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What's the difference between RMS and Program?

Discussion in 'Amps and Cabs [BG]' started by skit_skittson, Apr 23, 2002.


  1. I was looking at the Ampeg svt4x10 and it said it could handle 400W RMS or 800W Program. What does this mean?
     
  2. Chuck M

    Chuck M Supporting Member

    May 2, 2000
    San Antonio, Texas
    There are many ways to rate the output of a power amp. Some of the ways make the amp look better than it really is.

    The rating that is generally accepted as most meaningful is continuous watts RMS with the ohm load, % distortion and frequency range stated.

    Speakers are also rated in Program or RMS watts and, again, the continuous RMS rating is the one to look for. The Ampeg speaker system should be able to handle the output of a 400 watt RMS power amp.

    "Program" or "peak" watts is not very meaningful in the world of bass amplification.

    Chuck
     
  3. rcrimm

    rcrimm Commercial User

    Jun 20, 2000
    Meridian, MS USA
    Customer Service, Peavey Electronics
    Continuous is the amount of power a speaker can handle if it were a single sine wave, ie; a tone test signal.

    Program is your practical power rating. Program represents your average music and/or speech signals. The “average” user should match amplifier power to speaker Program power rating.

    Peak is the power rating of occasional, short-duration signals like the initial hit on a cymbal crash.

    Program is usually twice the continuous (RMS), and peak is twice the program (or 4x the continuous).

    Note: An RMS amp rating directly correlates to a speaker's "continuous power " rating.


    Here is a little more "scientific" version:

    CONTINUOUS POWER
    This power rating represents the most conservative statement of the capability of an amplifier. It is also called "RMS" power. It denotes the amount of power an amplifier can deliver when amplifying a constant steady tone. It is usually measured at a signal frequency of 1000 Hz for a specific distortion. The continuous power in watts: W = V2/R Power in watts equals the voltage squared divided by the resistance of the load.

    PROGRAM MATERIAL
    A signal, such as speech or music, that contains voltages continuously changing in both frequency and voltage (time and amplitude)

    PEAK POWER
    Peak power is used by some manufacturers in an attempt to "look better" in print and has no bearing on the actual performance of an amplifier. Usually, a power amp's peak power rating works out to be twice the program power and four times the RMS rating.
    Some of these same manufacturers have come up with yet another power term referred to as "Instantaneous Peak Power," which is a further inflated and equally meaningless specification.