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'Program Handling' and 'RMS handling'... what counts?

Discussion in 'Amps and Cabs [BG]' started by leafthrob, Jul 17, 2005.


  1. hi,

    I'm wanting to add an AMPEG SVT-15E to my current (all Ampeg) set up which consists of an SVT-3PRO amp (which o/ps 450 watts at 4ohms) and an SVT-410HE 4X10 cab (8ohm). I like to play loud and crank the amp close to max volume. I love the sounds I'm getting from my SVT-410HE but want more bottom end.

    However I am a bit confused about 'Program Handling' and 'RMS handling' of the cabs.

    Now the specs of the amp claim that the amp should split 275 Watts to each 8 ohm speaker cab when connected in parallel. The 8ohm 4X10 cab has a 'Program Handling' of 1000W but 'RMS Handling' of 500W. It seems and is safe to use. The SVT-15E has 'Program Handling' of 400W but 'RMS Handling' of 200W.

    Which rating applies with relation to the Output of the amp, the 'Program Handling' or 'RMS Handling'? in relation to the SVT-15E, 200W 'RMS Handling' seems too low for the output of the amp however 400W 'Program Handling' would seem to fit the bill. Basically I want to know if it will be safe to run the amp throuhg the SVT-15E as I don't want to be blowing my new cab. If it is unsafe to use the SVT-15E can anyone recommend an alternative?

    Should I go for a different brand perhaps.

    Does any one know of any 8ohm 18" subs or larger?
     
  2. jeffhigh

    jeffhigh

    May 16, 2005
    RMS is what counts, but check your specs, if you have an amp rated at 450 watts RMS at 4 ohms then you should be putting 225watts RMS into each 8 ohm box in parallel (which gives a 4 ohm load) What your specs may be saying is that the amp will put out 275 watts into 8 ohms. Your combined speaker load of 2 X 8 ohms cabiinets in parallel will give 4 ohms.
    And 225 is a lot closer to the 200w rating of the cabinet you are proposing than 275
    Jeff
     
  3. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    "Program" power generally means that it's the highest reasonable amp power recommended for the loudspeaker for most users. It's usually about double the speaker's continuous average (a.k.a. "RMS") power rating. The idea behind "program" power is that if you're using the amp and speaker for normal audio, music, voice, etc., as long as you don't drive the amp into significant clipping, the actual average power into the loudspeaker is low enough that it is very unlikely to be damaged.

    So match up your amp to the loudspeaker's program power rating, and it'll be a good match.
     
  4. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Pretty much what Bob said.

    Depending on what sort of music you play, you can go OVER the program rating just fine. For jazz, usually go for it. For industrial thrash punk, get closer to matching the amp and RMS.

    The other issue is that electrical power isn't the whole answer.

    Speakers have a power limit that varies with frequency. If you go over it, you may make the speaker suspension move too far, and mechanically damage the speaker, even though the voice coil isn't burnt.

    You said you want more low end, which is normally where that shows up. So you would probably want to be closer to the RMS than if you tuned the sound towards a more mid-bass sound that projects well.

    That said, no speaker you mentioned is in any serious danger in your setup.

    BTW, if you want tons of low end, 450W probably won't get there. Lows suck up power like mad. If you want them being shook up all over the room, you need a much bigger amp, like 4 times more powerful, or more, with speakers to match.

    You might try NOT getting too lows-heavy, using the second harmonics to get the low end effect without having to use all your power on lows. Just a thought....depends on your goals.