Comparison Denon D-T1 vs Pioneer X-CM66D

— Built-in memory. Own memory allows you to store and play music and other content directly using the audio system, without the use of external media (which can become damaged or lost). Such memory can be based on hard drives or SSD modules; the first option provides good capacity at a low cost, the second is faster and more reliable.

— USB port. A classic USB port, which in this case is usually used for flash drives, external hard drives or other devices with a storage function - for example, miniature audio players. USB functionality includes, at a minimum, direct playback, but may provide other capabilities, such as file sharing with the built-in memory (see above). In addition, if necessary, a connected device (for example, a pocket player) can be charged through this port.

- Card reader. A device for reading information from memory cards; Such media are very popular in modern electronics. Most often, card readers are designed for various versions of SD or microSD cards, but other options may also occur; This point should be clarified separately in each case. The purpose of this function is much the same as the USB port described above: it is primarily used for direct playback, but other functions may also occur.

- CD. Having a CD drive means at least the ability to work with d...iscs recorded in the CD Audio format (up to 74 minutes of high-quality audio, divided into tracks). In addition, modern audio systems often provide support for discs with MP3 files; In this format, one disc can accommodate an entire collection of albums, but the sound quality is lower. And sometimes it is possible to work with optical discs in DVD format.

- Vinyl records. Built-in player for playing music from vinyl records. Technically, such media are completely obsolete, but they still have many loyal fans. In addition, many audio systems with this function support recording to USB (see “Advanced”); this may be useful to vinyl owners who want to transfer their music libraries to more modern media.

In addition to those described above, modern audio systems may include other types of media. For example, some models are equipped with USB type B inputs, so they can connect to a computer via a USB connector and work as computer speakers with advanced capabilities (such as copying music from a PC to an external drive or vice versa).

Radio bands accepted by the music centre tuner. To date, the most common support for such ranges:

— FM. Part of the ultra-short wave (VHF) band between 87.5 MHz and 108 MHz. It uses frequency modulation, which allows you to broadcast music in stereo with a fairly high sound quality, as well as transmit RDS signals (see RDS). At the moment, most music radio stations in the CIS broadcast in this range, as a result of which FM is supported in the vast majority of audio systems. The disadvantage of this option is the limited reception area — a maximum of several tens of kilometers from the transmitter — so FM broadcasts can usually be listened to within the same city and surrounding areas.

— AM (from the English amplitude modulation — amplitude modulation) — broadcasting using amplitude modulation. Usually this term means broadcasting on medium waves in the range of 520-1610 kHz; most consumer AM receivers are designed for these same frequencies. The reception range of AM stations can be hundreds of kilometers, but the sound quality is lower than on FM, so this format is broadcast mainly by “talk” and news radio stations.

— DAB+. DAB is an abbreviation for Digital Audio Broadcasting, i.e. "digital broadcasting"; and "+" means an improved version of this standard. Formally, DAB + is not only a range, but also a signal transmission format: unlike all the options described above, it, as the name implies, is digital. This gives a number of advantag...es over traditional transmitters — in particular, a greater range with less power and high quality of the broadcast sound. In addition, this sound is practically not subject to distortion: weak interference does not affect its quality, and when the transmitter power is critically reduced, the signal is not distorted, but disappears entirely. The latter, however, can be written down as disadvantages; but the really significant drawback of this option is perhaps its low prevalence (so far) in the CIS countries. Technically, such broadcasting can be carried out in any band above 30 MHz, but in fact several options are used (depending on the country) related to the VHF band. Note that DAB+ tuners are capable of receiving original DAB radio broadcasts, but not vice versa.

The term "impedance" refers to the resistance of a speaker system to alternating current. Note that in the case of audio systems, this parameter plays a secondary role: it is important for selecting acoustics for an amplifier, and here both of these components are in most cases optimally matched by the manufacturer to each other. Therefore, in fact, information about the impedance can be useful only when looking for speakers to replace the complete ones: it is highly desirable that the new acoustics have the same impedance as the standard ones.

The total frequency range reproduced by the acoustics of an audio system. Measured from the lower threshold of the lowest frequency speaker to the upper threshold of the highest frequency: for example, in a 2.1 system with main speakers at 100 – 22000 Hz and a subwoofer at 20 – 150 Hz, the total value will be 20 – 22000 Hz.

In general, the wider the frequency range, the fuller the reproduced sound will be, the less low and high frequencies will be lost due to insufficient acoustic capabilities. On the other hand, do not forget that the actual sound quality also depends on a number of other parameters — primarily the frequency response. In addition, human audible frequencies range from 16 Hz to 22 kHz; deviations from these values are very small, and the upper limit also decreases with age. Therefore, from a practical point of view, it does not make sense to provide too large a frequency range; and impressive performances like 10 – 50000 Hz, found in top-class models, are usually more of a kind of "side effect" of high-quality speakers (and at the same time — a marketing ploy) than a really significant moment.

