music equalizer......................

Discussion in 'Homework Help' started by ananya.M, Feb 3, 2008.

  1. ananya.M

    Thread Starter Member

    Feb 3, 2008
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    :rolleyes:do anyone have got a idea of how to build a music equalizer circuit... tat is as u see in many players like winamp,windows media...the output should vary with ur input(tat is any song).... interesting...but how?
     
  2. thingmaker3

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    May 16, 2005
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    Can you provide definitions for "tat" and "UR i/p?" I was unable to find them in my electronics dictionary.
     
  3. JoeJester

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    Apr 26, 2005
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  4. Dave

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    Nov 17, 2003
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    Would I be correct in thinking that the graphics equalisers in Winamp and Window Media are implemented in software and not hardware? If so, are you looking for a hardware circuit or a software program?

    Dave
     
  5. ananya.M

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    Feb 3, 2008
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    sorry...I will be more specific....all I need is a hardware cicuit... a circuit that takes music as input(stereo output from a laptop) and gives an output which depicts it in any electronic form... thanks for the replies and i do think you will suggest something on this....
     
  6. JoeJester

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    Do you want to replicate the "display" like in winamp or windows media player?

    If that is so, you need to decide on how many displays you wish to have.

    Look at the LM3914 to drive the display .... one for each band in your graphic equalizer.

    Look for schematics of bandpass op amps.
     
  7. beenthere

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    An LM3915 voltage level bar/dot indicator would also fit the requirement.
     
  8. thingmaker3

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    An analog VU meter would also fit the description.
     
  9. JoeJester

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    I think the OP wants to replicate the attached display ...
     
  10. thingmaker3

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    The VU meter is out, then. Looks like what is needed are plenty of 3915's and a pound or two of green LEDs.

    Or a microprocessor driving an LCD display.
     
  11. JoeJester

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    Don't forget plenty of filters to discriminate the bands. :D
     
  12. ananya.M

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    Feb 3, 2008
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    thanks for the ideas... but I am not clear about some points...
    Here I am going to divide the input signal(that is music,from 20hz to 20khz,the possible range) in to number of bands(by using filters ofcourse:D) I need.. suppose that I use four bands ... should I use one LM3915 for each band(output from four filters)... I understand that LM3915 senses VOLTAGE levels and drives 10 LEDs accordingly.... but I want to make the LEDs glow for four different FREQUENCY bands only...Isnt it?I am a lot confused here... will someone explain me this in simple term please...
     
  13. beenthere

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  14. ananya.M

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    Feb 3, 2008
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    any ideas of what displays can be used after I filter the audio input in to a number of bands... should I use one LM3915 for each band?:confused:
     
  15. JoeJester

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    yes.... for your four band graphic equalizer, that's four filters, four LM3915s, and forty LEDs. Work on one circuit and then replicate that same circuit four times.
     
  16. nomurphy

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    Aug 8, 2005
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    JoeJester's graph shows a 48 channel display, which may be a bit too ambitious to attempt.

    To simplify the design, yet cover the concept, I would suggest a 3-band with the following audio divisions:

    Low-pass = < 500 HZ
    Band-pass = 500 <> 3KHz
    High-pass = > 3KHz

    I would use either a 3-pole Butterworth design, or a 2-pole Sallen-Key. And an easy way to make a bandpass, is to run a 500 Hz high-pass filter into a low-pass 3KHz filter (or vice-versa).

    Also, you could use three 10-LED bar graphs set vertically side-by-side (see attached). Each bar graph would then display the relative amplitude of the audio signal within the given band.

    Note: Avago was formerly Agilent, which was formerly HP.
     
  17. JoeJester

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    48 channels may be a little ambitious, but that's what the OP wanted ... the winamp or media player graphic analyzer. Double that if they wanted a stereo display. 48 channels for the left and 48 channels for the right.

    I'm sure they would have had fun doing the project.

    I agree with you and beenthere though. A three or four band project would have been easier to manage while getting your feet wet.
     
  18. ananya.M

    Thread Starter Member

    Feb 3, 2008
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    Hi dudes ...Thanks for the reply..I have decided to do a five band equalizer..I have made the audio divisions as
    Low pass:<4Khz
    band pass:4-8khz
    8-12khz
    12-16khz
    high pass:>16khz
    is the way I have divided right or should I do it in some other way....SUGGEST ME PLEASE....and I will also use the LM3915 that you have suggested.
     
  19. JoeJester

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    You do realize that voice is typically defined as 300 - 3 kHz. AM radio typically is 7.5 kHz sidebands.

    I guess your divisions will be whatever you feel is best for your visual representation.

    Visit http://sound.westhost.com/project78.htm and look over the frequencies used in the crossover circuits. You can take the low pass frequency and the high pass frequency for two of your graphic equalizers. Then split the mid-range frequencies by three for the remaining equalizers. But like I said, the choice is yours.
     
  20. Papabravo

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    Feb 24, 2006
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    If you do a real time FFT you can extract the frequency spectrum from the music source and create the display in a number of different ways. If you want to build an actual equalizer then you need to construct a bank of bandpass filters with variable attenuation so you can adjust the response of the output.
     
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