Comparison Sony Extra Bass SRS-XB21 vs JBL Flip 4

Speaker system impedance to alternating current. Impedance matters primarily when connected to an external amplifier: if the impedance of the speaker system is less than that of the amplifier, distortion in sound is possible, if it is greater, the acoustics may sound quieter than we would like.

The total power of all channels of the speaker system. The higher the power, the larger the size of the room in which the audio system can be used, however, more powerful portable speakers usually have larger dimensions and weight.

The range of audio frequencies reproduced by the audio system. The wider the range, the richer the sound, the more details the speakers can convey, especially in the low and high frequencies. At the same time, we note that the average human ear is able to hear sounds in the range of about 16 – 20,000 Hz, and it makes no sense to provide a wider range in speakers — a person simply will not hear it. Also note that a wide frequency range alone does not guarantee good sound quality.

Initially, sound transmission via Bluetooth provides a rather strong signal compression, which can greatly spoil the impression when listening to music. To eliminate this shortcoming, various technologies are used (the most popular of which is the aptX codec). Of course, to use any of the technologies, it must be supported not only by acoustics, but also by the Bluetooth device with which it is used.

— aptX. A Bluetooth codec designed to greatly improve the quality of Bluetooth audio. According to the creators, it allows you to achieve quality comparable to Audio CD (16-bit/44.1kHz). The benefits of aptX are most noticeable when listening to high-quality content, but even on regular MP3 it can provide a noticeable improvement in sound.

aptX HD. This codec is a further development and improvement of the original aptX technology, which allows you to transmit sound in even higher quality — Hi-Res (24-bit / 48kHz). According to the creators, this standard allows you to achieve signal quality that is superior to AudioCD, and sound purity comparable to wired communication. The latter is often questioned, but it can be argued that, in general, aptX HD provides very high sound quality. On the other hand, all the advantages of this technology become noticeable only on Hi-Res audio — with a quality of 24-bit / 48kHz or higher; otherwise, the quality is limited not so much by the characteristics of the connection as by the prop...erties of the source files.

aptX Low Latency. A specific variation of the aptX described above, designed not so much to improve sound quality, but to reduce delays in signal transmission. Such delays inevitably occur when working via Bluetooth; they are not critical for listening to music, however, when watching videos or playing games, there may be a noticeable out of sync between the image and sound. The aptX LL codec eliminates this phenomenon by reducing latency to 32ms, a difference that is imperceptible to human perception (although it is still too high for serious tasks like studio work with sound).

— AAC. A codec used primarily in Apple portable technology to improve Bluetooth audio. In this sense, it is similar to aptX (see relevant paragraphs), but noticeably inferior to it in terms of capabilities: if the sound of aptX is compared with Audio CD, then AAC is at the level of a medium-quality MP3 file. However, this is quite enough for listening to the same MP3s, the difference becomes noticeable only on more advanced formats.

— LDAC. Sony proprietary Bluetooth codec. In terms of bandwidth and potential sound quality, it surpasses even aptX HD, providing performance at the Hi-Res level of 24-bit / 96kHz sound; there is even an opinion that this is the maximum quality that it makes sense to provide in wireless headphones — further improvement will simply be imperceptible to the human ear.

— Speakerphone. The ability to use portable acoustics as a hands-free system for a mobile phone. In this mode, the acoustics are connected to the device via Bluetooth, and the voice of the subscriber at the other end of the line is output not to the phone speaker, but through the speakers of the acoustic system. This is often more comfortable than holding the phone to your ear; in addition, the speakerphone is useful if several people need to participate in a conversation.

— NFC. NFC is a short-range wireless communication technology (about 10 cm). It allows for many uses, but in portable acoustics it is usually used as an addition to Bluetooth, which makes it easier to set up a connection. For example, a smartphone with an NFC module can simply be brought to a speaker with the same function — and both devices will automatically recognize each other, while the user will only have to confirm the connection.

— Multipoint. A technology used in Bluetooth models that allows the speaker to connect to multiple devices at the same time. Thanks to this, you can, for example, listen to music from a laptop, and when a call is received on a mobile phone, switch the acoustics to a conversation. This technology has its own characteristics for different manufacturers, and therefore, if the multipoint function is critical for you, you should separately clarify the details of its operation in the se...lected model.

