Comparison Denon HEOS Link vs Onkyo R-N855

— Receiver. The key feature of the receivers, which distinguishes them from the players (see the relevant paragraph), is the presence of a built-in power amplifier that allows you to connect passive acoustics to the device. The design may provide other connection options — preamplifier output, digital audio jacks, etc.; moreover, the set of outputs in receivers is often more extensive than in the players. However, the main feature is precisely the compatibility with passive acoustics.

— Player. Devices for playing audio from various sources — from an external device that broadcasts an audio signal, from a USB drive, from files on a built-in storage device, etc. The only exception in this regard is content from local networks and the Internet: devices with such capabilities are usually referred to as a separate category — network players(see below). The fundamental difference between the players and the receivers described above is the absence of a power amplifier. Thus, passive acoustics can only be connected to such devices through additional equipment.

— Network player. A variation of the players described above, capable of playing audio from network resources — streaming services (see below), computers and servers on the local network, etc. The specific set of network functions may be different, but they are necessarily available in one form or another. Also, many of these devices a...re capable of working with non-network sources, such as external audio devices or flash drives; however, such functionality may not exist. All such nuances in each case should be clarified separately.

The range of audio frequencies that the audio receiver can handle. The wider this range, the more complete the overall picture of the sound, the less likely it is that too high or low frequencies will be “cut off” by the output amplifier. However, note that the range of sound audible to a person is on average from 16 Hz to 20 kHz; There are some deviations from this norm, but they are small. At the same time, modern Hi-Fi and Hi-End technology can have a much wider range — most often it is a kind of "side effect" of high-end circuits. Some manufacturers may use this property for promotional purposes, but it does not carry practical value in itself.

Note that even within the audible range it does not always make sense to chase the maximum coverage. It is worth, for example, to take into account that the actually audible sound cannot be better than the speakers are capable of giving out; therefore, for a speaker system with a lower threshold of, say, 70 Hz, there is no need to specifically look for a receiver with this figure of 16 Hz. Also, do not forget that a wide frequency range in itself does not absolutely guarantee high sound quality — it is associated with a huge number of other factors.

The nominal sound power output by the audio receiver per channel when a load with a dynamic resistance (impedance) of 4 ohms is connected to it. It is customary to specify this parameter when the receiver is operating in two-channel mode (stereo); when using only one channel, the power may be slightly higher, but this mode cannot be called standard.

Rated power is the highest average (rms) output signal power at which the receiver is able to work for a long time without failures or malfunctions. The average power is taken because the audio signal is, by definition, unstable, and individual jumps in its level can significantly exceed the average value. However, the key parameter is still the rated (average) power. It determines two points — the overall volume of the sound and compatibility with one or another passive acoustics. The higher the power of the receiver, the louder the sound it can provide; at the same time, this power should not exceed the rated power of the speakers — otherwise, overloads and even damage to the equipment are possible.

According to the laws of electrodynamics, with a different load impedance, the output power of the amplifier will also be different. In modern speakers, values of 8, 6, 4 and 2 ohms are standard; the latter option, however, is rare, therefore, in audio receivers, the power for it, usually, is not indicated at all. As for specific power indicators at a 4-ohm load, values up to 100 W...are considered relatively small for modern receivers, more than 100 W — respectively, high.

The lowest speaker impedance that the audio receiver can handle normally.

The nominal impedance of the speakers, also referred to as the term "impedance", is one of the key parameters in the selection of audio system components: for normal operation, it is necessary that the speaker impedance match the characteristics of the amplifier. If the speaker impedance is greater, the sound volume will decrease significantly, if it is less, distortion will appear in it, and in the worst case, even overloads and breakdowns are possible. Therefore, in the characteristics of receivers, it is usually the minimum resistance that is indicated — after all, connecting a load of too low impedance is fraught with more serious consequences than too high.

Signal-to-noise ratio when operating the audio receiver through the RCA line input (see below).

Any signal-to-noise ratio describes the ratio of the level of pure sound produced by the device to the level of extraneous noise that occurs during its operation. This parameter is the main indicator of the overall sound quality — and very clear, because. its measurement takes into account almost all the noise that affects the sound in normal operating conditions. A level of up to 90 dB in modern receivers can be considered acceptable, 90 – 100 dB is not bad, and for advanced audiophile-class devices, a signal-to-noise ratio of 100 dB or more is considered mandatory.

The signal-to-noise ratio when the audio receiver is connected to the Phono input. This input is for connecting turntables; see "Inputs" for more details. The value of this parameter is described in detail in the "Signal-to-noise ratio (RCA)" section.

Audio file formats that the receiver is capable of working with. Among those, there may be lossy compressed (MP3, WMA, etc.), lossless compressed Lossless(FLAC, APE, etc.) and Uncompressed uncompressed formats (DSD, DXD, etc.).

In general, compression is used to reduce the volume of audio files. Lossy compression (the most common option) cuts off some of the audio frequencies (mainly those that are poorly perceived by the ear), making such files take up the least amount of space. Lossless compression preserves all original frequencies; this format is preferred by many lovers of high-quality sound, however, such files take up a lot of space, and the difference between normal compression and lossless compression becomes clearly noticeable only on high-quality equipment. Uncompressed formats, in turn, are intended primarily for professional audio work; their full reproduction requires Hi-End audio equipment, and the volumes of such materials are very large. However, these standards are quite popular among sophisticated audiophiles.

Separately, it is worth touching on the uncompressed DSD format. This standard and its direct derivatives DSF and DFF use coding using the so-called pulse density modulation. It is considered more advanced than traditional pulse-frequency modulation, and allows you to achieve more accurate sound, a higher signal-to-noise ratio...and less interference with a relatively simple element base.

