Sorry For the Late Reply. :P(i dont have internet connection yet in my house :P) I want to measure a noise in the library. So if the library user causing a noise, the noise level meter will vary accroding to the noise. Basiclly, i want to build an noise indicator. i dont use either the precision half-wave or full wave average or peak detector circuit. --"Without one the LEDs will momentarily blink real-time and be very dim and a blur"?? ??? so do u have any suggestion which one i need to use? "Did you use figure 5 or figure 6 to cascade the LM3915's? Is full-range set at 10V?" So this mean, it is not suitable for a weak signal??? ??? i used figure 6. I'm operating the LM3915 in Bar Mode. Where should i connect the bypass capasitor??? :-\ i used Condenser mic, 2-wire. i' not sure if it has a built-in FET. i'll attach schematic as soon as i caome back online. acctuly i used power amp because i was thought the signal is weak and need to be amplify.