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Program Handling and RMS Handling

Discussion in 'Amps and Cabs [BG]' started by deanthemachine, Jul 14, 2005.

  1. deanthemachine


    May 3, 2005
    Can anyone help me out here and say what the difference is? I recently bought a cab, and the PH is 400 watts and the RMS is 200.

  2. Program handling is how much power the cab can handle at very short musical peaks. RMS is the power the cab can continuously handle, and is a more accurate figure for the power handling of your cab.
  3. ESP-LTD


    Sep 9, 2001
    RMS can be calculated and theoretically replicated in a lab.

    Program Power is any number folks want to make up.

    Peak Music Power is often Program Power inflated 2x.
  4. Getting a power amp anywhere between the RMS and Program power is about right. RMS is continuous long term, more for surviving test tones. Hard to drive a 200W amp to 200W avg power with bass guitar. Some notes are louder, some softer, there's rest between notes etc. All those bring the avg amp power going to the speaker down from the amps rated 200W, even if its pumping out 200W relatively often on some notes.

    Most would argue you need more than the RMS rating of the speaker for adequate headroom. Amp at 1.5 to 2x the RMS rating of the speaker is the range I've usually seen.

  5. Headroom really isn't a function of the head-versus-cabinet, it's a function of the system's ability to play as loud as desired.

    You want a quiet note to be at a certain volume, so the amp is turned to deliver enough gain to deliver the desired volume for that note. Then you play a much louder note. The amp is still trying to provide the same amount of gain (assuming the amp doesn't have a comp-limiter). Can the amp do it? If so, there's adequate headroom. If not--and the amp starts clipping (if clipping isn't desired) then there isn't enough headroom.

    Can the speaker cabinet handle the louder note? If the note is clean, and unclipped, maybe, some cabs can handle twice its nominal power rating.

    I think this concept is sometimes misconstrued. Headroom is having more amp capacity than you need. It's really not related at all to the cabinet, as long as the cabinet can take the amount of power being delivered.

    Buying a cabinet rated 50 watts, then putting a 100 watt head on it, doesn't automatically give you headroom. Buying a head capable of producing 1000 watts most likely will give you enough headroom, unless you like music insanely loud. Can the cab handle the 1000 watts? If the amp is set very clean and the musician pays attention, perhaps the 1000 watt head can be set on a cab rated only 500 watts RMS. If the amp isn't set cleanly or the musician is careless, the 500 watt-rated cab may not handle the amp's full power and the speakers may be damaged.
  6. thedoctor


    Jun 20, 2005
    Nashville has got it right. If I may expand a bit, the common thoughts on amp vs cabs is that you always run more cab than you gots amp. That works to the extent of reliablility. An under-powered amp CAN, if fact, do damage to your sound as well as your cabs. Forget "music-power" when buying anything and start with an amp you have or have heard. It is possible to run speakers/cabs that are not up to the potential output of this amp, but you got to use some real judgement in playing. I love two sounds from cabs. A single 15" not pushed too hard and 4 12"s with two 15"s. I can use the same amp for both but I gotta pay attention to how hard I am driving that single 15". The real matching is done by you as you get to know what your equip. will take.
  7. Petebass


    Dec 22, 2002
    QLD Australia
    RMS is an engineering term. Program Power is a marketing term, so ignor it.
  8. I should have said for adequate headroom to drive the speaker to its max safe potential volume cleanly.

    If you play so loud you really can't distinguish distortion, having a lot more power than speakers is going to end badly.

    Harder to blow stuff up with more speaker than amp if you can't tell when to turn down.

  9. That's a good clarification, thanks.
  10. LoveThatBass


    Jun 28, 2004
    If something is ONLY rated in Program or Music Power (one in the same) I will not give it a second thought!

    R.M.S. is what I look for.

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