If you turn your amplifier to the maximum volume it is very probable that you are driving the amplifier into severe clipping distortion. Such distortion can and will damage your speakers and possibly your amplifier as well. Most speakers are damaged by uninformed people doing this exact thing. The crackling sounds your speakers made corresponded to huge amounts of distortion from your severely overdriven amplifier. And most loudspeaker warranties do not cover this type of damage. They see this as product abuse.
If you need higher volume levels then you will need to get a much more powerful amplifier. Remember, distorted power will damage speakers at much lower levels than clean (unclipped) amplifier power...
If you need higher volume levels then you will need to get a much more powerful amplifier. Remember, distorted power will damage speakers at much lower levels than clean (unclipped) amplifier power...