How to match a power amplifier and a loudspeaker array?
Power output capacity: 75 VA into a 3 ohm resistive load


So your power amplifier can deliver the highest power into a 3 ohms load.

If you would connect all speakers in series you would get 30 x 8 ohms = 240 ohms, then the maximum power to the speakers is limited by the voltage that the amplifier can make. This is about 15 V, into 240 ohms that means P = U^2 / R = 15^2 / 240 = 0.94 Watt which is not much.

If you would connect all speakers in parallel you would get 8 ohms / 30  = 0.27 ohms, then the maximum power to the speakers is limited by the current that the amplifier can deliver. This is about 5 A, into 0.27 ohms that means P = I^2 * R = 5^2 * 0.27 = 6.8 Watt which is more than the 0.94 Watt but still not much. Also, this quite low impedance of 0.27 ohms is bound to cause problems, the amplifier simply might not like it.

Your best bet is to combine series and parallel to get close to 3 ohms. My guess is that 4 Ohms would be good enough as well and somewhat easier as two 8 ohm speakers in parallel equals 4 ohms. Then use series and parallel again to add more speakers but keep a total of 4 ohms, like so:







simulate this circuit &ndash; Schematic created using CircuitLab

There are 8 speakers, between the top and bottom there's 4 ohms.

You can combine 4 of these in series and parallel and then you'd need 32 speakers.

If you must have 30 speakers maybe you can use 5 x 6 = 30 meaning make sets of 5 speakers in series, connect 6 of those sets in parallel, that would result in a total of 8 ohm * 5 / 6 = 6.7 ohms.