500w. 250w rms

[LordAJ]

Hello

 

If I have some speakers with a peak of 500w and 250w rms.

 

If I run the speakers at over 250w continuously what will happen. Is there a reason they are 250w rms?

 

Thanks

[Rob_Beech]

You should get noise out of them.

 

The peak rating is a short term rating, the speakers will be able to handle 500watts for a short period of time, of course, we don't know what this short period of time is, it may be 1 second, it may be 1ms.

If you have a clean signal at 250watts rms, then everything should run nicely. However, we usually expect a little headroom above what the speakers can handle as the speakers handle more for short term.

 

 

Rob

[LordAJ]

ok Thank you

[Simon Lewis]

To be more specific, the manufacturer's rating (250W in your example) is the continuous average power that the loudspeaker can handle before either thermal damage (voice coil varnish burning, voice coil copper windings melting, glue holding voice coil former to cone breaks down etc.) or physical damage (over excursion etc.) takes place.

 

The key thing is, the peak to mean ratio of music is much less than that of a sine wave, and as long as the physical excursion limits are not exceeded, the loudspeaker can reproduce peak levels much higher than its continuous rating - hence the 500W peak rating in your example.

 

The manufacturer doesn't know what you will be playing through the loudspeaker, so he has to give a power handling figure somewhere between its thermally limited capacity (just in case you do listen to pure sine waves at full tilt!) and typical music which has less "energy under the curve".

 

Simon

[Sound In Gloucestershire]

whilst it "should" be capable of doing 250w continuous, some cheaper brands are so easy to blow if you put the quoted wattage into them

 

what are the make and model of speaker?

[johndenim]

In waiting for the OP for an answer, I would like to mention that 'peak rating' IMO is a retailers way of selling you crap.

Why advertise the fact that 'x' cab can run fine with 'x' watts rms but it will peak at 'x' x200?

Who gives a damn?

Like Rob states it may only be for a ms, what good is that?

Wrms is not my choice method of learning performance, (ie, dB's or spl) so why do we get this crap in 'watts' everytime?

An F12 (martin NOT yamaha) may have a lower 'wattage' that a dB tech 12" box, (for example) but that does not mean it will be lower in volume or quality.

[paulears]

You've misunderstood John. There are two things here, and they are very different. We've got electrical specifications - these deal with data that can be used in calculations, so Watts, impedance etc are things you can consider when planning an efficient system. You're quite correct that volume is different - that's why we use a dB scale to give meaningful data there. So to get a total 'picture' you need to know about the electrical energy going in, and the sound pressure coming out - nothing strange at all?

 

Trouble is, we have no quality measurement system apart from our ears. RMS measurement doesn't really reflect music programme - classical would be rather different from drum and bass, so the peak levels claimed are just an indication, and most people treat them with suspicion. I suppose it's a bit like cars having tachometers and speedometers. They both interact, and give useful info, but having an engine that red lines at X000rpm doesn't really say that much to the average driver - but the speedo is far far more use, but doesn't tell you much about hard the engine's working.

[Simon Lewis]

I would like to mention that 'peak rating' IMO is a retailers way of selling you crap.

Why advertise the fact that 'x' cab can run fine with 'x' watts rms but it will peak at 'x' x200?

Who gives a damn?

 

John,

It's true that cheap and cheerful speakers might have spurious 'peak power', 'music power', or even 'peak music power' ratings to deceive and beguile. However, we do want to know that a loudspeaker can handle short term transients, as this may give a good indication of how it will handle real world music signals.

 

However, the average power that the loudspeaker can handle is an important figure to know, because it helps us to know what the thermal limits for that device are. You are right that its power handling figure does not necessarily indicate its acoustic output, but we need to know the sensitivity and power handling data.

 

Incidently, dBs are just a power ratio... that can show the relationship between two measurements of acoustic power or intensity or electrical power. By a small change in the maths, it can also show the relationship between two measurements of sound pressure or voltage.

 

Simon