What is PMPO in home theater?

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What is PMPO?

PMPO is an abbreviation for "peak music power output", which is a marketing term typically used in the description of home theater systems. This figure refers to not only the maximum wattage of the speaker's main drivers (the tweeter and the woofer) but also takes into account other speakers like the subwoofers. Therefore, home theater systems are advertised with high PMPO because it then gives the impression that the system is capable of delivering the "wattage" and loudness.

The term PMPO is designed to get the attention of buyers, because the human ear is capable of ignoring low bass frequencies, which are then perceived to be high-volume sounds, even at very low levels. So if the woofer and the satellites in the 5.1 speaker set have wattage of 140 watts each, the PMPO for that system would be 140 watts. Basically, manufacturers do this because PMPO is an easy way of selling sound systems to consumers.

Is PMPO worth paying attention to?

For most people out there, purchasing a home theater system can be a confusing and lengthy process. There’s all sorts of different components to look at and contemplate. One of the most important things to focus on is the total wattage of your system and the type of amplifier it comes with. “Power,” or “RMS power” (root mean square power), is measured in watts. It’s a measurement of the average power output over a period of time.

One of the most common specs to look at with amplifiers is the total power output, commonly referred to as the “power,” or the “power rating.” It’s written as PMPO. PMPO is the property measurement of the maximum power output of an amplifier. It’s the sum of the RMS power ratings at any point in a sine wave. PMPO is essentially the amount of power that the amplifier can put out in real time, at any one moment in time. “Real World” power, is the amount of power the amplifier can put out over long periods of time.

As you might have guessed, PMPO is a marketing term.

What to use instead of PMPO?

Also known as Peak Music Power Output, PMPO is used to measure the maximum wattage of a speaker.

We prefer Sound Pressure Level (spL) for two reasons. The first reason is it’s more relevant and appropriate because we hear sound pressure levels at our ears, not watts.

The second reason is that we want to use measurements that are relevant to our hearing. A watt is a measurement of power, which is not relevant because the objective is to deliver sound levels we can hear. A sound pressure level is a measurement of pressure, which we do hear. Because we are trying to deliver sounds that we can hear, sound pressure level seems like a more appropriate criteria.

Some manufacturers have started using the terminology Sound Pressure Level, which is preferred. But, if your product specification sheet lists the PMPO, you can rest assured that you should expect the product to be able to deliver maximum sound pressure levels that are compatible with that number.

Choosing the right speakers based on power

If you’re shopping for home theater speakers, you’ve probably come across a rating known as power handling. If you ignore this rating, you may end up with a speaker system that produces distorted sound or has damaged drivers.

The power handling rating is used to establish how much juice a speaker component can handle. If your home theater receiver features speaker level inputs, the power rating may appear on the speaker terminal. If it’s present, it will either be listed in watts or as Continuous Average Power/Peak Music Power (C.A.P/P.M.P).

The Continuous Average Power or C.A.P (sometimes P.M.P) rating is the average amount of amplified power the speaker can handle safely at a specified distortion level. This rating applies to all four channels when operating at full level. If you never listen at full volume, it’s possible that two channels may handle the rated power. This is important when picking a home theater receiver. Ideally, your receiver should have enough power to drive all of the speakers at peak for extended periods of time without failure.

It’s important to note that the combined rating of the speakers should be less than the output power of your receiver.

Your amplifier’s power

Output rating, in watts.

The PMPO is an acronym for ‘peak music power output’ that many manufacturers use to describe a home theater amplifier’s power output. It is similar to the RMS measurement, but instead of measured over the course of an entire song, it is measured in watts at the peak volume of a song. This measurement is generally used only for amplifiers that have at least 100 watts of power.

The PMPO rating is quite misleading for consumers because it doesn’t tell the whole story about the amplifier’s output power. It only gives a snapshot of the amplifier’s output power during a specific moment, which may not always be reflective of its power output over the course of a song.

Stereo or surround sound

Most home theater systems today have multiple speakers to reproduce the sound from the movies they play. A speaker plays sound in every direction and has different specifications from others. A speaker’s performance is often described using the term “watts” or "power handling" and its loudness using the term "speaker sensitivity". These two terms concentrate on the speaker itself with PMPO used to describe the speaker's ability to work together with the receiver, subwoofer and other speakers to create a surround sound experience.

The PMPO rating more strongly reflects the power and range of a speaker system's bass rather than the higher frequency treble or midrange. A speaker system that is rated at 180 watts, for example, will get louder than one that is rated at 170 watts. A 180 watt speaker system will also be able to achieve a lower bass frequency.

The greater number of watts your surround sound has, the better it can reproduce sound from a variety of devices. For example, a movie with a heavy bass sound or where explosions detonate will push the speakers to the max and require a greater number of watts to fully enjoy the sound.

Generally, larger speakers, such as floor-standing speakers, will have a higher PMPO rating than smaller speakers, say bookshelf speakers. This is because the larger speakers can handle more power and also reproduce a lower bass sound.

The size of speakers

Most people know that the louder a speaker can get, the better. But there is a limit to how loud a speaker can be and how much power it needs.

A problem arise when you decide to increase your speakers for price or size. For example, a speaker that has double the size usually means that it can produce an extended frequency response and enhanced bass, but it also mean double the price.

It’s the same for power, too. A speaker or amplifier with twice the power can produce double the sound level or voltage level. On the other hand, doubling the power will also double the size, weight, and price.

The bottom line is that you need to consider the source of the sound and the size of the room you’re trying to cover.

In home theater, the PlayStation Portable (PSP) is a great sound system on the go. It comes with great speakers that are rich and full and give you surround sound from such a tiny device. A great stack of built in speakers, the PSP produces rich, full sound and plays music that is hard to distinguish from CD.

The PSP has a maximum power of 200 milliwatts per channel. With this, you can connect the PSP to a pair of speakers and start building your own portable sound system.

Some final thoughts

The PMPO rating (sometimes abbreviated as RMS) can be misleading because it can be first used to compare one subwoofer to another. For example, you can say that a 20" speaker has a PMPO rating of 250W but a 10" speaker has a PMPO rating of 300W.

But you can't really compare sound pressure levels between speakers since they're two completely different things. Sound pressure levels are measured with a decibel meter, while the power measurement is based on a sine wave.

In fact, there's a more appropriate rating called impulse measurement that can more clearly show you how loud the subwoofer can play at its maximum. This measurement, along with other speaker characteristics, are provided by the manufacturer and are much more credible in terms of comparison.

Finally, the sensitivity rating and RMS rating are also two different characteristics that are very important when you're purchasing a speaker. Not all speakers with high sensitivity have a high RMS rating and the converse is also true.

The goal of researching the speaker's RMS (or its PMPO rating) should be to then research all of the other characteristics as well. You want to do enough research to determine the speakers in question are best for you, and your friend, and your significant other who's a music snob.

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