# Combining multiple Speakers Impedance - what is the preffered way?

I'm building a custom sound system using the HiFi Berry Amp2 which claims to [...] "work with all speakers or 4-8 Ohm impedance. It supports sample rates from 44.1-192kHz (16-32bit)." According to this graphic I conclude to have two channels (i.e. right and left) which each works well with an impedance of 4-8 Ohms.

So far I have four speakers, all with 4 Ohms impedance. Now I calculated for resistors in series a total resistance for each channel of my amplifier:

``````R_total = R_1 + R_2 = 4 Ohms + 4 Ohms = 8 Ohms
``````

I connected the speakers and everything works well.

Now some people told me not to connect the speakers in series and a parallel connection would be preferably. Due to a more flexible design (being able to plug in and out additional speakers) I also would prefer a parallel connection using for example four speakers with 8 ohm. Since for resistors in parallel connection I calculate for each channel with two speakers:

``````1/R_total = 1/R_1 + 1/R_2 = 1/(8 Ohms) + 1/(8 Ohms) = 2/(8 Ohms)
=> R_total = 4 Ohms
``````

Which also fits into the specification of the amplifier.

Now my questions:

1. Is the a preferred way of connecting multiple speakers to the amp? If so, how? Or: Is there any problem with connecting speakers in series like described in my current setup?
2. Would it be possible to have a mixture of 4 Ohms and 8 Ohms speakers, by maybe adding additional resistors into the circuit?** If yes, how?

** = Since I have one 4 Ohms speaker which kinda is in-build and cannot be swapped, but I also would like to give the parallel connection setup a try.