- AirPlay. AirPlay technology was developed by Apple. It is based on Wi-Fi and is used to wirelessly broadcast content from Apple devices to external audio systems. Thus, this function is useful for tech who want to connect an iPhone or iPod touch to the audio system, but do not want to bother with wires; However, it is possible to connect other devices via AirPlay - for example, a PC with iTunes and a Wi-Fi module installed.

- AirPlay 2. The second generation of the AirPlay technology described above, introduced in 2018. Among the main innovations of this version is support for the multiroom format, that is, the simultaneous broadcast of several audio signals to different compatible devices installed in different places. Thus, you can, for example, turn on a radio broadcast of a news program in the living room, relaxing music in the bedroom, etc. In addition, AirPlay 2 received a number of other improvements - improved buffering, the ability to stream to stereo speakers, as well as support for voice control via Siri.

- Chromecast. Original name: Google Cast. Technology for broadcasting content to external devices, developed by Google. Allows you to transmit an audio signal from a PC or mobile device to the audio system; the broadcast is usually carried out via Wi-Fi, while the receiver and the signal source must be on the same Wi-Fi network (with the exce...ption of Chromecast media players). Note that in signal sources (smartphones, tablets, PCs, etc.) Chromecast is implemented at the level of individual applications. For example, at the time of its creation, this feature was available, in particular, in the YouTube and Netflix applications for Android and iOS, as well as in the web versions of these applications for Chrome. Thanks to this format, this technology is extremely widespread these days, and the ability to connect a particular gadget to an audio system with Chromecast is usually limited to the ability to install appropriate applications on this gadget.

- DLNA. DLNA (Digital Living Network Alliance) is a standard that allows you to combine various types of home electronics and household appliances into a single network for content exchange and control. In the case of audio systems, DLNA can be used, for example, to play music from the disk of a computer connected to such a network, broadcast sound to a device installed in another room (for example, an amplifier), etc. Connecting to DLNA can be done either wired or wirelessly (using the Wi-Fi standard), and device compatibility does not depend on their manufacturers - the only condition is compliance with the DLNA standard.

- LAN. Standard interface for wired communication to local computer networks based on the RJ-45 connector. Its presence allows you to use various network functions, such as Internet radio (see "Advanced") or DLNA (see above). Compared to another network interface - Wi-Fi - LAN is less convenient due to the presence of wires, but is more reliable and provides a higher actual data transfer speed.

- Wi-Fi. The presence of a Wi-Fi wireless communication module in the audio system design. This technology is used both in computer networks and for directly connecting various devices to each other; its “range” is sufficient to work within residential premises, even through walls. In this case, Wi-Fi can be used to work with network functions such as Internet radio or DLNA(see above). Moreover, this option is more convenient than a wired LAN due to the absence of actual wires. In addition, support for this technology is a prerequisite for using AirPlay and Chromecast functions (see above); and in some devices, Wi-Fi even allows you to connect smartphones, tablets and other gadgets as remote controls.

One of the most modern and fastest standards of this wireless communication technology is Wi-Fi 5. The 802.11ac version uses the 5 GHz band (less congested and more noise-resistant than 2.4 GHz), providing speeds of up to 1.69 Gbps per antenna and up to 6.77 Gbps with multiple antennas.

— Bluetooth. Direct wireless communication technology between various devices. One of the most popular ways to use Bluetooth in audio systems is to work with an audio signal, primarily broadcasting sound to wireless headphones or speakers; and some models also provide the ability to connect a smartphone, tablet or other device and use the audio system as an external Bluetooth speaker. However, it is worth considering that initially Bluetooth is noticeably inferior to a wired communication in terms of sound quality; however, in our time, this disadvantage is often compensated by the use of one or another version of the aptX codec(see below).
In addition, other options for using Bluetooth may be provided - for example, exchanging files between the built-in memory and the same smartphone, or remote control via an application. They are not mandatory for modern audio systems, but with the development of technology they are becoming increasingly widespread.

In modern audio systems, the Bluetooth v 5 standard is most often used. Its important innovation is the expansion of the capabilities of the BLE (Bluetooth Low Energy) mode: if necessary, the device can increase the range by reducing the speed, or speed up transmission at the cost of reducing the range. In addition, a number of improvements have been introduced regarding simultaneous work with multiple connected devices.

