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Project Presentation Discrete Time Signal Processing. The Designing Of Audio Equalizers Using Low Pass, High Pass & Band-pass Filters by Muhammad Akbar Ali Khan & Muhammad Ashfaq. sound.
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Project PresentationDiscrete Time Signal Processing The Designing Of Audio Equalizers Using Low Pass, High Pass & Band-pass Filters by Muhammad Akbar Ali Khan & Muhammad Ashfaq
sound Low Pass Filter Band Pass Filter High Pass Filter Woofer Mid Range Speaker Tweeter Abstract • Description • 3-band • Simplest multiband equalizer
Why we chose this topic • WE have a “little!” study of the low-pass ,high-pass and band-pass filters in various DSP courses , so instead of selecting some robot-science-oriented project, we tried to do something related…
Introduction • Background study • Equalization :is the process of changing the frequency envelope of a sound in audio processing. In passing through any channel, an audio signal will "spread" from its original qualities. The goal of equalization is to correct, or make equal, the frequency response of a signal. • Some kinds of EQ • A peaking equalizer • A parametric equalizer • Shelving-type equalizers • Graphic equalizers
Introduction(cont’d) • Applications • Equalization is used to compensate for the discrepancies of a room’s acoustics • Early telephone systems used equalization to correct for the reduced level of high frequencies in long cables. • live event, where microphones and speakers operate simultaneously. • Equalization was also applied to correct the response of the transducers
Methodology • Explaining your approach / algorithm • Designing Equalizer in Maltlab • Use of filters. • Designing Equalizer in VDSP++ • Using FDA tool, designing filters. • Importing filters to VDSP++.
Low pass filter Convolution process Write To file Band pass filter Sound file High pass filter Block diagram of the whole project
Explanation of The Approach we Used: • [x,fs]=wavread('sound.wav'); • Wn=0.30; • N=150; • gLP=1; • gBP=1.5; • gHP=1.5; • LP=fir1(N,Wn); • Wn1=[.30,.70]; • BP=fir1(N,Wn1); • Wn2=0.70; • HP=fir1(N,Wn2,'high'); • figure(1) • freqz(LP); • figure(2) • freqz(BP); • figure(3) • freqz(HP); • y1=conv(LP,x); • y2=conv(LP,x); • y3=conv(LP,x); • yA=gHP*y3; • wavwrite(yA,fs,'Equlizer3'); • yB=gHP*y1; • wavwrite(yB,fs,'Equlizer1'); • yC=gHP*y2; • wavwrite(yA,fs,'Equlizer2'); • yD=yA+yB+yC; • wavwrite(yD,fs,'Equlizer4');
Results And Discussion (cont’d) • Matlab Code Simulation
Results And Discussion (cont’d) • VDSP++ Simulation
Sound effects for an equalizer • Input Sound file • Low Pass Output • Band Pass Output • High Pass Filter • Total Output
References • Websites • www.google.com • www.wikipedia.com • Books • “Discrete Time Signal Processing” By Alan V Oppenheim. • “DSP First” By James H. McClellan, Ronald W. Schafer & Mark A. Yoder.