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[Danijel Foler]

hello
Manufacturers of the PA speakers in most cases spec amp to have 2x RMS speaker rating. So, if speaker have 500W amp need to have 1000W. I can confirm that this formula work fantastic and no speaker and amp ever overheating or work with clipping. In this way amp and spekaer work with 50% load. Even for bass you can use 4x RMS rating because peaks. But, 99% active speakers have amps 0.5-1x RMS rating. Why is that??? How large 1kw 18" driver can be driven with 500w-1000w amp? Cant be.

[John Roberts {JR}]

The simple answer is they aren't underpowered.

You need to research the different between driving loudspeakers full range and multi-way. Most powered speakers are mulit-way, and dialed in far better than passive speakers.

It isn't apples to apples.

JR

[Brian Jojade]

The other thing to consider is the potential for damage with higher rated amps vs the minimal increase in output.  By using a smaller amp inside the box, it makes it more idiot resistant.  It's difficult to explain to some people that they blew their speakers, even with the gain controls at less than maximum.

When it comes to powered speakers, just pay attention to the output levels.  The number of watts inside is truly meaningless for anything other than bragging rights.

[Ivan Beaver]

There is no simple answer.  Sometimes it is price sensitive for a particular target market.

Another factor is that many people belive that they can simply turn up the level as high as they want and not tear up the loudspeaker-distortion and compression be damned.

So by using a smaller amp-there is less possibility of damaging the drivers-but it can still happen.

Limiters only work to a certain extent.  They offer a "measure" of protection-but do not guarantee it.

I like to think of it as airbags for your car.  They offer some protection but if you driver you car off a cliff the air bags are not likely to do much for you.

They "assume" normal precautions are taken when driving.  Just like limiters-they "assume" the operator is paying proper attention to what is going on.

Sadly in many cases that is not the case and most people operating sound systems simply do not have a clue. 

[Brad Weber]

Manufacturers of the PA speakers in most cases spec amp to have 2x RMS speaker rating. So, if speaker have 500W amp need to have 1000W.

That may be recommended for many situations but that 500W (continuous) power rating is not what the speaker "needs" nor does having less than 1,000W make it "underpowered".  Whether a speaker has sufficient power is a function of the application, if a speaker gets loud enough for the use with just a fraction of the rated power then it is not "underpowered", while the speaker power rating defines how much power the speaker can handle rather than how much it needs. 

[David Sturzenbecher]

I like to think of it as airbags for your car.  They offer some protection but if you driver you car off a cliff the air bags are not likely to do much

I really like this analogy. Also somewhat related is that if you actually listen to your speakers, you don't need limiters. Unfortunately, most of my customer don't...


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[Bob Leonard]

The speakers are designed and the correct power for the speakers is installed. If the company is honest with their specs and states 130db SPL, then what do you care if it's a 5 watt amp or a 5000 watt amp as long as the cabinet reaches the design goal without self destructing? All too often time and thought is wasted on a non issue, and this is one of them.

[Ivan Beaver]

The speakers are designed and the correct power for the speakers is installed. If the company is honest with their specs and states 130db SPL, then what do you care if it's a 5 watt amp or a 5000 watt amp as long as the cabinet reaches the design goal without self destructing? All too often time and thought is wasted on a non issue, and this is one of them.

The problem is that if a loudspeaker is rated for max of 130dB, then people expect to play music and put an SPL meter in front of it and read 130dB.

This sounds like a good idea-but 130dB is the peak.  If you say that "average" music has a 10dB crest factor (most has more than that) then the typical meter (that has a slow response time (even though it say "fast" will read around 120dB.    So they keep pushing it trying to get to the "rated" 130dB.  Higher dynamic range material would produce lower average readings.

With a meter that can actually respond to the peaks-they would read the rated 130dB peaks.

Things are not always as simple as people would like them to be.

[Bob Leonard]

I agree, so rate the cabinet at 125db. Regardless the point is simple. Who gives a fuck about the amplifier rating as long as the cabinets work as advertised.

ps- Merry Christmas.

[Ivan Beaver]

I agree, so rate the cabinet at 125db. Regardless the point is simple. Who gives a fuck about the amplifier rating as long as the cabinets work as advertised.

ps- Merry Christmas.

But the cabinet can actually produce 130dB-just not in the way most people would like to measure it.

Another example might be saying your car gets 80 mpg.  yet somebody else can only get 30 mpg out of the same model/year.  Well they are measuring it during normal day to day driving, you you got your 80mpg doing down a long mountain.

Your mileage was correct-just not measured how other think it should be.

There are some products out there that state max outputs just like that-with a "special test tone" or such.  Yes the cabinet can produce the max output stated-just not under normal conditions.  The result is that the actual measured and rated peaks are close to 20dB different.

Of course if you rate the cabinets at how the "average person" measures with an "average meter", then there will be others who don't and guess which products people buy?  The one that is rated higher.  Unless they can compare side by side-and THEN the differences quickly rise to the surface.

But most people don't have that opportunity.

The whole problem is that music is dynamic-so there are all sorts of different numbers that could be "presented" with the same test results.  It all depends on what the person stating the numbers is trying to do.

[ProSoundWeb Community]