Passion in Electronics
I was looking to have a wireless stage audio monitor and I was researching how can I be able to do that with less cost. Then suddenly I realize that most of the cellphones today have FM radio built-in so why just take advantage of it? The idea is simple, connect a FM transmitter to the audio mixer and use your phone’s FM radio to listen to the sound from the mixer. tadaaaa! you have an instant simple wireless monitor!
A DI box or Direct Injection box is a very useful piece of equipment used to connect keyboard, guitars and other audio signal source directly to the mixer. DI box function is to convert the unbalanced output of the guitar, keyboards and other musical instrument to balanced output. Connecting an unbalanced output to balanced input of the mixer often led to humming noise which is really unpleasant for ears especially when no one is playing the instrument.
The biggest problem in PA system that most technician hate most is the mic feedback. Feedback is not that hard to eliminate as long as you know what is the cause. There are several common sources of feedback that I will share to you and simple solutions to kill feedback on your system.
Building a “hum-free” audio is not easy till you know what you are doing. It is not as easy as connecting wire into where it should be connected. Especially for grounds, if you connected it into wrong point. Noise usually come from ground loops or connecting a very sensitive signal ground line to a high current ground path. In most cases a star connection is very effective in eliminating the noise.
