Demystifying PCM: How to Get the Most from PCM Soundbars

Hey friend! Have you heard the terms "PCM" or "PCM audio" thrown around and wondered what that‘s all about? As a home theater geek and audiophile, let me break it down for you and explain how to unlock the full potential of PCM sound with your soundbar.

PCM 101

First, what does PCM stand for? It‘s an acronym for Pulse Code Modulation, which is a method of encoding analog audio signals into uncompressed digital data.

Here‘s a quick rundown of how it works its magic:

• An analog audio waveform is sampled at regular intervals, typically 44,100 times per second for CD-quality audio
• Each "sample" is a measurement of the waveform‘s amplitude at that instant
• This amplitude is rounded off to the nearest value in a range of digital steps
• For CDs, it‘s 16 bit resolution – 65,536 possible values
• This process converts the smooth, continuous analog signal into a sequence of PCM digital data

The more samples per second (sample rate) and the more digital steps (bit depth), the higher the audio resolution, and the closer it gets to the original analog sound.

No fancy compression or encoding – just pure, lossless digitized audio. This uncompressed PCM data can then be transmitted or stored.

On playback, the digital samples are reconstructed by a DAC chip back into an analog signal that amplifies out of your speakers. Pretty neat!

Why PCM Rules for Soundbars

So why does this PCM format matter for soundbars?

Simple – it allows soundbars to receive pure uncompressed multi-channel audio from your TV for the best possible sound quality. We‘re talking the highest fidelity audio reproduction that captures every detail.

Many other digital surround sound formats like Dolby Digital or DTS use "lossy" audio compression to cram multi-channel audio into limited bandwidth. Info gets thrown out.

But with PCM, you avoid that compromise – no compromising on sound quality for the sake of efficient transmission. You hear the full audio just as it was recorded originally.

For critical listening, audiophiles almost always prefer the transparency of uncompressed PCM over compressed surround sound. No contest!

PCM vs Other Audio Formats

To highlight the difference, let‘s compare PCM to common compressed formats:

Format	Compressed?	Max Channels	Surround?	Typical Use
PCM	No	8	Yes	Blu-ray, Games, Streaming
Dolby Digital	Yes	5.1	Yes	DVDs, Streaming
DTS	Yes	5.1/7.1	Yes	Blu-ray, Streaming
Dolby Atmos	Yes	7.1.4	Yes	Blu-ray, Streaming

PCM

As you can see, uncompressed PCM can support up to 8 channels of discrete surround sound – even more than the 5.1 typical of Dolby Digital or DTS. And with no audio compression, you hear the full fidelity and dynamics of the original source.

Blu-ray discs and high-end game consoles often utilize multi-channel PCM for the best possible sound quality.

Downside – multi-channel PCM requires high bandwidth connections to deliver all that pristine audio data. More on that soon!

Dolby Digital

Dolby Digital, aka AC-3, was developed in the 90s to deliver 5.1 surround sound more efficiently, especially for the limited bandwidth of DVDs.

It analyzes the audio and discards imperceptible data. The result is compressed audio reduced down to 320 kbps while still retaining discrete 5.1 channels.

You get surround sound, but at a cost of some fidelity compared to uncompressed audio. It met the needs of DVDs, but audiophiles still preferred PCM whenever available.

DTS

DTS Coherent Acoustics is a similar compressed surround sound format that emerged as an alternative. DTS trades blows with Dolby Digital and supports higher channel counts like 7.1 on Blu-ray discs.

Like Dolby Digital, DTS discards less critical data to shrink down the audio for efficient 5.1 and 7.1 surround. Still quality loss compared to PCM.

Dolby Atmos

This is the new kid on the block, built for immersive surround sound by adding in overhead speakers. Dolby Atmos objects allow sounds to be precisely positioned and moved in 3D space.

Amazing, but Atmos still relies on lossy compression to pack all those objects and channels into an efficient audio stream around 1 Mbps.

So PCM still wins for 2 channel fidelity. But for the ultimate in surround immersion, Atmos can‘t be beat!

Connecting a PCM Soundbar

Alright, let‘s get into the nitty gritty of setting up your PCM-ready soundbar properly:

HDMI ARC/eARC

To enjoy uncompressed multi-channel PCM in all its glory, HDMI is by far the best connection option.

HDMI ARC (Audio Return Channel) allows TV audio to be sent "downstream" to a soundbar on the same cable you use for video. No separate optical audio cable needed!

