Connect the speaker terminal lead wires, found at the back of the speaker cabinet, to the speaker cable from the amplifier. Test and calculate the right speaker load required for the amplifier output using the following formula; 1/R = 1/R1 + 1/R2 + 1/R3 + etc. ("R" = ohms). If the amplifier output is 4 ohms and 2 speakers are connected in parallel, then the load output is 4 ohms. Compare the output rating of the amplifier to the speaker power for compatibility.
Check the inductance, which is the amount of sound passing through the wire of the speaker cables using the tester. Connect a separate amplifier for the bass guitar, then use a stereo multiple head jack pin to plug in cables from the amplifier to the speakers. Use mono jacks to connect the other guitars to the amplifiers. Switch on the amplifiers.
Place the speakers facing each other to create a central listening position in between the speakers. Turn the speaker on/off knob on, pluck your guitar, then add more volume to test for the sound. Place your palm on the speaker's woofers and feel for vibrations. If the vibrations are present, then the speakers are working.
Run your index finger and thumb along the wires and check if they are correctly positioned. Counter-check the jack connections before testing the speaker; adjust the amplifier settings accordingly by switching it to function mode.
Listen for uniform sound level from all the guitars. The resultant sound has a balanced phase response, output, or input from both amplifiers. Test the impedance (the physical power of the sound coming from the speaker) using your testing kit and the formula a=b/c, where a and b are the effective values, (b is the particle speed) and c is the impedance or the sound power. A studio type of sound, refined and uniform, comes from the speaker.