Why does one speaker discharge faster than the other?

The release of the Apple AirPods democratized TWS wireless headphones. But by nature, its products work differently than other Bluetooth devices, such as headphones. Therefore, power consumption varies from one earphone to another. What are these peculiarities? What is the impact on daily life? We tell you everything.

Everyone has only been looking forward to the iPhone 15 since Apple’s keynote on September 12, 2023. A smartphone with great new features, but also inherited from its oldest. In particular iPhone 7It is the first phone of the brand that does not include a 3.5 mm jack port. At the time, Apple wanted to push the concept of wireless audio. And what could be better at this than the AirPods, the first generation of which was unveiled with the iPhone 7. The AirPods, the third generation we tested, are part of the TWS (short for True wireless stereo), small wireless devices for listening to music. Today, this format has become popular. You find them in the catalogs of all smartphone manufacturers and all audio brands.

Also Read – Huawei Nearlink: The technology that can crush Bluetooth will arrive on September 25

This format is very popular today, because it is practical, discreet and does not require a connection port (USB, Lightning or 3.5 mm jack). Simply pair them via Bluetooth with any modern smartphone (and install an app for updates if your headphone brand is different from your phone’s). However, you must have noticed that the format of the TWS earphones is quite small. As a result, the battery is also small. Of course, autonomy is limited.

Why do one earbuds in a pair of AirPods discharge more than the other?

The autonomy of TWS headphones generally ranges from 4 to 8 hours depending on the models, the compatible Bluetooth version, the quality of the audio tracks and whether active noise reduction is activated or not. But you may have also noticed that the battery life isn’t identical between the two earbuds: one often stops before the other. The difference is not huge (less than half an hour), but it is significant. Why ? The reason is rooted in the way the headphones connect to the smartphone.

Let’s start with Bluetooth. This is the famous protocol that allows two products to be linked together. It has been present in all smartphones for more than 10 years. This protocol only manages communication (Automatic recognition, activation, data transfer and deactivation). It does not manage the data type or prop behavior type. For this, there is “Personal files” (which refers to the type of accessory for the smartphone, here a pair of headphones) and Coding software (which refers to the format of the content, here the music). Obviously, it is possible to associate several profiles (headphones, hands-free kit, etc.) and several codecs (simple stereo, high-definition, spatial audio, etc.) to the same device.

The difference in independence is related to the nature of communication

Bluetooth technology has a special feature: the connection is established between one device and another. no more. The device can take advantage of several simultaneous connections (between the smartphone and two different accessories). But each connection is separate from the others. In the case of a headphone or speaker, the phone sends a stereo signal that is received by a single device containing both speakers. On the other hand, in the case of TWS headphones, there is Two speakers physically separated One from the other. There is only one stream to transmit.

To solve this technical dilemma, there is a “simple” tip: Use one of the two speakers as a “master”. This receives the stereo stream coming from the smartphone and then redistributes the information of interest to the secondary earpiece. Thus, each speaker has its own mono stream for a stereo result. Naturally, this means that one speaker does more than the other: only one decodes its mono stream, while the ‘master’ must decode its stream, but also separate the information from the individual stereo stream.

The difference in battery life between the two headphones can be up to 10%.

Extra work also means extra energy consumption. This explains the difference in battery life between two TWS earphones in the same pair. The difference is about 10%. Note that for modern premium products, each earbud in the pair is capable of being the main one. In this case, the headphones switch roles to rebalance their power consumption towards each other. This is why the difference in battery life between the two headphones in certain pairs may be very small. Role change is managed automatically or based on the first earbud you put in your ear.

Obviously, using one of your headphones as a bridge doesn’t just impact the headphones’ battery life. This also affects latency: you notice a delay between the time you see an event on the screen and the time you hear it. This latency is especially felt with games. In the best case scenario, the latency is up to 32 ms. at worst, This can be up to 300 milliseconds. Compare figure with 5-10ms latency for a wired headset. It depends a lot on the codec you use, but also on the distance between the smartphone and the headphones.

Auracast: the Bluetooth technology that will solve all problems?

Bluetooth 5.2, which became official in 2020, provides an answer to this problem. In fact, this update introduces the concept of Auracast. This technology allows multiple products of the same nature to be connected to the same device simultaneously. This could be several headphones, for example, for sharing music. It can also be two speakers of the same pair, with each speaker managing its own audio stream reception itself.

The advantage of this technique is twofold. Firstly Then the energy consumption becomes “homogeneous”.. The headphones will then have the same continuous autonomy. Then the latency for players will be reduced. This is still a very high rate, even if the arrival of Bluetooth LE Audio has had a very positive initial impact on this issue. These are two great benefits, with one limitation: the smartphone and headphones must be compatible…