PCM vs Passthrough vs Auto | Audio Output Modes Comparison

When setting up your audio or home theater setup, you’re likely to encounter terms like PCM, passthrough, and auto. These are three common audio output formats that are often used in audio and video playback scenarios.

The right selection of an audio output format can significantly impact your audio experience, so understanding their differences and when to use each is crucial. In this blog post, we’ll delve into the PCM vs Passthrough vs Auto comparison in terms of their audio quality, compatibility, advantages, disadvantages, and more.

At the end of the article, you’ll have a clear understanding of each audio format, which will help you choose the best one based on your needs and preferences.

PCM vs Passthrough vs Auto – Comparison Table

FeaturePCM (Pulse Code Modulation)PassthroughAuto
DefinitionAn audio output format that converts analog audio signals to digital signals without any compression.An audio output mode that transmits the original audio from the source to the playback device, avoiding any conversion or processing.A setting in which an appropriate audio format is selected based on the input signal.
CompatibilityWidely supported audio format and is compatible with almost all audio devices.Requires compatible audio equipment, such as passthrough soundbars, AV receivers, and HDMI cables. Not all devices support passthrough.Compatibility is based on the input signal and what audio format your TV can recognize and process.
Audio QualityHigh-quality audio due to uncompressed audio signals.Highest possible audio quality due to advanced audio codecs.Audio quality depends on the input signal and which audio format is chosen on the TV.
Surround Sound SupportMost TVs support only 2-channel audio but can support up to 7.1-channel audio.Supports multi-channel audio formats for an immersive surround sound experience.Supports multiple audio formats, including surround sound, which depends on the input signal and capabilities of your TV.
Ease of UseNo configuration settings are required, as the PCM format is universally supported. Not best for surround sound setups.May require manual configuration and compatibility checks. Less user-friendly than PCM or auto modes, which handle settings automatically.Choose the best audio format automatically, simplifying the user experience. It’s better for surround sound if your TV supports advanced audio formats.
PCM vs Passthrough vs Auto Comparison Table


PCM, which stands for Pulse Code Modulation, is an uncompressed audio output format that represents the data as a series of discrete values. It converts analog data into digital signals that will be played through your audio system.

When you select PCM as your audio output mode, the source device decodes and processes the audio signal internally and sends it as a digital signal to your audio system. This means that with PCM, all audio decoding and processing occurs on the source device before transmission.

As PCM is an uncompressed audio format, no data loss occurs during the encoding process. Though it results in larger file sizes, the audio quality is excellent. Due to the highest quality audio, PCM is preferred for music production. PCM is typically transmitted through the HDMI port in a home theater system.

Advantages of PCM

  • Highest audio quality as no data loss occurs during the encoding process.
  • There is no compression artifact, as this is an uncompressed audio format.
  • preserved the original audio signal, which is important for archiving and broadcasting.
  • Can be used with a wide range of equipment as it is widely supported by audio devices and software.

Disadvantages of PCM

  • Limited bit depth
  • Large file size, which can be a disadvantage for applications where storage space is limited, such as mobile devices.
  • Not suitable for downloading or streaming as PCM requires too much bandwidth.

When to use PCM

  • PCM should be used when you want the highest possible audio quality.
  • When you want compatibility with a wide range of devices.
  • For standard audio playback in most situations.
  • For music production, i.e., during recording or mixing music, to preserve the original sound.
  • For mastering a music recording, archiving audio recordings, and broadcasting.
  • For designing sound effects for movies or video games to create realistic and immersive soundscapes.
  • For gaming

Ultimately, the best way to decide when to use PCM is to consider your requirements and specific needs. If you want high-quality sound, wide compatibility, and are not concerned about file size or bandwidth, then PCM is the best choice. On the other hand, if you’re concerned about bandwidth or file size, then you may want to consider a compressed format.


Audio passthrough is a feature that allows signals to pass from one device to another without any processing, conversion, or modification. This is mostly done by connecting the two devices through an HDMI cable.

Audio passthrough can help preserve the original sound quality as there is no processing involved by any device. So, you can use audio passthrough to transfer high-definition audio signals. HDMI cables can carry multiple audio formats, including DTS:X and Dolby Atoms, which can provide a more immersive surround sound experience.

Audio passthrough can help simplify your home theater setup. You can connect all of your devices to a soundbar or an AV receiver and then send video and audio signals to your TV using a single HDMI cable. In this way, you can reduce clutter and make your setup easier to manage.

Audio passthrough can improve the sound quality of your home theater, so make sure you choose devices for your home theater setup that support audio passthrough. Some devices that support audio passthrough include TVs, soundbars, AV receivers, streaming devices, Blu-ray players, and game consoles.

Advantages of Passthorugh

  • Improved sound quality.
  • Support for high-definition audio formats.
  • Simplified home theater setup.
  • Reduced latency, which is the delay between when an audio signal is produced and when it is heard.
  • Improved compatibility of your devices.
  • Audio passthrough can help save energy as there is no processing involved.
  • Bypassing processing, audio passthrough can help improve the reliability of your system.

