Music Synchronizing Circuit

Discussion in 'The Projects Forum' started by AndyDomino, May 14, 2019.

  1. AndyDomino

    Thread Starter New Member

    May 14, 2019
    Hi guys,

    I am designing a circuit that synchronizes flashing LED's to music. There are three filters, a low-pass, high-pass, and pass-band filter. I have included an image of one of the three filters. The filters don't seem to be performing exactly how I intended them to. My question is, when designing the filter, should I take into account the input resistance or re of the transistor? Do I take either of those values and add them in parallel to my 60 ohm resistor and design my filter that way? Or do the filtered bands rely strictly on the capacitor and the resistor?

    It's my first time posting, thanks for any and all responses!
  2. danadak

    Distinguished Member

    Mar 10, 2018
    The filter is high pass, is that what you want ?

    The leds connected in parallel with no ballast Rs in series, means
    typically different brightness out of individual LEDs, do you want uniformity ?
    If so connect in series and recalculate the 12V current limiting R.

    Regards, Dana.
  3. shortbus


    Sep 30, 2009
    What you have described was popular during the 1970's and 80's, called a "color organ". Do a Google on it and there should be many schematics, circuits and ideas on how it's done.