Speaker – Amp – Match

The articles that I have found on power amplifier sizing keep speaking of this “Rule-of-Thumb” and I find differences of opinions on this “Rule-of-Thumb”. By conducting my own study and research, I think I can elaborate on this some to make more since and explain why each of these rules were selected.

I found the three “Rule-of-Thumb” to recommend:

  • 80 to 125% RMS
    • First, there is no RMS in speakers. This value is referred to as continuous for speaker per AES organization.
  • 100 to 150% of RMS
    • If the specification show a difference between the Continuous (RMS) and Peak in only 3dB (2x RMS) then a maximum of 150% of the RMS should be used.
  • 150 to 250% continuous.
    • In case of the specification show 250 Continuous (RMS), 500 Program and 1000 Peak then we are looking at using 200% of the Continuous.

The goal here is to get as much as you can of your speaker with protection of the speaker as a priority. These above rules-of- thumb are worthless.