A set of streaming services supported by the receiver.

Streaming (streaming) services are designed to broadcast content (in this case, mainly music) over the Internet. With such a broadcast, audio files are not saved on the receiver, but are played directly from the corresponding resource on the Internet; Nowadays, there are many such resources, varying in the range of music and access conditions. In any case, the main advantages of online streaming include a wide 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. Key resources include Spotify, TIDAL, Qobuz, Amazon Music.

— Airplay. A technology for transmitting multimedia data over a wireless connection ( Wi-Fi). Developed by Apple, it is intended mainly for broadcasting content from various Apple technology (primarily portable gadgets) to compatible external devices. Allows you to transfer audio files (in the audio streaming mode, see "Tuner and Playback" for details), as well as images, text data and even video. The presence of AirPlay in the audio receiver will allow you to connect Apple devices with support for this technology to it — for direct playback.

— Airplay 2. The second version of the AirPlay technology described above, released in 2018. One of the main innovations introduced in this update is multi-room support, the ability to simultaneously stream multiple separate audio signals to different compatible devices installed in different locations. Thus, for example, you can turn on the acoustics in the living room for training music from the iPhone, in the kitchen — a relaxing melody from the iPod, etc. In addition, AirPlay 2 received a number of other improvements — better buffering, the ability to stream to stereo speakers, as well as support for voice control via Siri.

— Chromecast. The original name is Google Cast. A technology for broadcasting content to external devices developed by Google. Allows you to transmit an au...dio signal from a PC or mobile device to the receiver, broadcasting is standardly carried out via Wi-Fi, while the receiver and signal source must be in the same Wi-Fi network (Chromecast media players are an exception). Chromecast technology supports two modes — the actual broadcast through special applications (available for Windows, macOS, Android and iOS) and "mirroring" content opened in the Google Chrome browser. However, the second option for audio receivers is not relevant, given the specifics of their application.

— Wi-Fi. A wireless interface originally used to build computer networks, but more recently, it also supports a direct connection between devices. It can be used in audio receivers in different formats: for network functions (streaming audio, Internet radio, DLNA, etc.), for broadcasting content via AirPlay or Chromecast (see above), and for connecting a smartphone as a remote control. An alternative option for connecting to networks is a wired LAN interface (see below), but Wi-Fi is more convenient due to the lack of wires and the ability to work through obstacles, including walls. In addition, the mentioned AirPlay and Chromecast work as standard through a wireless channel.

— LAN. Connector for wired connection to computer networks — "LAN" and/or the Internet. By itself, such a connection is less convenient than Wi-Fi (see above) due to the need to pull wires, but LAN support is somewhat cheaper, and the connection is faster and more reliable (especially when Wi-Fi channels are heavily loaded).

— Bluetooth. The technology of direct wireless communication between different devices at a distance of several metres. It can be used for a variety of purposes, but the main use of Bluetooth in audio receivers is to transmit an audio signal. At the same time, depending on the model, the sound can be transmitted both to the receiver (from a smartphone, tablet, etc.), and from the receiver to wireless speakers or Bluetooth headphones. It is believed that wireless transmission degrades sound quality, but this point is corrected in many devices using various advanced technologies such as aptX. Other uses for Bluetooth include remote control from an external gadget and file sharing between that gadget and the audio receiver's built-in memory.

— NFC chip. NFC technology is used for wireless communication over short distances (up to 10 cm). Potentially, it has many applications, but in audio receivers it is most often used as an auxiliary, to simplify the connection via Wi-Fi or Bluetooth. If there is NFC in a smartphone or other gadget, it is enough to bring it to the NFC chip of the receiver — and the devices will automatically “recognize” each other; then, depending on the settings, they will connect either automatically or after confirmation from the user. In addition, additional "chips" may be provided — for example, if music was playing on the smartphone at that moment, it will start broadcasting it to the receiver.

— DLNA. A technology used to connect various electronic devices into a single digital network with the ability to directly exchange content. Devices for which support for this standard is claimed are able to effectively interact regardless of the manufacturer. An audio receiver with DLNA is capable, for example, of playing music directly from a computer hard drive in the next room or from a smartphone in the user's hands. Connection to the Network can be carried out both wired (LAN) and wireless (Wi-Fi) way.

— USB A. The classic USB connector, familiar to most users from computers and laptops. In audio receivers, it is mainly used as an input for direct playback of music from flash drives and other drives, sometimes also for updating firmware and exchanging files between an external drive and built-in memory. Other application formats are also possible: for example, some models have a Type A output for transmitting a digital signal to an external DAC.

— USB B. This type of USB connector has an almost square shape, noticeably different from the popular USB A. The most common way to use it is to connect it to a computer as a peripheral device to control the audio receiver from a PC. However, there are other options — in particular, the use of this connector as an input for a digital audio signal.

— Card reader. A device for reading memory cards — most often various types of SD, although it's ok to clarify the specific types of compatible cards separately, as well as the possibilities for working with them. In general, this function is similar to USB Type A (see "Inputs"). Most often it is used for direct playback from memory cards, but other uses are possible — for example, copying music from a laptop to the receiver's built-in storage via a memory card.

— Internet radio. The ability to "receive" Internet radio stations using the receiver. Such transmissions are similar to conventional radio broadcasting, but are carried out not on the air, but through the World Wide Web; such broadcasting is carried out by many large radio stations, and there are also many specialized network channels. One of the key advantages of Internet radio is the lack of range restrictions, which allows you to listen to broadcasts from almost anywhere in the world and provides a wide range of choices. And for additional convenience, tools for searching and sorting Internet stations (by genres, languages, popularity, etc.) can be provided.