- aptX support. The audio system supports aptX, a codec designed to improve the quality of sound transmitted via Bluetooth. Accordingly, this function automatically means the presence of a built-in Bluetooth module (see above). The need to use special technologies is due to the fact that in the original Bluetooth format the audio signal is very highly compressed, which significantly affects the final sound quality. The aptX technology is designed to correct the situation: according to the creators, it provides sound purity “comparable to Audio CD (16-bit/44.1kHz)” and almost as good as a wired communication. This is often enough even for comfortable listening to lossless formats, not to mention MP3 and other popular compressed formats. Of course, to use aptX, the signal source must also support it.

- aptX HD support. Audio system support for the aptX HD codec - an improved and updated version of the aptX described above. This version claims sound purity comparable to Hi-Res audio materials (24-bit/48kHz); this allows you to comfortably listen not only to MP3, but also to lossless formats and even uncompressed audio materials. On the other hand, aptX HD support is quite expensive, and its advantages over the original aptX only become noticeable on very high-quality audio materials, for which consumer audio systems are rarely used. Therefore, this function is not particularly widespread.

- A.A.C. A codec used primarily in Apple portable devices to improve sound transmitted via Bluetooth. In this sense, it is similar to aptX (see the corresponding paragraphs), but is 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 an average quality MP3 file. However, for listening to the same MP3s, this is quite enough; the difference becomes noticeable only on more advanced formats.

-LDAC. Sony's proprietary Bluetooth codec. It surpasses even aptX HD in terms of bandwidth and potential sound quality, providing performance at the Hi-Res level of 24-bit/96kHz audio; 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.

— Network streaming audio. The ability of the audio system to work with network streaming audio services such as Deezer, Spotify, Tidal, etc. Such services are designed to broadcast content (in this case, mainly music) over the Internet; in this case, the played files are not saved in the audio system, but are played directly from the corresponding resource on the World Wide Web. Nowadays, there are many streaming services that differ in the range of music and access conditions; The specific list of supported services should be clarified separately. However, in any case, the main advantages of online streaming include an extensive selection of content and almost instant access to the desired composition; Some services can also work like a radio, automatically selecting music according to the producer's preferences.

- Speakerphone. Possibility of using the device as a hands-free system for a mobile phone. In this mode, the audio system connects to the device, most often using Bluetooth (see above), and the voice of the subscriber on the other end of the line is output not to the phone, but to the speakers of the audio system. This is often more convenient than holding the phone to your ear; In addition, speakerphone is useful if several people need to participate in a conversation.

— NFC chip. NFC is a short-range wireless technology (about 10 cm). In audio systems, NFC is used primarily to facilitate communication via Wi-Fi or Bluetooth (see above). With this chip, you can simply bring an external NFC-compatible device to the audio system and confirm the communication - it's easier than manually adjusting settings.

— Omnidirectional sound. As the name implies, audio systems with this feature radiate sound evenly in all directions, covering a space of 360°. Thus, the device can be installed in the centre of the room and evenly “fill” it with sound, which will be clearly perceived at any point. On the other hand, an omnidirectional system usually sounds 1.0 (mono); the design may include various tricks to ensure surround sound, but these still in most cases do not reach full stereo.

— Voice assistant. Audio support for voice assistant. The most popular nowadays are such assistants:

• Google Assistant
• Apple Siri
• Amazon Alexa

However, other solutions are also possible. Anyway, it is worth noting that this is not about the function of the audio system itself, but about compatibility with smartphones, tablets and other gadgets that have their own voice assistants. Thus, to use the voice assistant, you will have to connect the audio system to an external device. On the other hand, the capabilities of such assistants are usually more extensive than those of built-in voice control systems(see below); advanced features are often supported, such as natural speech recognition with complex queries (“Play the last album of the band … that I listened to”), weather fore...cast, sports scores, etc. Of course, the specific set of supported commands and languages \u200b\u200bcan be different — depending on the voice assistant and its version.

— Voice control. A feature that is virtually mandatory for smart speakers (see "Intended Use") and hardly found in other types of audio systems. As the name implies, this control allows you to control the device using voice commands. It differs from the voice assistant (see the relevant paragraph) in that in this case we are talking about the simplest commands related to the main functionality of the audio system — for example, "Stop", "Continue", "Next track", etc. It is worth having in mind that voice control is almost guaranteed to support English, but the ability to recognize other languages should be specified separately.

— Smartphone control. The ability to control the audio system from a smartphone, tablet or other gadget with a special application installed on it. Usually, the connection is made via Wi-Fi (see "Interfaces"). The convenience of this function lies not only in the fact that you can control the system from a distance — the application is often more convenient and provides more options than the controls on the radio itself.

— Multiroom support. Device support for Multiroom technology. This technology allows you to create a single wireless network in the house from several speakers located in different rooms, and simultaneously play music in all these rooms. The specific features of such networks in different models may be different, they should be specified separately. So, some devices use a Bluetooth connection, others use Wi-Fi (directly or via a local network). In some cases, the control speaker broadcasts sound to all the others, and the same music plays throughout the house, in others, the speakers are “equal”, and different tracks can be turned on simultaneously in different rooms. Some audio systems require an external sound source (smartphone, tablet, etc.), others are capable of playing the role of a player themselves, including for streaming Internet services.

