An affordable AV receiver is always a good option to consider, so Denon AVR-X540BT vs Onkyo TX-8140 comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Denon AVR-X540BT has 5.2 versus 2.0 for Onkyo TX-8140. Regarding power, then AVR-X540BT has such a W/Ohm ratio - 70/8, 90/6 when TX-8140 has a power of 80/8, 110/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/24-bit for AVR-X540BT and AK4458 384 KHz/32-bit for the TX-8140. None of the models support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Only the Onkyo TX-8140 can connect to the Internet via WI-FI. Rivals from our review have Bluetooth support. Each of these units does not support Apple Music. Spotify can be used on each receiver. The AVR-X540BT can work with the audio stream from TIDAL, Pandora, and the TX-8140 can receive a content from SiriusXM.
Only the Denon AVR-X540BT has support for High dynamic range (HDR). Only the AVR-X540BT provides HDMI signal transmission in standby mode. Both competitors are not able to scale the HDMI signal. Dolby Vision technology found support only on the AVR-X540BT. Only the AVR-X540BT supports HDMI Audio Return Channel (ARC). Unfortunately, HDMI eARC is not available on monitored devices. Of the two receivers in our comparison, HDMI CEC is present in only the AVR-X540BT. The TX-8140 has a built-in phono stage for connecting a vinyl player. A voice control is not available. An ECO mode is only available for the AVR-X540BT. Both AVR-X540BT and TX-8140 can be configured using the Setup assistant.
None of the rivals equipped with Dolby Atmos multichannel audio decoder. The receivers do not support the surround sound technology DTS:X.