Amplifier Power Ratings - RMS vs MAX, PEAK, & IPP

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Amplifier Power Ratings - RMS vs MAX, PEAK, & IPP


These are just a few of the names used to advertise an amplifier or speaker systems capability. They vary between brands and are generally just a confusion causing mess. Manufacturers use a wide range of names and numbers to imply how 'loud' their equipment is, as this seems to be the figure that has the largest effect on sales, especially in the PA speaker market.Sadly, most of these figures are pure meaningless sales jargon and have no real-world bearing on the audio performance you should expect from the equipment.Retailers are forced to use these figures in order to keep up with competitors, and because many of the manufacturers demand it. This sadly leads to websites being littered with wildly inflated power ratings on equipment, which makes the selection of suitable products extremely difficult for the general consumer.

Where possible, we try to display the RMS rating clearly on all of our audio products, and usually the Max and sometimes the Peak power too for simple comparison, seen here in an example on ourSkytec SPL-1000MP3 2 Channel Power Amplifier


Audio power is the electrical signal that's transferred from an amplifier to a loudspeaker and is given as a measurement of electrical consumption (watts). It is this electrical power, together with the speakers' input sensitivity and its driver properties, which determines the sound output level that's generated.The design of an amplifier circuit and its components limits the electrical energy it can produce, as do the electro-mechanical properties of the speaker system used to convert that energy into movement.

In real simple terms, an audio amplifier takes a small AC electrical signal from any audio device (CD Player, MP3, instrument) and makes it a lot bigger, giving it enough juice to operate the mechanical push and pull of the attached speakers. The design and quality of the amplifier and the speaker components will either aid or fight this from happening.

Other factors also affect this energy conversion process, with the largest roadblock being heat production, which increases resistance and current draw, lowering the rated performance of the system significantly.



RMS is an average measurement of the power transfer between a generator (amplifier) and the attached load (speaker). It is a reading taken from the signals AC sine wave with a set test signal frequency and voltage to the input.RMS, orRoot Mean Square.(Mean Power) The only accurate, consistent and comparable measurement of power exchange that should be used for both amplifiers and speakers.

There is only one comparative power figure that is truly useful, and that is RMS!

Manufacturers of lower-priced components and audio equipment often promote power figures of as much as 10 times the RMS specification, purely for marketing purposes. In real basic terms, the higher the RMS figures in amplifiers and speakers, the louder and cleaner your music will sound. When choosing an amplifier or active speaker system, the RMS rating is the power rating you should pay most attention to.

Program Power (PGM)

Program power is also taken from a measurement of the AC sine wave. However, unlike RMS, Program is the maximum wattage capability in bursts. It is double the RMS measurement.So for example, a speaker with a 50W RMS rating will be stated as 100W Program. This is not always exact though, and you may see a speaker rated say 300W, that has a program rating of 750W.Program power is double the RMS rating. It was created specifically to help buyers match the power of speakers to a suitable amplifier back in the 80s.You would buy say an 800W RMS amplifier, and 800W Program speakers, and be safe knowing your amp would have plenty of reserve power for the speakers, helping to avoid clipping issues.

Peak Power

Commonly used in the power amplifier and active speaker markets, Peak Power is the maximum that a power supply can produce, or speaker can handle for a very short time. Usually a surge, right before it dies. It's often given as four times the RMS value, but manufacturers can inflate this sometimes to six times the RMS.So for example, a 100W RMS speaker will be given a Peak Power rating of 400W or even 600W.

In reality, it's a total nonsense figure, as it has nothing to do with the performance available, just what it can manage for ten seconds before frying itself, or shutting down if its decent enough to have inbuilt protection.

Max Power

Another favourite of budget speakers and amplifiers to boost numbers. The Max Power rating is taken as a measurement of the maximum amount of power that can be sustained without damage.

Now while this is better than Peak, it's still a big exaggeration on the actual comfortable running performance of the amplifier or speaker. Similar to Program, it's usually given as twice the RMS value, though has no set test values so this figure can be altered by manufacturers to suit marketing.