— 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.

— Karaoke. A popular entertainment that allows users to sing their favorite songs to the backing track (musical accompaniment with the original vocals cut out) — in such a way that the vocals superimposed on the backing track are played through the acoustics of the audio system. This feature requires at least one microphone input.

— Karaoke Mix. An extended version of karaoke (see above), which provides various additional features — for example, performance evaluation in points, singing competitions, etc. Usually, it allows you to connect two microphones already.

— Internet radio. Ability to listen to Internet radio stations on the audio system. In general, such broadcasting is similar to conventional broadcasting, however, it is carried out not through the radio, but through the World Wide Web, which provides some additional features. So, Internet broadcasting has no restrictions on the range and ranges, allows you to listen to programs from any country and in any language; and the list of broadcasters is extremely extensive, among them there are both traditional radio stations duplicating their programs on the Internet, and specific, purely network projects. The presence of this function assumes support for at least one network interface — Wi-Fi or LAN (see "Interfaces").

— Recording to a USB drive. The ability of the audio system to record to an external USB device — for example, a USB flash drive. In this way, you can record your favorite radio programs from a conventional tuner or Internet station (see above), copy music from optical discs, etc.; Specific USB recording capabilities vary by audio system model.

— Clock. Ordinary clock — a device for displaying time, most often in the form of numbers on the display. Sometimes these hours are the most convenient. In addition, this function is necessary for some other features — primarily the alarm clock (see below).

— Alarm. A classic alarm clock that sounds at a set time. It can be useful not only for wake-up calls, but also in other cases when you need to warn the user about the arrival of a certain time. A feature of this function in audio systems is that the inclusion of a specific radio station or musical composition can be used as a signal.

— Shutdown timer. A feature that allows the audio system to turn off automatically after a user-defined time. Thanks to the timer, you can, for example, turn on relaxing music to fall asleep and fall asleep peacefully — the audio system will turn off on its own.

— Nightlight. The presence in the audio system of its own built-in lamp of low power, which allows it to be used as a night lamp. A night light can be useful for both young children and adults who are uncomfortable falling asleep in complete darkness; in addition, it can come in handy in situations where you have to get up in the middle of the night or early in the morning, before sunrise — at least with the light from the nightlight, it's easier to get to the main switch.

— RCA. The RCA interface uses coaxial cables with characteristic "tulip" plugs and corresponding connectors. It can be used to transfer different types of data, however, in this case, it means connecting the audio signal from the preamplifier in analogue format, one channel of audio per connector. RCA is widely used in modern audio technology, but its resistance to interference is very limited.

— Mini-Jack(3.5 mm). Standard connector for most modern portable audio equipment. In audio systems, it is mainly used to connect such equipment — primarily pocket media players. It uses analogue signal transmission, while the resistance to interference, like RCA, is not high, and the quality may even be lower due to the fact that both channels of stereo sound are transmitted over the same cable.

— Coaxial S / P-DIF. An electrical version of the S / P-DIF standard, using a coaxial cable with a “tulip” connector for signal transmission. Do not confuse this interface with the analogue RCA described above — despite the identity of the connectors, these standards are fundamentally different: "coaxial" works in digital format and even multi-channel audio can be transmitted over a single cable. Compared to optical S/P-DIF, this interface is less resistant to interference, but more reliable because electrical cables are not as delicate.

— Optical. One of the va...rieties of the S / P-DIF standard is, along with the coaxial one described above. In this case, the signal is transmitted via a TOSLINK fibre optic cable. The main advantage of this interface is its complete insensitivity to electrical interference, while its capabilities are sufficient even to work with multi-channel audio. Among the shortcomings, it is worth noting the high price of connecting cables, as well as the need for careful handling of them.

— Under the microphone. Input for connecting a microphone to an audio system; can use different types of connectors (3.5 mm mini-Jack, 6.35 mm Jack, etc.). This function is mandatory for models with karaoke (see "Advanced"), but can be used for other purposes.

— Instrumental. Connectors used to connect musical instruments (acoustic or bass guitars, keyboards, etc.). Most often they are made in the form of 6.35 mm Jack format sockets. The audio signal from pickups has its own specific characteristics, so the instrument input typically features a higher input level and special impedance matching to ensure optimal sound quality.

The ability to use the audio system to charge devices connected to it – pocket audio players, mobile phones, etc. For this usually a USB port is used (microUSB or USB-C in modern models); some models are able to play music from an external gadget right in the process of charging.