XiaomiRedmi Buds 4 Pro

How we test sound quality

We rate sound quality using a professional panel of expert listeners with a range of ages and musical tastes. They listen to samples that cover a wide range of music and radio genres, giving a rating per recording and an overall verdict.

How we test microphone quality

We test the quality of the speech picked up by the microphone on the product. We test it with and without background noise to come up with a verdict.

How we test noise cancelling

We use an artificial ears to measure the exact sound measurements being stopped by the noise cancelling features on each pair of headphones. We will enable active noise cancelling (ANC) if the headphones have this function. This a premium function and these products monitor surrounding noise and alter the strength of noise-cancelling to combat it. Our acoustic seal test tests headphones with ANC to see how well they physically block out noise cancelling without playing any audio.

How we test comfort

Our professional panel of listeners assess the comfort of the product.

How we test durability

Our lab professionals assess how well built the headphones are. We drop the products onto a stone floor from a height of 1.8 metres to test their robustness. We also put them through identical rain tests for five minutes to see if they are water resistant.

How we test battery life

We play sounds continuously at a reasonable volume until the battery runs out. We replicate how you are likely to use the headphones, such as with noise cancelling enabled. Since wireless headphones are convenient, battery life doesn't affect our overall score for a pair of headphones (although anything particularly bad we'd make a Don't Buy).