Even better is HDMI eARC on latest TVs, with more bandwidth for high resolution PCM and object-based surround like Dolby Atmos.

When using HDMI, be sure to enable PCM or Bitstream output (not DTS Neo or other processing) on your playback devices. The soundbar will decode the formats.

According to Dolby, HDMI eARC can handle up to 5.1 compressed audio and 2 channel PCM uncompressed. For full 7.1 PCM, dual HDMI inputs are recommended.

Optical Digital Audio

If HDMI isn‘t an option, optical cables (using TOSLINK connections) allow you to extract digital audio from your TV.

But be aware – optical is limited to stereo PCM only! Optical cannot pass multi-channel surround PCM. DTS and Dolby Digital will be downmixed to stereo.

Still, two-channel PCM over optical can sound great. Enable PCM audio output on your devices and disable Dolby processing if possible.

Analog Audio

Last resort is analog audio cables from your TV‘s headphone jack. Analog converts the PCM back to continuous electrical signals.

This allows multi-channel PCM to pass, but is susceptible to interference and quality loss. Use analog only if digital options aren‘t available.

PCM Settings on Playback Devices

If you want to enjoy pristine multi-channel PCM from Blu-ray or games through your soundbar, you need the source device setup correctly:

Blu-ray Players

Look for settings like "HDMI Audio" or "Audio Output" and select PCM or Bitstream, NOT Dolby Digital conversion.

Many Sony Blu-ray players have options like "Direct" or "Mix" – choose Direct for unprocessed PCM.

Game Consoles

Again, enable PCM or Bitstream output. On Playstation 4/5, select Linear PCM and disable DTS Neo processing.

Switch Xbox Series X|S to Bitstream out. The console will decode Atmos into PCM for the soundbar.

Streaming Devices

Set audio output to PCM Stereo on devices like Roku, Fire TV, Apple TV 4K for the best quality. No surround PCM, but avoids Dolby transcoding.

TV Settings

Enable options like "Pass-through" or "Bitstream" for the TV audio output. Disable TV speaker audio processing like "Virtual Surround".

Cranking It Up to 11 with High-Res PCM Audio

Think PCM sounds amazing already? Well let me introduce you to the world of high-resolution PCM audio!

Remember how I explained PCM samples the analog audio waveforms 44,100 times per second for CD quality? Turns out we can sample way, way faster for even clearer sound.

High-res PCM cranks up the sample rate – from 96 kHz up to 192 kHz. Some ultra-high-end systems even play 352 kHz or 384 kHz PCM!

Higher resolution means more precision in digitizing the audio waveform. You hear improved details and spatial imaging. Cymbals shimmer, acoustic guitars pluck, vocals sparkle…ecstasy!

Don‘t just take my word for it. According to researchers at Japan‘s NHK Science & Technology Research Laboratories:

"High-resolution audio can reproduce the entire hearing range, giving better sound quality, even surpassing CDs and approaching analog sound quality."

Now, you‘ll need high-end equipment to enjoy PCM above 48 kHz sample rates. Look for AV receivers, portable players, headphones, and speakers with 192 kHz PCM support.

Sadly, many soundbars max out at 48 kHz over HDMI. But some premium models from Sony, Yamaha, and LG now accept 96 kHz or even 192 kHz PCM.

If you‘re really serious, you can even find high-res music recorded in pure PCM format up 192 kHz from sites like HDtracks. No compression whatsoever!

Demystified? How to Choose the Right Audio Format

That covers the essential facts about the PCM phenomenon. Let‘s wrap up with some tips on picking the best audio format for your needs:

💿 For pristine fidelity with music, Blu-rays, or games, always go PCM when available. You want uncompressed quality.

🎧 If you have basic stereo speakers, stereo PCM gets the job done nicely without surround processing.

🎚️ Compressed Dolby and DTS formats are great for efficient 5.1 and 7.1 surround on low bandwidth connections.

🌟 For truly immersive 3D audio, Dolby Atmos is amazing. But HDMI eARC required for soundbars.

👾 HDMI connections are king for lossless multi-channel PCM. Optical only supports 2 channel PCM.

🎸 For high resolution 96kHz+ audio, you need PCM-compatible premium equipment. Worth it for critical listening!

There you have it amigo! Let me know if you have any other questions. I‘m always happy to gab about geeky audio stuff. Now get out there and help your soundbar reach its full PCM potential!