Music Synchronizing Circuit

Thread Starter


Joined 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!



Joined 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.