PCM vs Passthrough

When we were discussing the PCM vs Bitstream settings in the LG TV, the PCM vs Passthrough technology topic came up when we arrived at more complex architectural landscapes, such as the ones we have in the home theater arrangements. This is related to the other discussion of PCM vs. Bitstream because, after all, this is related to how well these technologies handle multiple intertwined audio channels and conversion to digital sound.

Audio PCM vs Passthrough matters whenever the TV sits between a source and the device that reproduces the sound. It can affect surround formats, lip-sync and compatibility in a home theater or gaming setup; with the TV’s own speakers, the practical difference is usually smaller.

Passthrough is not inherently better-sounding than PCM. It tells the TV to forward a compatible digital audio signal with little or no processing so the soundbar or receiver can decode it. PCM means the audio has already been decoded into samples; it can be stereo or multichannel, depending on the source, connection and devices.

If audio is out of sync, PCM is worth trying because it changes where decoding occurs, but it is not a guaranteed cure. Also test Auto or Passthrough and use the TV or receiver’s lip-sync control where available.

To know if we have a better experience with PCM or Passthrough, we connect a video source and a receiver to the TV in the Enhanced Audio Return Channel (eARC) or in a regular return channel (ARC) port.

Then, you have to play with the different audio formats desired, such as Dolby Digital of course, and check if the TV device can “passthrough the audio” through the receiver with its functionality and synchronization in perfect shape. We have to check PCM and Passthrough as well.

Audio passthrough is a way for you to connect multiple devices to your TV and pass high-quality audio signals to a receiver, which helps keep your setup clean, and you can use the video features your TV supports like HDMI 2.1 and variable refresh rate (VRR) that your receiver might not.

Passthrough reduces the number of cables necessary for a surround-sound system and gaming, and it makes your audio setup overall cleaner and less complicated.

The ease of using Passthrough devices makes them the best bet for some users, although true audiophiles would probably choose differently since it doesn’t genuinely improve the sound quality.

Pass-Throughs can transmit audio signals from a high-HD source to a home theater system using an HDMI cable.

This feature is useful with set-top boxes, game consoles and disc players when the downstream sound system supports the original codec. PCM may be preferable when the source has already decoded the soundtrack or when passthrough causes compatibility or synchronization problems.

Do not choose solely by speaker count. A stereo PCM output may limit surround through some TV, ARC or optical paths, while HDMI eARC can carry uncompressed 5.1 or 7.1 PCM. A soundbar or receiver must support the format that reaches it.

For CDs and ordinary stereo sources, PCM is a natural choice. For Dolby Atmos or another encoded surround format, Auto or Passthrough is often the safer starting point. Some sources deliver Atmos through Dolby MAT, so Atmos does not always mean a conventional bitstream.

Passthrough

To have the best home theater experience, you will not only need a TV with great picture quality, but you’ll also need the best sound experience possible. Audio passthrough is an important feature if you want to use your TV in a home theater setup and you’re playing content with high-quality audio. Audio passthrough is a way for you to connect multiple devices to your TV and pass high-quality audio signals to a receiver, which helps keep your setup clean, and you can use video features your TV supports like HDMI 2.1 and variable refresh rate (VRR) that your receiver might not.

PCM

Linear PCM is uncompressed audio, but that does not make it automatically better than every bitstream. A lossless format such as Dolby TrueHD reconstructs the audio bit-for-bit; the practical question is which device decodes it and whether the complete format survives the connection.

Some televisions limit PCM on ARC or optical output to stereo, but that is a product and connection limitation, not a limit of PCM itself. HDMI eARC can carry uncompressed 5.1 and 7.1 PCM, and compatible products can accept multichannel PCM.

Optical also carries PCM, normally as two-channel LPCM; it is false that only HDMI can transmit PCM. Use HDMI eARC when you need multichannel PCM or high-bitrate immersive formats, and check the manuals for both ends of the connection.

When To Use PCM Then?

PCM is a good option when:

The source or TV has already decoded the audio and every device in the path supports the resulting channel layout.
You are using stereo, need maximum compatibility, or PCM solves a dropout or lip-sync issue.
You use HDMI eARC for multichannel PCM, or optical/coaxial for supported two-channel PCM.

PCM vs Passthrough