An affordable AV receiver is always a good option to consider, so Pioneer VSX-LX102 vs Onkyo TX-8140 comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Pioneer VSX-LX102 has 7.2 versus 2.0 for Onkyo TX-8140. Regarding power, then VSX-LX102 has such a W/Ohm ratio - 80/8, 170/6 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, AK4438 384 KHz/32-bit for VSX-LX102 and AK4458 384 KHz/32-bit for the TX-8140. Only the VSX-LX102 supports Bi-amping feature. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Rivals from our review have Bluetooth support. Spotify can be used on each receiver. The VSX-LX102 can work with the audio stream from Deezer, TIDAL, Pandora, TuneIn Radio, and the TX-8140 can receive a content from SiriusXM. Only the VSX-LX102 provides HDMI signal transmission in standby mode. The VSX-LX102 can scale the input HDMI signal, unlike the TX-8140. Dolby Vision technology found support only on the VSX-LX102. Only the VSX-LX102 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 VSX-LX102. These compared receivers have a built-in phono stage for connecting a vinyl player. A voice control is not available. An ECO mode is only available for the VSX-LX102. Both VSX-LX102 and TX-8140 can be configured using the Setup assistant.
Only the VSX-LX102 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the VSX-LX102.