Speaker manufacturers run power tests on their new speaker designs before releasing them to the public.
You can typically check what power tests they have completed on a speaker by looking at the manufacturer’s website. They will state something like “Tested for two hours using a continuous, band-limited pink noise signal as per AES standard”.
In addition, you may see references to continuous power rating or power handling.
But what exactly is a speaker power test? And why do professional speaker companies complete them?
A speaker power test is performed to ensure that a speaker will withstand intended use. It is generally completed to an AES standard and will reveal any durability, mechanical, or thermal design flaws with the speaker.
It is essential that a speaker is power tested before they release the design to the public, as a 2-hour power test can reveal some important technical issues.
In this article, I will cover what a speaker power test is, covering:
- What is a speaker power test?
- How to test a pro audio speaker to AES standards?
- Why do speaker manufacturers power test?
- What is speaker power handling?
- What does speaker power rating mean?
- What do we mean by continuous power?
What Is A Speaker Power Test?
A speaker power test involves feeding a signal into a speaker, which is typically pink noise, for between 2 to 100 hours.
In the pro-speaker industry, a standard power test is generally 2 hours long. We refer to speaker tests which are 100 hours long as longevity tests.
Both tests have the aim of testing the limits of the speaker, both mechanically and thermally.
As mentioned, we typically use pink noise for industry-standard power tests, as this has the dynamics to really test the speaker.
Pink noise sounds more mellow than white noise which has a hissy sound. Pink noise more closely resembles music and is generally very balanced in sound.
By definition, pink noise is described as noise that has the same constant power per percentage bandwidth, per octave, per decade, etc.
Because the pink noise is more dynamic, similar to music, we can stress our speaker under test both thermally and mechanically.
In order to keep some sort of testing standard across the loudspeaker industry, there are industry standards set in place by the AES. (Audio Engineering Society).
Here are the most relevant power test procedures and standards: [source]
- AES2-1984 Standard
- AES2-2012 Standard
- IEC268-5 (1978) Standard
- EIA RS-426-A (1980) Standard
- EIA RS-426-B (1998) Standard
How To Test A Pro Audio Speaker To AES Standards
Let’s imagine you have developed a new speaker driver and you want to power test it.
In very simple terms, here is an example of a power test procedure. In reality, you should have a copy of the AES standard to follow, which will tell you exactly what needs to be done, but the following is a general overview for informational purposes:
- Pick your power for the test. This is generally the nominal power rating of the speaker.
- Pick your frequency range. This will generally change based on the type of speaker being tested. For example, you might test a low-frequency driver in the 45Hz to 500Hz range.
- Pick your pink noise band limit. This will depend on your driver type.
- Pick your voltage. This is generally calculated from the minimum impedance.
- If using AES-1984 standard, your crest factor will be around 6dB.
- The amount of time your power test will run is 2 hours.
- You should carry out the power test in free air, in a normal temperature environment. (For example, an ambient temperature of around 20°)
After your test runs for two hours, you will then need to check your speaker driver to ensure that it has survived.
Generally, we would then sweep a loudspeaker driver with a frequency from 20Hz to 20Kz and check that the speaker operates normally with no rub, buzz, or other faults.
Be careful when handling a speaker after a power test as it will be hot.
Generally, the SPL is remeasured to ensure that the speaker is still operational.
If everything looks good, and the specifications of your rest are met, then your speaker has passed power testing.
Why Do Speaker Manufacturers Power Test?
A speaker power test will reveal some of the following potential problems of a loudspeaker driver, giving a good indication of how it will operate in reality when working in the field.
- A speaker power test can tell us how much power a speaker is capable of using. This is called speaker power handling.
- A speaker power test can tell us how much power will destroy a speaker.
- A speaker power test can cause a speaker to fail thermally revealing design issues.
- A speaker power test can cause a speaker to fail mechanically, revealing mechanical design faults. For example, insufficient suspension excursion, or mechanical interference where a speaker might be driven so hard the voice coil rubs and buzzes or even jumps out of the magnetic gap.
What Is Speaker Power Handling?
A speaker’s power handling is determined by a speaker power test.
Speaker power handling refers to how much power the speaker can handle before burning out.
What Does Speaker Power Rating Mean?
A speaker power rating is the amount of power a speaker can handle, typically over short, intermittent bursts. This rating is usually given in watts.
Speaker power handling is important to consider when choosing a speaker, as it determines how much power the speaker can handle without being damaged.
What Do We Mean By Continuous Power?
When completing a power test, there are different types of power specifications that can be used as part of the test. One of the most common is continuous power, which is part of the AES power testing standard.
For example, you may see a professional loudspeaker manufacturer state something like this on its website, “2 hours test made with continuous pink noise signal within the range Fs-10Fs. Power calculated on rated minimum impedance. Loudspeaker in free air”. [source]
In very simple power test terms, continuous power means they applied the pink noise signal continuously for the entire duration of the power test, with no interruptions.
Final Thoughts
Speaker manufacturers put a great deal of effort into testing their products to ensure they can survive use in the real world. Power testing is one way to safety check, and simulates how a speaker will actually be used in the real world to ensure it can meet real-world application demands.
By completing a speaker power test, manufacturers are able to reveal potential problems with the driver and correct them before releasing the product to the public.
Speaker power testing is a fundamental step in professional audio production with nearly all speaker manufacturers completing some form of standard power test. The AES-1984 standard is one of the most popular power testing specifications with speaker manufacturers in Europe.