Week 6: 02/11/2012

This week in the Lecture we did another test to see how much we have learned and improved since the last one.

We then went to the lab and used Soundbooth to edit the SopranAscendDescend file again.

When the Compression effect, For Voice – Moderate, was applied the waveforms amplitude decreased in size as well as the sound becoming quieter.

The Use of Audio Compressors - What are the uses?

The first, and mostly the only, reason to use compressors should be for the sound. If used properly, a compressor – or more correctly a limiter - will place an absolute cap on the maximum level that can be passed.

This is invaluable for preventing a large PA system from distorting, or making certain that the ADC (Analogue to Digital Converter) does not clip (exceed the maximum conversion voltage).

Digital distortion is extremely unpleasant, and is to be avoided, as with all forms of hard clipping.

There are many other reasons to use compression, for example, many instruments don’t have the sustain that musicians desire. So by using compression, as the signal fades, the compressor increases its gain, so the note lasts longer.

For more examples and more reasons on why it’s used visit: http://sound.westhost.com/compression.htm#why_use

Spectral Frequency Display

This is the spectral frequency display of the file we are editing; it’s consistent with the waveform.

This is the spectral frequency display of the new file, englishwords2, we are editing; it’s consistent with the waveform. Also it is in spikes rather than lines as the words are spoken and not a constant sound like singing.

Reverb

After applying convolution reverb, clean room – aggressive, I found that the file had taken on a more computerizes quality. It sounds more robotic.

After applying convolution reverb, roller disco - aggressive, I found that the file had taken a more echo like quality. It sounds like it was recorded in a large open room.

How reverb is created in a Room

It is created when the sound is bounced off the walls, floor and ceiling and returns back to the recording equipment making the reverb.

 How reverb is created by a computer on a wav file

 The computer takes the track and adds a distorted version of it to the original to create the illusion of reverb.

Computer Speech Transcription

 I tried out this feature on the computer and it managed to pick out a few words with little problem but some of the other words it had difficulty with. It thought some words were in fact two, for example freedom - free and.

The spectrogram, the one above, shows that most of the speech energy is coming from the middle if the word spoke. The begin and end of the word does not have the same amount of speech energy.