How many 8 ohm speakers can I connect to the output of an amplifier that has an 8 ohms output without having sound quality or playback problems?
If the output of your stereo is 8 ohm you can only connect an 8 ohm speaker so that the impedance is maintained. If you connect a 4-ohm speaker, or two 8-in-parallel speakers, the impedance drops to 4 ohm and you overload the sound output circuit and burn it. On the other hand, if the output of your sound is 4 ohm, you can connect an 8 ohm (lower power) speaker, a 4 ohm speaker, or two 8 speakers in parallel, as this will keep the 4 ohm. See, then, that the set of speakers you turn on at the output of your sound should always have a total impedance equal to or greater than the output of the amplifier so that it is not overloaded. See in the site for more information on speaker association.