How to Connect 16 Classroom Speakers to Amplifier with 2 or 4 Outputs: Series or Parallel?

I'm trying to install speakers in each classes (16 classes)  in our school and have each speaker connected to an amplifier. So that the school principal can speak via microphone connected to amplifier and the sound is heard all the 16 classess. 

My challenges are  

1. The amplifier has only four outputs for speakers ( can i wire 16 speakers to those outlet ?)

2. What if the amplifier has only two speaker outlets ( can it accommodate 16 speakers?)

3. i search online for Parallel and Series conection of speakers ( can any work for me ?)

i will appreciate any suggestion 

 

Hi Ene,

You have to check the amplifier specification first, if it can drive these 16 speakers you have at the same time. Wattage rating, etc. , it should matched to the speakers or greater on your amplifier side but you have to be careful since it can damage the speakers.

Hope it helps.

Best,
Neil

Hi,

Further to this - assume that they are 8ohm speakers, then you can connect 4 in series, which equates to 32ohms. Do this for all 16 speakers so you have 4x 4 speakers in series.

Then connect each of these 4x series connected speakers in parallel to one another, which will results on 8oms total impedance.

For public address systems, they use 100volts line- transformers in the speakers with various taps to set the power output. The amplifier, therefore has to be a PA amplifier.

If you can provide the make of the amplifier and speakers, this will help us for further analysis.

Regards,
Richard.

Ene, to expand a bit on Richard's good reply above.  Yes, PA Amplifiers have "100V line" outputs, and you get speakers with transformers with taps for (eg) 0.5 / 1 / 2 / 4  watts.  The speakers are all in parallel across the line.  The total of the wattages selected  must not be more than the Amplifier output capability.
You could get a (say) 20W 100V line transformer and use it back to front on your amplifier to transform its output to a 100V line and then connect your speakers as above.There is an excellent tutorial on 100V line systems herehttp://www.redbackaudio.com.au/understanding-100v-line-distributed-speaker-systems/
As this will tell you, the 100V line system works well on long speaker lines (more voltage, less current and hence less voltage drop) but the transformers do entail some loss of quality - for voice and background music this is not usually a problem though.If you don't want to go this route, as Richard says you can series / parallel speakers to get the right impedance.  2 8ohm speakers in series is 16 ohms, paralle two of those series circuits and you're back to 8 ohms.There's a good illustrated tutorial on this here:https://www.amplifiedparts.com/tech-corner/speaker-impedance-power-handling-and-wiring
Hope this helps, reply if you need more helpCheers / David