So for example, an amplifier with 2x 150W RMS rating will usually have a Max Power of 2x 300W, or will often be stated as a 600W amp.

IPP - Instant Peak Power

Ah...IPP… The most magical of figures. Apparently based on the idea that the power supply can somehow manage to double its Max figure for the brief moment before it melts, with the maths involved being rounded up to look nice on a label.

So we take an active speaker. 400W RMS rating. We double that figure for the Max, so that's 800W Max per speaker. They then double that for a Peak of 1600W. Then those are added together and you're given an IPP of 3200W for the pair.

This figure can be ‘adjusted’ to give a nice rounded number, with certain amplifiers currently on the market stating an IPP of 5000W, when their actual power is 1100W bridged, or 2x 400W RMS into an 8 Ohm load.

It's a completely absurd figure, with no real-world meaning whatsoever, and is the sort of marketing that's sadly used more often than not with audio equipment. The manufacturers are desperate to catch your attention, and heavily inflated power figures appear to be the favourite way.


RMS (Root Mean Square)-The truest figure available for comparing speakers and amplifiers electrical capabilities.

Music Power -x2 the RMS

Peak Power -x4 the RMS

Dynamic Power -x2 the RMS

Program Power (PGM) -x2 the RMS

PMPO (Peak Music Power Output) -x4 the RMS

Max Power -x2 the RMS

Total System Power -On a stereo system or amp and speaker package, the total system power is the max ratings of the separate components, all added together. Another useless figure with no real-world meaning.

IPP - Instantaneous Peak Power -This is double the Max power rating, with a little wiggle room to make it even bigger if needed. If you see an IPP rating on an amplifier or speaker, dividing that number by 5 will get you to the approximate RMS.

IHF Power - Instant High Frequency Power -Exaggerated rating taken as a measurement using a 20 millisecond tone burst. Another utterly pointless figure, measuring the system on the point of permanent damage and stating it as an operating figure.


It should be fairly apparent that the audio industry likes to stretch the truth slightly on amplifier and speaker performance figures. Though this is more common on lower powered budget equipment, it most certainly does not vanish as the price rises.The other thing to take into account is that even a true power rating such as RMS is not a sign of musicality or sound quality, it's simply a measurement of the equipment’s electrical capability.

For amplifiers, THD (distortion) ratings, Signal to noise ratio, Input sensitivity and frequency response all present to you additional information to suggest how well the system should perform, and should be taken into account.

With speakers, the RMS is handy again as a true reflection of its power handling, but again that's just its ability to deal with an electrical signal. Realistically a far more important figure is the SPL level, and the Input sensitivity.You can have a 300W RMS speaker, but if its SPL is only in the 70s then its mechanically restricted from cheap components, and will never sound great. If its sensitivity is low (under 85dB) then it's going to require a huge electrical effort from your amplifier before you even get any sound.This is the classic cheap Hi-Fi situation, where the volumes already halfway up before the music is at an audible level.

Knowledge is Power!

It's an old phrase, but holds true, especially with the broad selection of audio equipment on the market.You really need to do your homework so as not to be sucked in by marketing speak and flashy sales techniques, and choose the equipment that's best for you by the use of real world facts and figures.

As you will have gathered, the RMS figure is the one you want. It will give you the best figure for comparing the rated performance of different amps and speakers. You can use the list featured earlier to find the RMS on any equipment by dividing the power figure by the stated amount.There is of course another great comparison between PA equipment, which is to audition it in person at a specialist retailer. Numbers and figures are very useful, but personal taste and sonic nuances in sound reproduction cannot be expressed on paper. So, if possible, always try before you buy!

The team at ElectroMarket are on hand to help you with any enquiries, technical questions and help with selecting the best products for your needs. Our online store is stocked with a selection of speakers and amplifiers for you to discover. Buy in confidence online, with live chat advice available, and phone support both pre and post-purchase.

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