece. 

Task2
Session musicians recorded each of these tracks. Listen to each instrument track individually. Makes notes on the quality of each sound. Quality of sound is very subjective. Use any adjective that you feel is appropriate to describe each sound. Eg, Does the bass sound smooth or punchy? Is the guitar jangly or distorted? How loud does each track sound in relation to one-another?

The bass guitar sounds staccato and has a solid continuous ostinato that plays throughout the audio. The voices in unison sing in harmony with each other creating the sweet sound that is heard. The gong at the end of the piece acts almost as a signal for everything to stop. The piece is played in a simple time of 4 beats per bar. The piano plays a for a bar with a short descending riff.  The drum kit plays a simple rock melody that keeps the rest of the music at a steady tempo throughout the piece. The piece is played to sound major as it sounds upbeat and happy. 

Task 3 
Look at each track in the time domain and frequency domain and make note of any distinct features. Eg, what time does each sound event occur, loudness in dB, duration, envelope shape. What frequencies does it tend to occupy. How do these features inform your own personal impression of the sound as you hear it.

The Rickenbacker Bass guitar starts from the very beginning of the audio clip and hits a height of about -24dB of frequency. The wave changes as the strings on the bass are being plucked or popped as when this happens the waveform becomes erratic. 

The Sweep Bass guitar plays from the beginning similarly to the first bass. The frequency is about the same as the previous bass although the waves aren't erratic but rather form a smooth pattern.

The Timp and Piano are played at the beginning of the music and has a low frequency and a low wave form to match. The sound is about -36dB and it plays for about 5 seconds before fading out.

CEP voices start just after the Timp and Piano end. They fade out after 10-15 seconds in. The wave looks very consistent and has very few breaks or blocky parts to it. The sounds hits a height of about -24dB.

The D Loop and Announcer come into the audio at the same time as the CEP and stop in a few after seconds their part is played. Another part of this is played about 10 seconds after it ends and carries on for the same amount of time as when it was first played. This track has a waveform that is untidy and shows areas of high frequency changing to low frequency in a short time frame leaving the wave to look very inconsistent. 

Dop Organ plays just after the beginning of the audio and stops about 10 seconds afterwards. The repeating pattern in the audio matches the wave that has a repeating pattern that follows when the organ plays and then is muted.

The Drums begin as the intro to the track and have a fairly simple wave until the end when it becomes a solid block of high frequency. Out of all the tracks this audio has the highest amplitude as it is the loudest part to the full track.

Finally the Funk Guitar starts to play just a split second after the track begins and continues throughout most of the track playing in the background. There is a small spike in the frequency near the end but overall the wave is consistent and has a height of -39dB.

Task 4
Use the mix feature of Audacity for each track to create the final mix for this jingle. Be sure to use control-A to select all of each wav before mixing to the waveform mix waveform. Check that the waveform sounds as expected.

The waveform doesn't sound any different from the original jingle track.

Task 5

Using the previously explored features of Audacity, modify the component wav files before before mix to produce a new style of mix. 

1   Make the Bass Guitar less prominent, Make the guitar sound smoother and Make the whole mix sound as if it was recorded in a large room.

Here is the new bass that has been reduced. I lowered the gain to reduce the output the bass track gave.

Here is the new funk guitar which has been leveled to give it a smoother sound to the track.

2      Make a special mix to your own taste, you may edit each individual track before mixing as many time as you feel necessary experimentation is the key here. You can even record you own tracks if you wish or add wavs obtained from freesound.org in the mix.

For my own edited track I took a piano piece and used the cut and paste tool initially to lengthen it from about 30 seconds to 60 seconds. At the beginning I cut and reversed the first piano chords and then equalised it to bring the volume up creating a dramatic beginning to the track. Taking other bits of the track I pasted them and repeated them as they sounded major and pleasant to listen to.  

Task 6

In the early days this was called “Mickey mousing” where an organist in the cinema would improvise sounds to match the events taking place in cartoons and movies. This aimed to create a sense of drama, suspense, excitement and surprise in the mind of the viewer. We can do the same with video computer games or animation. Open the OldMovie file using Microsoft Movie Maker. Watch the film many times and make a note of any events that you consider important.

Using some old carnival music I matched up to the theme of the piece rather than what was happening. An old style movie would obviously deserve an old style theme and as such the old carnival music worked perfectly. 

Audio Lab 2

Task 1 

Run Audacity. Select Tracks-> Add New-> Audio Track which as you can see has defaults setting of MONO, Sampling Rate 44,100 Hz, 32 bit float. Click on the inverted triangle on the audio track to change the setting to 16 bit PCM What do each of these setting mean? 

MONO means that there is only one sound output. So in a standard pair of headphones you will have stereo because there is a right and left speaker but with mono there is only one channel instead of two. 

Sampling rate is when a sound wave is converted into a sequence of samples. A CD will have a sampling rate of 44,100 HZ and a DVD will have a sampling rate of 90,000 HZ.

