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Head Room?

Discussion in 'Amps and Cabs [BG]' started by Thunder_Fingers, Jul 31, 2004.

  1. Thunder_Fingers


    Jun 24, 2004
    somebody please explain the thing "head room" to me? and the whole "wich should take most wattage" thing?
  2. Headroom is the available power resourses of an amp. Underpowered amps will distort badly when given more than they can handle and the resulting distortion is bad for your speakers and for the amp itself. It also sounds bad.
    I'll let someone else answer your question on "wichj" :meh:
  3. De Teng

    De Teng

    Oct 27, 2003
    Utrecht, Holland
    Let me be so free then...

    As far I am informed/as far I have been given some insight in the past time, it's a strange issue. In fact it's about two theories.

    I The amp should have a lot more power. Nobody sets the master of his amp to ten, because of the distortion thing, giving bad tone...etc.. The speakers now, which give a better response when they are connected to a powerful head, because the amplitude of the conus is then larger... some say it lets the speaker live and therefore gives a lot more dynmical sound. (or anything..blabla)

    II Then we have the speakers. Because the amplifier (in fact you with your playing style) can give large peaks in terms of power, which can become too or even three times (If you are really unlucky) the RMS power. This abbreviation means Root Means Square, in fact the 'normal maximum output.' (It's a graphic thing, which is commonly used) The peaks for let's say a 300W head (RMS) can be 700W then, so be aware for your speakers, if they can only be able to handle 350W peaks. Boom... catching! €€€€ lost. (or dollars)

    The best solution? Check for yourself. If you don't slap and always use the compression, you could go for option 1. If you do slap and play with a lot of dynamics, go for option 2.
  4. basss

    basss Supporting Member

    Aug 27, 2001
    I has to do with whether you wear boxers or briefs.
  5. I'm short, so I usually have plenty of headroom. :D

    But seriously, your speakers generally have no option but to reproduce what's coming out of your amp. If you drive your amp into clipping, your sound will be distorted. At this point, you are better off getting a more powerful amp rather than new speakers. A lot of people would tend to think it was the speakers that sound bad. So, for example, you might want a 400W amp to drive a 300W cab, giving you 100W of headroom. It would allow you to push your cab to it's maximum without distortion. Keep an eye on the clip/limit leds on the amp, and back it off until you only see the occasional blip when you hit those transients as mentioned above. At the other end of the scale, a 1000W amp into a 300W cab would be bad if run at full power due to the additional power causing the speaker cone to extend further than recommended for sustained periods.

    OK, some math to back up what I'm saying. This is where I get a bit hazy due to it being ~20 years since I've even thought about this stuff. Hopefully someone will chime in and (nicely) correct me or confirm this, as I could probably do with a refresher myself. :)

    RMS is a kind of 'average' of the peak signal, and I vaguely remember it's .707 of peak. Using my 400W amp and 300W (RMS) cab example above, the cab should handle ~425W peak (300 / .707 = 424). Your amp will start clipping before then, but you already backed it off as suggested, right? At this point you should be playing loud, proud, and distortion free. ;)