Disadvantages of Passthrough

  • Requires compatible devices.
  • Can be more complex to set up.
  • Can be limited in functionality as it may not support all the features that are available on the source device.
  • Audio passthrough devices are often more expensive than devices that do not support this feature.

When to Use Passthorugh

You should use audio passthrough when you want to:

  • Get the best possible sound quality, as audio passthrough preserves the original sound quality.
  • Use high-definition audio formats, as HDMI cables can carry a variety of audio formats, including DTS:X and Dolby Atoms. These formats provide an immersive audio experience.
  • Simplify your home theater setup as this single HDMI sends signals to your TV. This reduces clutter and makes your home theater setup easier to manage.
  • Reduce latency (audio delay), which is especially important for gaming, where small delays can be noticeable.

If you are not sure whether or not you should use audio passthrough, it is always best to consult with a home theater expert. They can help you assess your needs and recommend the best solution for your system.

Auto Mode

Auto is an audio output mode in your device’s audio settings that automatically selects the best available audio format based on the source material and capabilities of both the audio input and output devices and then sends the audio signal to the output device.

Auto is the default setting on most devices, and it is a convenient choice for most users as the device handles the audio settings automatically. In some cases, the auto mode may not work properly.

For instance, if there are multiple output devices connected to your device, Auto may not be able to determine which is your default output device. In this case, you can manually select the audio output device.

To select the audio output device, go to the audio settings of your device, where you’ll see a list of available audio output devices. Choose the device that you want to use as the default output device.

Advantages of Auto

  • Automatic detection: the auto mode automatically detects the input and output devices and then chooses the right audio format accordingly.
  • Convenience is the main advantage for most users, as they don’t have to deal with manual format selection, which can be frustrating.
  • Auto mode is compatible with most audio devices.
  • Adaptability is also a feature of Auto, as it can seamlessly handle various audio formats and adjust settings accordingly.

Disadvantages of Auto

Here are some of the disadvantages of Auto audio output mode:

  • Potential for confusion as auto might not always select the optimal audio output format, which can cause compatibility issues or reduced audio quality.
  • It may not work properly if multiple audio devices are connected.

Overall, the auto audio output mode is a convenient way to ensure that the correct audio format is selected based on the audio content and devices. However, it is important to be aware of the potential disadvantages of this before using it.

When to Use Auto

You should use audio passthrough when you want:

  • A hassle-free audio experience.
  • In situations where you frequently switch between various audio content types.
  • You don’t want to dive into technical situations.
  • You want a balance between compatibility and quality.
  • When you are having problems with auto audio output mode.
  • When you’re switching between different audio output devices, such as headphones or speakers.

Auto is the most convenient and useful of all output modes. However, it is important to be aware of all the potential issues and the ideal situations for its usage before using it. Ultimately, the best way to use auto audio output mode is to experiment with it and see what works best for you.

Final Words

In conclusion, the choice between PCM vs Passthrough vs Auto depends on your audio devices and the type of content you listen to. While passthrough provides the best possible sound quality for compatible audio setups, Auto and PCM offer flexibility and ease of use.

I recommend you check your device’s manual and settings to make the most of your audio experience. Whether you’re a gamer, a cinephile, or a music enthusiast, understanding these audio formats will help you achieve the best sound quality for your audio setup.

Frequently Asked Questions (FAQs)

Is PCM better than passthrough?

Passthrough and PCM are both lossless audio formats, but they offer different advantages. Due to its bit-perfect nature, PCM preserves the original audio signal without impacting its quality. On the other hand, passthrough allows audio signals to be passed through untouched to the soundbar. When you have a high-quality soundbar that can decode and process the audio signal more accurately than your TV, this can be beneficial.

Should I use passthrough with a soundbar?

Passthrough should be used with high-end soundbars that can decode and process audio signals. As a result, you will receive the best sound quality possible. When your soundbar doesn’t have these capabilities, you should instead use PCM.

What does passthrough mean on the soundbar?

Passthrough refers to the fact that the soundbar will pass your audio signal directly to your TV without modifying it. If your TV is capable of decoding and processing audio signals better than your soundbar, this can be useful.

Is PCM still surround sound?

PCM can still be used for surround sound. The PCM format is bit-perfect, which means the original audio signal is preserved. Surround sound information is included in this, though it is not preferred.

Should I use HDMI passthrough?

HDMI passthrough is recommended if your soundbar supports it. By doing this, you will be able to get the best sound quality out of your soundbar.

What is Dolby passthrough?

Through Dolby passthrough, you can send audio from your TV to your soundbar in Dolby Digital or Dolby TrueHD formats. It is especially useful if you have a high-end soundbar that decodes and processes Dolby Digital and Dolby TrueHD audio.

Is PCM or auto better for the soundbar?

In order to get the best possible sound quality from your soundbar, you should use PCM. If you want a more convenient soundbar experience, auto is a better choice.

What is PCM audio vs auto?

Bit-perfect PCM audio preserves the original audio signal without any loss. With Auto, your TV will automatically pick the best audio format for your soundbar based on the content you are watching.

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