The crossover frequency provided in the speaker design.
A crossover is installed exclusively in a multi-band model (see "Number of Bands"). This is an electronic filter that ensures the division of the incoming audio signal into separate frequency ranges and directs each range to "its" set of speakers. And the crossover frequency shows where the boundary between these ranges lies. If there are more than two bands, there will be several such boundaries: for example, for a four-band system it may be specified "0.15 / 0.8 / 2.8 kHz" or "0.12 / 1 / 3.8".
In most cases, this parameter has mainly a reference value: the frequencies of the built-in crossover are selected to match the operating characteristics of the speakers installed in the speaker system.
The presence or specific version of the
Bluetooth module installed in the speaker system.
The most common way to use such a module is to broadcast sound from smartphones, tablets, laptops and other Bluetooth devices to acoustics. The main convenience of such a connection is obvious — it is the absence of wires and the corresponding freedom of movement, especially since the Bluetooth range is usually at least 10 m (within line of sight). However, note that without special technologies, the audio signal during such a transmission is highly compressed, which affects the final sound quality; so aptX support is required to achieve good quality (see below).
In addition, Bluetooth can be used for other purposes; the most popular option for such an application in the AU is remote control from an external device. However, such features are much rarer.
As for different versions of Bluetooth, they differ both in terms of bandwidth and accessibility. Here is a description of the different options used in the AU.
- Bluetooth v2.0. The oldest of the versions found nowadays. Provides only basic capabilities and up to 2.1 Mbps communication speed, and is also much more prone to compatibility issues than newer standards. Therefore, this version can be found mainly among frankly outdated acoustics.
- Bluetooth v2.1. An updated version of the 2.0 standard, which received a number of improvements regarding the compatibility of...different types of devices and connection security. It is a kind of "classic of the genre", all newer generations of Bluetooth are basically v2.1 plus various additions and improvements.
- Bluetooth v3.0. A version in which a high-speed channel of 24 Mbps was added to the basic capabilities of Bluetooth 2.1 — for exchanging large amounts of data. At the same time, the Bluetooth module automatically determines the amount of transmitted information and selects which connection to use — regular or high-speed.
- Bluetooth v4.0. A fundamental update (after version 3.0), which introduced another data transfer format — Bluetooth Low Energy (LE). This protocol is designed mainly for miniature devices that transmit small amounts of information. Nevertheless, it allows you to significantly save energy when working with larger equipment, such as speakers — in particular, the energy costs for transmitting small service data packets are reduced.
- Bluetooth v 4.1. Development and improvement of Bluetooth 4.0. One of the key improvements was the optimization of collaboration with 4G LTE communication modules — so that Bluetooth and LTE do not interfere with each other. So if a 4G smartphone is often in close proximity to Bluetooth speakers, it is desirable that these speakers have a module with a version of at least 4.1. Another interesting innovation is the ability to simultaneously use a Bluetooth device in several roles (for example, to remotely control an external device while simultaneously streaming music to headphones). However, this point is more relevant for signal sources than for speakers.
- Bluetooth v4.2. Further, after 4.1, the development of the Bluetooth standard. It did not introduce fundamental updates, but received a number of improvements regarding reliability and noise immunity, as well as improved compatibility with the Internet of Things.
- Bluetooth v5.0. Version introduced in 2016. One of the key innovations was two special modes of operation of Bluetooth low energy: speed up mode (by reducing the range) and long range mode (by reducing the speed). In addition, a number of improvements have been introduced regarding the simultaneous operation with numerous connected devices.
The total weight of all components of the speaker system.
