It’s strongly recommended to compare different receivers if you want to choose the best one: Onkyo TX-NR555 vs Onkyo TX-SR444.
The number of channels for receivers is different - 7.2 versus 7.1, respectively, for devices. In terms of power, there are differences, the TX-NR555 has such a ratio W/Ohm - 130/6, while the TX-SR444 has a power of 100/6. A common feature for devices is the same total harmonic distortion - 0.08%.
The manufacturer installed different DACs, the TX-NR555 received the model Hi-Grade 384 KHz/32-bit, but the TX-SR444 is equipped with TI Burr-Brown 192 KHz/24-bit. The Bi-amping function is implemented only in the Onkyo TX-NR555. Both Onkyo TX-NR555 and Onkyo TX-SR444 can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Each of the receivers has a Bluetooth connector. The TX-NR555 has access to the Spotify service.
Support for the HDR function can only boast of the TX-NR555. The quality of 4K/60Hz signal remains unchanged when transmitting from a source to a TV or projector via HDMI for both receivers. Signaling over HDMI in standby mode can provide the TX-NR555 and the TX-SR444. None of the devices can increase the resolution of the incoming video signal. Review participants do not have the Dolby Vision feature.
The number of HDMI inputs/outputs varies depending on the receiver, the TX-NR555 has 6/1, and the TX-SR444 has 4/1. HDMI Audio Return Channel is implemented in both devices. HDMI eARC is not supported by the TX-NR555 and the TX-SR444. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. TX-NR555 and TX-SR444 support the standard HDCP 2.2. In the presence of a built-in phono stage for connecting a vinyl player only at Onkyo TX-NR555.
Ability to create 2 Multi zones inherent in both AV receivers. Voice control of the basic functions of the receiver is not realized in both models. There is an ECO mode in TX-NR555. None of these units can be properly configured using the setup assistant.
A Dolby Atmos multichannel audio format is available both models. Only in the TX-NR555 realized a DTS:X surround technology.