PCM is when an audio track is taken and then converted into binary. This can be either 16 bit, 24 bit or 32 bit float. Once in binary the audio is represented digitally and is then converted back into the audio. 

Task 2

 Use the Generate->Tone option to generate 1 second of a sinusoid (single pure tone) of frequency 440 Hz at amplitude 1, mono, 16bit, sample rate (frequency) 44100 kHz. Save the pure tone as a *.wav file in C:\TEMP or on your pen drive if you have one. 

Task 3

By using the same option, create similar tracks for each of the harmonics up to and including the 9^th in the proportions shown below. Add the fundamental and each of the harmonics to each other by selecting all waves (CTRL A) and pressing CTRL SHIFT M. Sketch or cut and paste the result into your lab document and describe what you see.

Task 4 

What shape is the waveform gradually approaching? Listen to the wave as you add more harmonics. Does

the timbre change?

The shape of the waveform is slowly becoming squared off and less of a wave shape. The change is at first a fast change to the first harmonic but after then each sequential harmonic changes slightly. The timbre, or tonation, of each wave changes as we progress through the harmonics. The sound of each harmonic is slightly higher than the last.

Task 5

 Similarly to the previous lab view the frequency content (Magnitude Spectrum) of the waveform using the Analyse->Plot Spectrum option. Compare the peaks in this display with the fundamental and the harmonics you have added to it. Sketch or cut and paste the spectrum in your lab note and describe it.

When looking at each harmonic in comparison with the last we can see that a pattern of sorts emerges. The wave is at 0dB and has a slope that goes towards 2000 Hz. When we look at the second peak we see that is starts at a lower -10dB and slopes down to 2500 Hz. This trend of increasing Hertz and decreasing Decibels continues to the last harmonic which peaks at -18dB and slopes down towards 4200 Hz. We can also see that the curve of the first peak and then the curve of the last peak are completely different. This first peak has a much smoother curve whereas the last peak has an almost straight line.

Task 6
Now view the Spectrogram of the waveform using the audio track triangle and selecting spectrum setting. Describe and sketch this result in your note. Save the final waveform as a *.wav file in C:\TEMP. Listen to the waveform and compare it with the sound of the original pure tone sinusoid.

The spectogram shows an intense bright mix of colours. These are to show the varying degrees of harmonics and amplitude of each track. Each track changes in brightness meaning that the brighter ones have a more intense sound whereas the duller tracks.

Task 7

 Now start afresh and add to the Fundamental pure tone the harmonics up to you and including the 5th in the proportions shown below. Display and sketch the waveform each time you add another harmonic.

Task 8

What shape is the waveform gradually approaching?

The wave beings to slowly take on a sawtooth shape as each harmonic is added to the fundamental and as it approaches the fifth harmonic it becomes a full sawtooth wave.

Task 9

View the frequency content (Magnitude Spectrum) of the waveform as previously. Identify the peaks in this display with the fundamental and the harmonics you have added to it. Sketch it in your lab note.

Task 10

Save the final waveform as a *.wav file in C:\TEMP. Listen to the waveform and compare it with the sound of the pure tone, and the previous waveform.

The pure tone sound has a much lower sounding pitch to it. It doesn't sound as harsh and has a lower volume to it whereas the sawtooth tone is a much higher sounding tone. 

Noise, Mixing, Signal-to-noise ratio, and filtering

Task 1

Open the waveform noise1.wav. This is a white noise fule. Listen to this nuisance file. View and sketch this waveform in the time domain and in the frequency domain.

Task 2

Add a sinusoid of amplitude 0.02, 1kHz frequency of 1 sec duration. Does the resulting waveform look sinusoidal? How does it sound? How does it look in the frequency domain?

As the above image shows the wave and tone produced are a sine wave. However when looking at where the frequency peaks it is clear that the white noise is not sinusoidal as it peaks at -36dB whereas all the other sinusoidal waves have peaked at 0dB.

Task 3

View and sketch the spectrum, view the spectrogram, and listen to the waveform. Locate the pure tone if possible. Save the mixed waveform as an *.wav file in C:\TEMP.

Task 4

Try using the Effect Graphic Equaliser options of Audacity to select the tone and reject the noise in the waveform (we need a slider at max at 1000kHz and sliders at zero elsewhere is possible). Does the waveform look more sinusoidal than before? If so is the period of the waveform approaching that of the original pure tone? How does it sound? To what extent did this filtering work?

Looking at both waves side by side it is clear that after using the equaliser the wave is becoming more sinusoidal than before. The white noise is now less visible and prominent than before and overall when looking and listening to both waves it becomes clear than the the filtering has worked. 

Task 5

On waveforms of your choice from freesound.org explore the effect of the other filter options that are available. 

Below is a sound that I downloaded from the website and then added a 'wah' filter to. The first image is the original and the second image is the altered sound. The 'wah' effect works well if the user is listening to headphones as it resonates throughout the left and right ear.