How we test wireless, smart and Bluetooth speakers

Which? tests things properly. We test speakers at our professional audio lab using dedicated experts in the field, and we don't take advertising. Our recommendations are independent, with no bias, big-brand marketing or hype.

We test everything from high-end multi-room speakers to portable Bluetooth speakers that could fit in your pocket, and we put each through the same rigorous assessments.

Our expert lab combines listening-panel expertise with technical testing of the audio equipment for our in-depth sound quality ratings. We also rate battery life and how easy a speaker is to use, plus we explain any useful extra features.

To find the very best speakers on the market, head straight to our expert wireless and Bluetooth speaker reviews, or read on to really get to know how our tests work.

Sound quality: does the speaker make the most of your favourite tunes?

Unsurprisingly, sound quality is the most important factor of any speaker. In fact, if a speaker's audio quality isn't up to scratch, then it can't be a Best Buy, no matter how simple it is to use or how many extra features it has.

We entrust our sound quality tests to audio experts with decades of experience from a variety of backgrounds, including speaker research and development and sound engineering. Their ears are some of the best in the world when it comes to assessing music sound quality.

Our audio experts listen to numerous songs and pieces of music across different genres. Some are designed to highlight a different aspect of sound quality, such as bass, mids and treble, while others are aimed at revealing how accurate and detailed the speaker is.

It's not all subjective, though - our frequency-response tests analyse how much of the audio spectrum the speaker can replicate. This tells us how deep the bass can go, how high the treble will go and how detailed the sound in these extremes will be.

What separates a good result from a poor one?

When you've only been exposed to a handful of speakers, you don't have the breadth of comparative knowledge to fully understand what's good and what's bad, but our lab audio experts do. And when they hear bad sound, they aren't shy about telling us. Weaker speakers sound just that... weak. They lack depth, dynamism and energy, so music sounds flat and often unbalanced, with too little bass to offset the treble.

Top-tier speakers will sound rich, engaging and warm. Every part of the mix will be evident, from the quietest melodies to the punchiest bass.

Martin Pratt, Which? principal researcher and writer, says:

'The enormous range between speakers, vast number of brands and varying tastes, means the wireless speaker test is one of the most challenging. 

After years honing it and working with one of the best listening panels in the world, I'm confident that when we say a speaker is a Best Buy, you'll be bowled over by its sound quality.'

Ease of use: is the speaker simple to control?

Slotting in a CD or laying a vinyl on a turntable couldn't be simpler, and nor should getting your tunes to come out of your wireless speaker, whether it uses wi-fi or Bluetooth.

Our audio experts have tested hundreds of speakers and know what to look out for. We expect clearly labelled buttons on the device, so you don't need to reach for your phone every time you want to change the volume or pause the music.

We run each speaker through everyday scenarios, including how easy it is to set up and connect to your devices – be it Bluetooth, wi-fi or via a cable. We also look at everyday and advanced functionality, including how clear the instruction manual is and whether the control app or equaliser are intuitive.

For wi-fi speakers, we also assess how easy it is to create a multi-room speaker system, and we conduct technical checks on the stability of all wireless connections to ensure there are no issues.

What separates a good result from a poor one?

Not all speakers need a companion app but if they do, we expect them to be snappy and not laden with awkward definitions that require a level of expertise approaching our test experts to understand. 

Better speakers will have clearer buttons and not too many that require multiple presses to perform different functions. Backlit is best, so you can see them in the dark, but they should at least be embossed or clearly labelled, so you can tell them apart easily.

Battery life: how long does the speaker last between charges?

Manufacturer claims and our own battery-life measurements don't always align, which reinforces how important it is that we test the battery on any speaker that has one. 

We continuously play music at a moderate volume to best reflect how you'd use it at home or outdoors. The difference can be enormous – some speakers can't hit the five-hour mark, while others exceed 40. And don't assume smaller models will need more charging. 

Yes, they have a smaller battery, but the smaller speaker means they need less power to run. 

What separates a good result from a poor one?

