Audio Visualizer using Emotion

8/21/2019 Audio Visualizer using Emotion

http://slidepdf.com/reader/full/audio-visualizer-using-emotion 1/7

Audio Equalizer



TABLE OF CONTENTS

The current report will describe and provide an informative breakdown of an audio equalizercreated to adjustable settings per any user preferences using LabVE!" The #nal project for$roject V% &igital 'ignal $rocessing 'ystem &esign% was to apply basic theory and applications of modern digital signal processing% to learn basic theory of real(time digital signal processing% andto develop ability to implement and simulate digital signal processing algorithms using )ATLA*and on real(time &'$ platform" !ithin the project% we must demonstrate that these courseobjectives have been learned+

,nderstand basic concepts of digital signal processing theories and techniques"

&evelop basic understanding of real(time digital signal processing"

&evelop ability to implement digital signal processing algorithms in )atlab and LabVE!"

&evelop ability to implement digital signal processing algorithms on real(time &'$

platform"

Background Information

-



An audio equalizer is a device commonly used in sound recording and reproduction to alter thefrequency response of an audio system using linear #lters"- Equalization is can be broken intothree parts to better understand the process" The three parts are signal acquisition .input/%signal processing% and the output of the modi#ed signal" 0ilters are the main component to theequalization process" These #lters can be used for noise suppression% signal enhancement%

removal or attenuation of a speci#c frequency" The signal processing section of the #lters can be" Audio equalizers are typically constructed in a parallel(circuit manner% where the lowpass%bandpass% and highpass are connected in this con#guration" The #lters are set to speci#edfrequencies based on typical frequencies that can be heard by the average human ear"0requencies a1ected can be analyzed visually by implementing a spectrum analyzer" Thiselement allows the user to see and measure the e1ects as the controls are moved to a particularpreference" 'uch equipment to replicate these speci#c frequencies can be relatively e2pensive"

This can be corrected by using software% such as LabVE!" This can minimize any sizerestrictions and makes it portable for easy transport"

Signal Acquisition

The design of the audio equalizer allows a user to connect audio #les via the 3"4 mm jack" Thiswas chosen to allow compatibility with most audio input devices" The my&A5 is used to acquire

the input signal" The my&A5 is a low(cost data acquisition .&A5/ device that gives students the

ability to measure and analyze live signals" 6ational nstruments my&A5 is compact and

portable so students can e2tend hands(on learning outside of the lab environment using

industry(standard tools and methods"7 8nce the my&A5 is connected to LabVE!% we had to

program the correct to allow the audio to feed into our project9s V" !e had to set the sample

rate and voltage speci#cations to allow the audio #les to play without lag or error" 0or e2ample%

the voltage speci#cations must be set to :7V for the left and right channel for the input and

output" believe this is just a standard parameter for the my&A5 because once the voltage

parameters are e2ceed% an error dialog bo2 will display and stop the V from continuing" n the

diagrams below% we will show how the signal acquisition part of the V looks+

- !ikipedia

7

http+;;sine"ni"com;np;app;main;p;ap;academic;lang;en;pg;-;sn;n-<+academic%n7-+-=<>-;fmid;=3

43;

7



Filters and Signal Processing

Three #lters are created based on common usage in the audio market" These #lters are the

bass% mid% and treble" Each #lter is set to attenuate a speci#c frequency to enhance the signal to

a user preference" The bass #lter is called a lowpass #lter that removes frequencies above the

4-7 hertz" n this particular project% we used a *utterworth ? #lter" ? #lter stands for n#nite

mpulse ?esponse which is used when #lters are needed for @continuous(time processing" The

second #lter is for the mid(tones" A bandpass is created to handle a range of frequencies%

instead of having one cuto1 frequency" The mid(tones are primarily utilized to enhance vocals

and certain intrinsic sounds that are not typically in the lower frequencies" These frequenciesrange between 4-3 and 4BBB hertz" Lastly% the treble is created to enhance the higher

frequencies above 4k hertz" Each #lter is connected to a control element that allows user to

control the amount of output" These control elements are multiplied to have a large multiplied

that is noticeable in the audio #les while being played" After the each #lter is altered% then each

adjustment is added together to form the #nal output that is heard though the left and right

channels" An additional feature that is apparent on the front panel is the left and right balance"

This allows the user to adjust the output to play more to one side" 0or e2ample% if one is seating

closer to the left speaker% he or she can shift the toggle to have more audio to the left verses the

right"

3

'ettings are adjusted to

accommodate audio from

the 3"4mm jack of the left



Filter Congurations in La!IE"

Lo#$ass Filter% Bass &Left'( Band$ass Filter% )id*tone &+ig,t'( - .ig,$ass Filter%

Trele &Belo#'

C

Each #lter is calculated separately and then

summed together to form the #nal output

that is heard through the speakers with the

desired adjustments from the user"



Signal Out$ut and /is$la0

The signal output is displayed in three di1erent methods% 'ound% 'pectral Analysis and

0requency *ands" The my&A5 used again to play the altered audio signal through generating

output signals for the left and right channel speakers" The best way to enjoy music is through

sound" The settings to generate an output signal with the my&A5 are very similar to the inputsettings to acquire the signal" As you can see above in the block diagram% the #nal blue data line

is connected to my&A5 and the spectral measurement element" This allows one to visualize the

data as the sound is being played" The spectral measurement tool performs 00T(based spectral

measurements% such as the averaged magnitude spectrum% power spectrum% and phase

spectrum on a signal" Thirdly% a frequency band was created to visually display the varying

frequencies from the audio #les" n order to develop the bands% we have to covert the input data

into a sine wave" The sine wave is the scaled down into an array which called be later converted

into decibel units" The varying decibels from the audio #les are grouped into 4 di1erent arrays

depending of the frequency level" This is displayed on the front panel as #ve columns consisting

of *oolean indicators" As each frequency range increases or decreases% the indicators match the

variance from green% yellow% and red"

Front Panel /is$la0

"eek*to*"eek Task List

!ee

k

Task.s/

- Dather ideas and complete research about audio equalizers"

*rainstorm to determine best method to implement the

researched data into LabVE!" &evelop outline for report

4



and power point presentation"7 *uild project within LabVE!"3 Troubleshot any problems encountered during the build"

nclude screenshots and begin typing the report for the

project"

C $ractice for the presentation% possibly with notecards" heckthat objectives and goals set have been achieved" )ake

corrections related to format or usage in the report and

presentation"

Conclusion

The audio equalizer is common in di1erent real world applications" LabVE! can be used to

reduce cost provide the same e1ects as you higher end audio equipment" hallenges did occur

throughout the process" )any hours were dedicated to research to understand the elements

required to create a frequency band within the software" Also% we had diFculty developing thecorrect calculations to have the frequency vary as the audio #les were playing" The #lters and

controls for the #lters had to be constantly changed to accommodate the small voltage output of

:7V" 8verall% this was an interesting because it required us to use many engineering design

standards and learn the e2tensive elements within LabVE! to achieve the completion of our

#nal project"

+eferences

I1 "elc,( T,ad( "rig,t( Cameron( )orro#( )ic,ael1 Real-Time Digital Signal

Processing from MATLAB to C with the TMS3206 DSPs1 Boca +aton(FL% C+C

Press12342

=

Audio Visualizer using Emotion

Documents

Transcript of Audio Visualizer using Emotion