Discussion in 'Amps and Cabs [BG]' started by Funkize you, Feb 26, 2005.

  1. Funkize you

    Funkize you Guest

    Nov 4, 2003
    Westminster Ca.
    Ok, so I think after LOTS of searching I got it...

    What it really comes down to is Clipping is pushing the AMP too hard right? It has nothing to do with pushing the cab (But Clipping will Damnage the Cab)

    And "Underpowering" is a "Myth" I read lots of contradictions on both behalf's... so a 1000w 4 ohm Cab with a 500w 4 ohm cab should be "Muddy" with this "Underpowering" effect... But I've also heard that say the Ashdown 300H 307w @ 4 ohms, in a Schroeder 1210 850w @ 4 ohms would sound JUST fine... But if this "underpowering" stuff were true, then it would sound "Muddy" and not "Just fine"...

    So what is it? Underpowering a Myth? Or a Fact?

    Clipping is when you push the AMP too hard?

  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Clipping can and does occur at every stage of the amplification process, from the first stage of the pre-amp to the speaker itself, anywhere in the signal chain where a device is being pushed to deliver output that it is not capable of. There is a simple way to avoid it, and that is by not underpowering at any point in the signal chain. With an amp the easiest way to insure that is to have adequate headroom to handle transient peaks, and that means a big amp, pure and simple.

    Underpowered amps are dangerous to tweeters, not woofers, as a clipped signal contains a higher percentage of harmonics, and this can quickly overload HF elements. If you don't have tweeters to begin with underpowering is seldom problematic. For guitar players both an underpowered amp and speaker is key: it's what gives the compressed distorted sound that they want. The same can apply to bass. You want it clean? Use a big amp. Want it dirty? Use a small one.
  3. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Depends on the rig. In a tube amp, "clip away". The more the merrier. In an SS rig, I'd be very careful. That's why those little lights are there. :)
  4. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    what they said............

    a couple of extras. you can't underpower a cabinet, but you can be underpowered for you application/volume needs. a lot of that depends upon the sesitivity of the speaker cab itself, as a more sensitive cab will require less wattage to be as "loud", but even that depends upon how the cabinet is voiced.

    now, it is true that speakers can sound somewhat different depending upon how many watts are being put into them.
    too many watts will make them sound like they are dying (they are). IME, some speakers sound a bit more articulate with fewer watts, and "thicker" with more watts. Understand, this has more to do with how loud you are playing than the wattage of your amp. with a 100 watt amp or a 1000 watt amp you might be putting 25 watts into your speakers most of the time. all things being equal (which they almost never are) that should sound the same.
  5. Funkize you

    Funkize you Guest

    Nov 4, 2003
    Westminster Ca.
    Well I've talked to some people and am looking into a couple things...

    A Schroeder 1210 + Ashdown Mag 300H (307w@4ohm) head or

    A Schroeder 1210 + QSC RMX850 Bridged (850w@4ohm)with BBE BMAX Pre.

    The Ashdown would save me money, but the Qsc would give me all the power I would ever need...

    But again this is not for a gigging situation, This is just for my room... So a Schroeder 1210 and the Ashdown would probably be more than I need for now, And for all of $600 I could upgrade to a QSC with the BBE BMAX pre pushing around 850w @ 4 ohm.
  6. notanaggie

    notanaggie Guest

    Sep 30, 2003
    It seems to be true that some speakers "come alive" at a certain power level. Not the "near death experience" power level, but considerable power.

    That may be due to some sorts of non-linearity in teh speaker, something about the surround, etc. More common in guitar amps, but can definitely happen with bass rigs too.

    If you DON'T put enough power into a speaker like that, you will wonder why it sounds lifeless. That is the only "underpowering" I am familiar with.
  7. 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
    It is also the inherent nature of human hearing to "come alive" at louder levels, and I would estimate that it is a far more prevalent phenomenon than loudspeakers doing so. In general, though, as IvanMike said, there is really no such thing as "underpowering" a loudspeaker cabinet.
  8. jsbach1982


    Feb 11, 2005
    Denton, TX
    One more thing to consider: a larger (more powerful) amp will almost always have a higher damping factor than a smaller amp. Damping factor is the ability of an amp to 'control' the speaker and keep it from flopping back and forth. I've heard many reports of bass players changing from a small (~200W) head to a larger power amp (~1000W) and observing that, with the small amp, the speakers would almost jump out of the cab on low notes; with the large amp, there was virtually no visible speaker movement at all, even at higher volume levels.

    Lower damping factor would mean the speaker is free to bounce back and forth a little bit after a note ends...or when a new note should begin. This may explain the "muddiness" mentioned in the first post. However, speakers are somewhat "self-damping" and of course different speaker designs will have different self-damping levels. Some speakers may need the extra damping factor from a big amp to stay controlled, while others will behave just fine with a little 200W head. Thus cab A will sound "muddy" when "underpowered", while cab B can hum along fine regardless of input power.

    Oh, and you can get a speaker to 'clip'. Needless to say it is very bad for the speaker and will definitely kill it in short order, not to mention produce funny smells and possibly damage your head/power amp as well.

    Alright, enough from this n00b.

  9. 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
    Not necessarily, although almost all amps lose a great deal of damping ability during the parts of the waveform that are clipped.

    That's probably more a matter of how hard the loudspeaker is being driven, not the power rating of the amp. The overall damping factor of the amp and loudspeaker together will typically be determined more by the loudspeaker and cabling than by the amp. Damping factor is really a very overrated spec.
  10. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Agreed, especially with high Bl product pro-sound drivers that naturally contol the cone's motion quite effectively. Some of the best sounding amps are tube jobs with extremely low damping factors, and some of the worst sounding are solid state with very high damping factors. High damping factors are really only a positive factor with cheaper speakers that have low Bl product drivers.
  11. msquared


    Sep 19, 2004
    Kansas City
    Man, I would use that Ashdown over the BMAX any day of the week. Have you considered getting the Ashdown now and then buying the QSC later on, with the idea of getting another cab and running the line out of the Ashdown into the QSC? Then not only would you have a setup with a lot of headroom, but you'd be able to use the QSC as a PA amp if you were ever in a band situation where you needed it temporarily. Viva modularity!
  12. Joe P

    Joe P

    Jul 15, 2004
    Milwaukee, WI
  13. popinfresh


    Dec 23, 2004
    Melbourne, Aus
    I've damaged both of my cabs tweeters by 'underpowering'. And at times i'l be really pushing the volume and the sound it just bad distortion when i play hard.
  14. Funky Doctor

    Funky Doctor

    Aug 28, 2003
    I don't have any of these problems anymore. I am powering a 4 ohm 1000 watt cab with and 1800 watt amp. Not to mention that the cabinets' sensitivity is outstanding for a bass cabinet. It had a huge sound when "underpowering" it by 200 watts. But the beauty of it all is, which I guess goes back to Bills first post, is that I am using a big amp, that is, I am arely using even half the power it can potentially supply. Headroom city baby! I have such a huge, clean sound that takes to eq very well. And even better, I can carry my amp i none hand, and my cab in the other if I have to, which is often.