Most modern, higher quality amps are well up to the task loading down to 4 Ohms.
And these measurements are often made with swept signals, not music, which is far more complex and very transient in nature when it comes to short term frequencies of complex harmonic content. With music as the signal source, the amp is not stressed at any one frequency at a time as it is during such analyses.
And there are more parameters to examine following your question, and the excellent responses above; that being the size, configuation and materials of your listening room, the speakers and the power output of the amp. Size of room, coupled to speaker type(s), spec. and amp power will largely determine if you can fill that volume at a desired level, regardless of the impedance minimum or phase angle.
Having said that its always good to know what the output power spec of an amp is at impedance minimum it will feed. If the power needed, along with the speakers and room-to-fill-size is met by your amp, then there is no concern.
And these measurements are often made with swept signals, not music, which is far more complex and very transient in nature when it comes to short term frequencies of complex harmonic content. With music as the signal source, the amp is not stressed at any one frequency at a time as it is during such analyses.
And there are more parameters to examine following your question, and the excellent responses above; that being the size, configuation and materials of your listening room, the speakers and the power output of the amp. Size of room, coupled to speaker type(s), spec. and amp power will largely determine if you can fill that volume at a desired level, regardless of the impedance minimum or phase angle.
Having said that its always good to know what the output power spec of an amp is at impedance minimum it will feed. If the power needed, along with the speakers and room-to-fill-size is met by your amp, then there is no concern.