You don't have to be an expert to figure this one out. When you've got speakers that last more than two days next to some that only just exceed two hours, you can clearly see where the problem is.

Typically, we think around 12 hours is enough for a speaker to score well. 

How we calculate the scores

Olivia Pratt, Which? scientific adviser, says:

'Every test we do contributes to an overall score, and we give more weighting to some tests that are more important to the overall quality of the products.

I'm always looking at the data we get from the lab and seeing how that relates to how people use their products. Sound quality is far and away the most important aspect of a speaker, so it counts for a greater proportion of the score.'

Home speaker 

• 65% sound quality
• 25% ease of use
• 5% energy efficiency
• 5% features

Large battery-powered speaker 

• 60% sound quality
• 25% ease of use
• 10% battery life
• 5% features

Portable speaker

• 45% sound quality
• 25% ease of use
• 20% battery life
• 5% features
• 5% portability

Smart displays and small smart hubs

• 35% sound quality
• 55% ease of use 
• 5% energy efficiency
• 5% features

How do we choose products?

There's a huge variety of audio brands, ranging from the ultra-high-end brands making speakers that cost six figures to the suspiciously cheap ones on Amazon selling speakers for less than £20.

Determining exactly what to test when there's so much choice can be challenging, so we focus on speakers that are more widely available and from brands people know.

That doesn't mean we don't occasionally dip our toe into the sea of cheap Amazon and eBay speakers though, and we've been pleasantly surprised by one or two in the past.

We also aim to cover a wide range of sizes, from huge suitcase-size party speakers, to tiny ones you fit in your pocket, as well as wi-fi ones for the home and smart displays, such as the Amazon Echo.

Which? market analyst, Finn Rainbird, says:

'My aim is that everyone who comes to Which? looking for a speaker, will find one that suits their needs. Whether it's students looking for something for parties or their parents looking for something more versatile for the home. 

That's why I pick speakers from a wide range of different brands at all different sizes.'

Is it a Best Buy wireless speaker? What our verdicts mean

Our speaker tests fall into four categories, to make sure we're not comparing speakers that are wildly different.

Best Buy wireless speakers

A Best Buy speaker has impressed us. It sounds fantastic, is simple to use and, in the case of portable speakers, has a lengthy battery life.

• A wireless speaker for the home needs to score at least 73% to be a Best Buy speaker.
• A large Bluetooth speaker with a battery needs to score at least 73% to be a Best Buy speaker.
• A portable Bluetooth speaker (weighs less than 1kg and doesn't measure more than 20cm in any direction) needs to score at least 68% to be a Best Buy speaker.

Great Value wireless speakers

To qualify as Great Value, a speaker needs to sound good, score at least 60% and cost 20% less than the average price of a speaker in its category, such as home or Bluetooth. Great Value speakers can be Best Buys, too, if they're cheap enough

Don't Buy wireless speakers

Don't Buy speakers are the opposite. These speakers sound flat and dull, and are a faff to set up, connect to and control. Steer well clear.

Our wireless speaker experts

Choosing what to test, deciding how to test and turning those results into reviews and advice is a team effort.

We're consistently looking for new ways to improve our tests and adapt to changing speaker technology.

Meet the team:

• Principal researcher and writer, Martin Pratt: Martin works across TVs, speakers and soundbars, and he brings his audio-visual expertise to every review and advice guide you'll read in the wireless speaker area.
• Market analyst, Finn Rainbird: Finn is tuned into what all the main brands are up to. He makes sure we're testing the right products as close to launch as possible, so you've got speedy reviews for your shortlist.
• Scientific adviser, Olivia Pratt: Olivia is the brains behind our test programme and evaluation, creating up-to-date tests and instructing our labs on what to check, so our results are as comprehensive as possible.
• Tech and cars editor, Will Stapley: Will makes sure we're covering the right topics and answering the right questions, so our guides and reviews are relevant and useful. He's always on the lookout for new ways to showcase our testing and make clever use of our data.