Onkyo TX-NR818 has 7 channel amplifier and delivers 135 W (8 Ω, 20 Hz - 20 kHz, 2 channel driven) and also has a stable performance at 4 Ω load. This receiver even supports front wide channels which is found only in a very few high-end receivers these days.
The Receiver has 1080p passthrough and 4K upscaling up to 30p.
Onkyo TX-NR818 features Onkyo’s Wide Range Amp Technology (WRAT) circuit layout that prevents phase shifting by pushing the roll-off point higher than the listening-level frequency. Amplifying sound without phase shift creates an uncommonly well-focused and realistic audio image. If phase shift occurs and signal timing is not accurate, then neither is the resulting audio image.
3-Stage Inverted Darlington Circuitry
Onkyo TX-NR818 features 3-Stage Inverted Darlington Circuitry. Standard amplifiers employ a negative feedback (NFB) design that counters distortion by feeding back the opposite phase of the output signal into the input stage. Unfortunately, NFB is easily affected by inverse electromotive forces from the speakers, leading to an increase in circuit noise. Three-Stage Inverted Darlington Circuitry is a core Onkyo technology incorporating a low-NFB design that makes the sound more natural. Sensitive to oscillations, this circuitry requires very advanced control technology in order to be incorporated into the amplifier.
Onkyo TX-NR818 is THX™ certified which offers optimal performance, superior quality and seamless integration. THX works with partners from the ground up, so that certified products deliver professional quality audio-visual experiences right out of the box. They only certify the very best products with uncompromised quality, performance and consistency. They ensure that THX certified devices play well with lower performing devices and components. THX listening modes make the receiver to have one speaker set up for movies, music and games. They are tested for power output, bass management, signal-to-noise ratio and feature RE-EQ, timbre matching, boundary gain compensation and THX Loudness Plus. The current model has[y] Select™2 Plus class performance. This means that it is ideally suited for a room where the screen-to-seat viewing distance is approximately 3 to 4 meters, and the room size is approximately 56 cubic meters.
Advanced Music Optimizer
Compressed music enhancement in Onkyo TX-NR818 is done by Onkyo’s Advanced Music Optimizer. While MP3 or AAC files may sound fine through the headphones of your portable digital player, the limitations of these files can be exposed when played back through a quality home entertainment system. This is because a significant amount of high-frequency bit information is lost during the file-compression process. To counter this, Onkyo has designed the Advanced Music Optimizer to compensate for lost bit information and improve the quality of compressed audio signals. This results in a clearer and more expansive sound. Also included in this technology is a loudness correction feature that further improves the audio character of compressed files.
Onkyo TX-NR818 comes with Audyssey Dynamic EQ, Audyssey Dynamic Volume and Audyssey DSX.
Audyssey Dynamic EQ selects the best possible frequency response and surround volume levels moment-by-moment. This ensures that the bass response, tonal balance and surround impression remain constant despite changes in volume. This is the first technology that carefully combines information from incoming source levels with actual output sound levels in the room, a pre-requisite for delivering a dynamic volume solution.
Your Listening experience can be greatly diminished when there are significant shifts in volume between television programs, commercials and within the program material itself. When this happens you must constantly adjust the volume to maintain your desired listening level. Audyssey Dynamic Volume monitors the volume of program material moment-by-moment and automatically adjusts it, maintaining the desired listening level for all content while optimizing the dynamic range to preserve impact.
Audyssey DSX allows you to augment a standard five-channel home theater with either two Front Wide or two Front High speakers. The Wide channels create an expansive soundstage and bring out convincing directional effects. Alternatively, Height channels can add a vertical dimension to movie and game soundtracks.
Onkyo TX-NR818 comes with[y] Audyssey MultEQ XT32 room correction system and includes the calibration microphone.
Audyssey is an acoustic measurement technology which automatically restores the acoustic distortion caused by the acoustic behaviour of a room with only a push on a button. Audyssey equalization provides an clear, accurate, natural sound with voices and dialog that become focused and intelligible, restoring the musical balance. Musical instruments and sound effects become precisely localized and the surround soundstage is made seamless and enveloping.
Onkyo TX-NR818 can be connected to internet using ethernet cable or wirelessly[y] via Front USB (optional UWF-1 sold separately). It has 8 HDMI inputs and HDCP 2.2 copy protection. There is a phono input with built-in phono stage for connecting the cartridge output of the turntable directly to the Receiver. There are 9.2 channel analog pre-outs for external amplification.
Front panel has HDMI/MHL, USB, Composite Video, RCA Audio and Optical inputs.