Having had an opportunity to test Onkyo TX-SR343 vs Onkyo TX-NR545, I’d like to share my impression here to facilitate your choice of a new AV receiver.
The number of channels for receivers is different - 5.1 versus 7.2, respectively, for devices. In terms of power, the receivers have the same performance - 100/6. A common feature for devices is the same total harmonic distortion - 0.08%.
The manufacturer installed different DACs, the TX-SR343 received the model TI Burr-Brown 192 KHz/24-bit, but the TX-NR545 is equipped with Hi-Grade 384 KHz/32-bit. The Bi-amping function is implemented only in the Onkyo TX-NR545. The model TX-NR545 can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Each of the receivers has a Bluetooth connector. The TX-NR545 has access to the Spotify service.
Support for the HDR function can only boast of the TX-NR545. 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-SR343 and the TX-NR545. 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-SR343 has 4/1, and the TX-NR545 has 6/1. HDMI Audio Return Channel is implemented in both devices. HDMI eARC is not supported by the TX-SR343 and the TX-NR545. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. TX-SR343 and TX-NR545 support the standard HDCP 2.2. Unlike most receivers, our models do not have a built-in phono stage for connecting a vinyl player. Voice control of the basic functions of the receiver is not realized in both models. There is an ECO mode in neither AV receiver. The Onkyo TX-NR545 can be properly configured using the setup assistant.
A Dolby Atmos multichannel audio format is available only in the TX-NR545. A DTS:X surround technology is not supported by devices from our comparison.