Matt Ion wrote:
> Richard Crowley wrote:
>> "isw" wrote ...
>>> Radium wrote:
>>>> Auditory-clipping can damage speakers. Can visual-"clipping" damage
>>> No. Prolonged blacks can damage television transmitters, however (video
>>> is inverted for transmission, so black requires full power from the
>> Prolonged bright areas (whether clipped or not) will damage CRT
>> monitors. I have two on the bench right now to have their CRTs
>> replaced because the image is burned-in. They came from a
>> security/survelience application and you can somewhat see the
>> hallway and the doors they were monitoring.
> ANY static image for a prolonged time will cause burn-in on a CRT or
> plasma display. The brighter it is, the less time it takes, but it
> doesn't have to be pure white for burn to occur. Simply displaying 100%
> white won't cause instant death of a monitor, however, the way a clipped
> signal can damage a speaker.
Speaker damage occurs when the *speaker* clips. It's a result of the
voice coil hammering against the stops. Woofers and midranges are
protected from the high frequencies that clipping in the amplifier
generates by their crossover networks. If a tweeter isn't underrared as
tweeters often are, they won't be damaged by the acceleration forces.
When an amplifier clips, there's no longer feedback to lower its output
impedance, and the high output impedance also protects the speaker from
There are few speakers that can withstand the full output of a 500 W
amplifier even when the amplifier doesn't clip. Speaker ratings apply to
short bursts of power, not continuous abuse. A 10%-efficient speaker
driven at 500 watts is having 450 W of heat pumped into it. A two-slice
toaster runs about 800 W. How long before the voice coil smokes?
Transmitter and amplifier tubes have two ratings: CCS and ICAS*. There
is significant difference. Speakers are rated what I call MDFR**. What
will the salespeople tell you, that the rating is bogus or that clipping
burned it out?
* "Continuous commercial service" and "intermittent commercial and
** "Market-driven fictitious rating"
Engineering is the art of making what you want from things you can get.