Your local drive-in DJ, the next-door neighbour or even your best friend bragging about their new sound system might sound familiar to you. There are plenty of times when I’ve heard them say: “My new speakers are off the charts man, they’ve got 1,500 Watts of power!” This goes to show that a lot of people assume that more power means more volume, but really, it’s not that simple. Sure, a 1,500 Watt speaker is louder than a 10-Watt model but definitely not 150 times as loud. As a matter of fact, sometimes a 1,000 Watt speaker can produce more volume than a 1,200 Watt one. This blog is written to separate the facts from fiction and show you how it really works when it comes to the power capacity of speakers and amplifiers.

How many Watts? - The Truth About Speakers and Power Output

Power Capacity: Giving and Taking

First of all, it’s important to know the difference between the giving and taking of power. An amplifier outputs power and passes it on to a speaker. In turn, the speaker takes the power and processes it. It uses the power to form a signal that’s ultimately reproduced as sound. Even though there are two different types of speakers – active ones with built-in amplifiers and passive speakers – the principle is the same: sound gets amplified. Many people don’t realise this but this is the crux of the matter.

What does “100 Watts” mean exactly?

Because speakers receive power, wattage isn’t something that they ‘have’. Let’s take a 100-Watt speaker for example. Basically, this means that it can handle, or rather, process 100 Watts of power. More specifically, the number of Watts indicate how much power a speaker can be burdened with under certain circumstances before it breaks. In practice, this means that a 100W speaker is often actually able to handle more than 100 Watts.

Differences between manufacturers

This last bit is exactly where things can bottleneck. Each manufacturer uses a different method to measure the amount of power their speakers are able to withstand and it’s often unclear how, but perhaps more importantly, which signal they’ve used for the calculations. Even when boasting the same power capacity, different speakers can come with different results when tested under the same conditions. That means that in real life, the specified number of Watts can sometimes cause more harm than good.

But 5,000 Watts means more volume than 100 Watts, right?

True, but people often make a mistake when they compare speakers to lamps and say that a 100W bulb burns brighter than a 10W bulb. While they’re absolutely right, the comparison is a little more complex and requires some nuance. The specified power output of a speaker isn’t the sole determining factor when it comes to how loud it’ll go. You can’t really compare a 5,000W speaker to a 100W one, simply because the difference is too extreme and doesn’t take other aspects into consideration. Granted, 5,000 Watts will lead to more volume than 100 Watts but if the numbers aren’t as far apart, say, 1,200W versus 1,000W, it might well be that the latter is louder because it comes with superior specifications in other regards. This can’t be overlooked when you’re weighing up the pros and cons of the speakers on your shortlist.

How many Watts? - The Truth About Speakers and Power Output

So what do I look for?

To get a better understanding of how loud a speaker can go, you’ll need to look at a few other aspects.

Sensitivity in dBs

First, the sensitivity. The sensitivity of a speaker is expressed in dBs, or decibels. Usually, manufacturers specify the amount of dBs that a speaker can produce with a single Watt of power at a 1-metre distance. In most cases, the number will lie somewhere between 84 and 92 dB with the rule of thumb being: the more sensitive a speaker is, the less power it needs to put out louder volume. Does that mean that smaller speakers are easier to power? No, because these are often less sensitive than larger units because they are forced to sacrifice a large portion of the sensitivity to reproduce a decent amount of low-end. To shape bass frequencies, a speaker will need to be larger so it doesn’t have to sacrifice as much to remain sensitive. So sensitive speakers certainly aren’t less good than more insensitive ones, as a matter of fact, they’re better! Keep in mind that instead of sensitivity, manufacturers sometimes use the term ‘efficiency’. Different word, same principle.

Maximum sound pressure level (SPL)

The maximum sound pressure level also plays an important role in determining how loud a speaker can go. It’s a way for the manufacturer to tell you how far the sound pressure can be pushed before the speaker permanently breaks down. Unfortunately, however, not every manufacturer includes the maximum dB SPL in the specifications of their gear.

PMPO

Then there’s the PMPO, the peak maximum power output. While it sounds cool, it’s more of an irrelevant theoretical aspect than anything else. This indicates the amount of power a speaker is able to handle for a few milliseconds before it breaks beyond repair. It’s not the most useful of specifications because you don’t exactly want to try this.

How many Watts? - The Truth About Speakers and Power Output

Matching amplifiers and speakers

Now that you know that the wattage doesn’t necessarily indicate how much volume a speaker can produce, let’s eliminate the largest of misconceptions in the world of sound amplification. A lot of people believe that you can’t or shouldn’t match a 100W amplifier with a 200W speaker because you’d risk blowing the speaker up, but au contraire. It’s actually better to use an amplifier with a higher power capacity than that which the speaker can theoretically manage. How so, you ask?

Example

Let’s take a 100W speaker. Some would play it safe by hooking up an amplifier that’ll continuously supply it with 50 Watts of power. This would mean that the amplifier is only able to offer 50W before the sounds start to distort. When this line is crossed, clipping occurs. The threshold is actually a lot lower than most people believe, and trust me, your speakers won’t like it. If the amplifier isn’t powerful enough, it’ll push itself past its own limits and distort the sound to such an extent that the speaker will blow up, with the tweeter going down first because distortion mainly happens in the higher frequencies and causes the voice-coil to overheat. But, if you try really hard, you can probably give the other components inside the speaker a one-way ticket to the scrapyard as well.

More information about matching speakers and amplifiers can be found in our blog on the difference between passive and active speakers.

What have we learned?

The big takeaway here is that while the number of Watts of a speaker shouldn’t be overlooked, it doesn’t tell you how loud a speaker can go. The wattage also doesn’t indicate sound quality or possible lifespan but can be really useful when you’re looking to buy a suitable amplifier. Just keep in mind that it’s better to go with an amp that has ‘too much’ power. To get a better picture of how loud a speakers can sound, don’t just look at the amount of Watts but check out the SPL and sensitivity specifications.

Hopefully, you now feel confident and informed enough to make a choice based on the facts instead of the fiction. Still not entirely sure if that new amp or speaker will work well for you? Simply put your question in a comment below!

See also

» Blog – The Difference Between Active and Passive Speakers
» Blog – How To Connect Your Microphone to a Speaker
» Blog – How to Connect Your Speakers to your Audio Equipment
» Blog – Turning a Speaker Set Into a Fully-Fledged PA
» Blog – Buzz, Hum and How to Get Rid of it
» Buyer’s Guide – How do I Choose the Right Bluetooth Speaker?
» Buyer’s Guide – How do I choose the Right Studio Monitor?

» PA Starter Sets
» Speaker Sets
» Active Full-Range Speakers
» Passive Full-Range Speakers
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