— Synchronization of speakers. The model supports the ability to synchronize the operation of several speakers connected to one signal source. This solution allows you to realize truly stereo sound, improve the quality and power of sound reproduction, as well as expand the stereo panorama. The only thing is that both speakers must support the appropriate connection type. Different brands may have their own speaker interconnection technologies (JBL Connect, JBL PartyBoost, Sony Party Chain), or maybe a universal TWS.

— Vibrocolumn. A kind of portable acoustics that uses external objects as a sound emitter — tables, window panes, etc. In simple words: in order for such a column to sound, it must be fixed on another object. However not all of them require fixing on an external object — some practically do not differ from ordinary portable acoustics, and the “vibration” function is provided as an additional option in them.

— Light effects. Such effects can be different — from the simplest set of light bulbs flashing at a constant frequency to advanced colour and music systems that produce multi-coloured patterns in time with the music being played. Anyway, this function carries more entertainment meaning and does not affect the sound of the device.

— Mini-Jack output (3.5 mm). A connector designed to output an audio signal from a speaker system to another device — for example, a stationary audio system with a mini-Jack (3.5 mm) line input. Note that the signal level at this output is low, and it is impossible to connect passive acoustics directly to it — you need to use an amplifier.

— For headphones (miniJack 3.5 mm). A specialized headphone output, made in the 3.5 mm mini-Jack format — this is the standard used by the vast majority of modern "ears". Headphones can come in handy in a situation where loud sounds are undesirable (for example, in a living room at a later time) — or vice versa, in noisy environments where the sound from the speakers is simply not heard.

— Hours. A traditional clock is a device for displaying time. They are not a "vital" function for portable acoustics, but in some cases it is faster to look at the time on the speaker's dial than to look for another clock.

— Alarm clock. Classic alarm clock — a sound signal at a user-defined time, which can be used both for getting up and for other purposes. Must be combined with a watch (see above). The specificity of alarm clocks in portable acoustics is that they allow you to use a certain song or even a radio station as a signal.

Theoretically, a higher capacity allows to achieve greater battery life, but in fact, the operating time also depends on the power consumption of acoustics — and it can be very different, depending on the characteristics and design features. So this parameter is secondary, and when choosing it is worth paying attention not so much to the battery capacity, but to the directly claimed operating time (see below).

The time it takes to charge a fully discharged device to 100% charge.

The main material used in the construction of the hull.

— Plastic. Inexpensive and at the same time very convenient material for portable acoustics. Plastic easily accepts a variety of colours and complex shapes; the latter not only gives space to designers, creating speakers of unusual design, but also allows you to apply various tricks to improve sound quality. In addition, this material is not afraid of moisture. It is believed that the strength of plastic is not very high, but this disadvantage is easily compensated by the large thickness of the material or the use of special impact-resistant grades. Therefore, plastic is found in all categories of speakers, from low-cost to high-end and from "home" to extreme, designed for an active lifestyle and frequent outdoor use.

— Metal. The metal gives the speakers a solid and expensive appearance, and on the practical side, this material is remarkable primarily for its high strength. At the same time, it is much more expensive than plastic — also due to the fact that manufacturers have to use shock-absorbing inserts and other tricks to avoid an unpleasant "metallic" coloration of the sound; and the mentioned strength is most often not critical. Therefore, metal cases are much less common than plastic cases, mainly in rather expensive portable acoustics.

— Silicone. Relatively soft and ela...stic material, not afraid of moisture. Suitable for creating dust, moisture and shock-proof speakers; in addition, it is convenient for models with suction cups (see above) — the part of the body that has the appropriate shape can play the role of a suction cup directly. At the same time, silicone has no other noticeable advantages over plastic, so its use is limited to specific models of portable acoustics.

— Rubber. For a number of reasons, rubber is considered well suited for models with dust and water protection, almost all speakers made of this material are protected. In addition, due to the softness of the rubber provides good shockproof properties.

— Wood. Wood is considered the optimal material for speaker cabinets in terms of acoustics. However, the specificity of portable speakers is such that this moment is not decisive in this case, and the main advantage of wooden cases over others (primarily plastic ones) is their aesthetic appearance, with characteristic colours and patterns. In addition, many consider wood a more pleasant to the touch and “natural” material. But this option does not have any special practical advantages, despite the fact that it is quite expensive. As a result, portable speakers with wooden cases are rare — they are mostly designer models created based on the original design.