Check also the impedance of your microphone and the input impedance of your mic input to the amplifier you are using. If your mic impedance is higher than the input impedance of your mic input then you will have loss of signal strength.
Generally dynamic mics with low impedance are better than mics with high impedance. Mics with high impedance are generally cheap but they do not work well with long cables - poor audio and loss of high frequencies.
Mics for professional use generally have impedances below 600 ohms (low impedance mics) but they are quite expensive - a few thousand pesos each.
Medium impedance mics (600 ohms to 10K) are relatively cheaper (<1000 pesos) and are usually OK for household use and common PA use.
High impedance mics - usually cost below 300 pesos each. I suggest you forget them
Piezo and electret mics have high impedances but they usually come with a buffer circuit that has low output impedance so they are generally OK. Professioanl versions of piezo/electret mics are quite expensive too.