Chapter 1: Understanding Hi-Res Audio

In my ongoing quest for the ultimate audio setup, I've come to appreciate the beauty of simplicity. There's something incredibly straightforward about simply donning a pair of headphones—whether wired or wireless—connecting to a streaming service, and immersing myself in my favorite tracks.

If you're someone who values the quality of your music experience, this article may resonate with you. Conversely, if you're satisfied with your current setup and prefer to focus on other interests, feel free to enjoy your music as is.

For those who, like me, have a penchant for fine-tuning and enhancing audio quality, particularly through Hi-Res audio, this guide is designed for you.

The term "Hi-Res" (High Resolution) audio is often mentioned, but what does it really mean? Is it essential? How can one access it? Can you differentiate between standard and Hi-Res audio? The answers vary based on individual preferences. If you’re intent on achieving the best possible sound quality, regardless of cost, then Hi-Res is the way to go. However, if you find comfort in listening to music via Bluetooth with standard earbuds, then Hi-Res might not be necessary for you. It's worth noting that while you’re enjoying CD-quality music, there exists a superior option that allows you to experience the nuances intended by artists and sound engineers.

Much of what you encounter regarding Hi-Res audio often comes from marketing campaigns. Sometimes the most critical information is what remains unsaid. Marketers aim to sell their products, but whether they genuinely assist in making informed choices is debatable.

The concept of Hi-Res audio is somewhat nebulous, lacking a universally accepted definition. Different vendors may categorize Hi-Res audio differently, and there are various tiers within that classification. At its core, Hi-Res audio refers to any music that surpasses CD quality.

Defining Hi-Res Music

CDs typically deliver audio at a standard of 16-bit and 44.1 kHz. Any audio that qualifies as Hi-Res must be at least 24-bit, with some arguing that Hi-Res begins at 48 kHz. According to the Japanese Audio Society, Hi-Res starts at 96 kHz, extending up to 192 kHz. Generally, 24-bit at 48 kHz is recognized as the minimal threshold for Hi-Res audio.

To convert analog music into a digital format, it is sampled and stored. This process involves two key factors: Sampling Rate, which is measured in kilohertz (kHz), and Bit Depth, expressed in bits.

#### Sampling Rate and Bit Depth

The Sampling Rate indicates how frequently the analog audio is sampled during its digital conversion. It affects the clarity and detail of the recorded music. For instance, CD quality audio is sampled at 44.1 kHz, meaning it captures sound 44,100 times per second. For minimal Hi-Res quality, the sampling rate is at least 48 kHz.

Bit Depth refers to how much data each sample contains, essentially measuring the quality and range of the audio. This metric is crucial for reducing noise and interference, allowing for a more accurate representation of sound dynamics.

Recording Options:

• Vinyl Records: This applies solely to analog formats; bits pertain to digital conversion.
• 16 Bit: Standard for most CDs and streaming.
• 24 Bit: Common in Hi-Res audio and some DVDs.
• 32 Bit: Rarely used but available in some Hi-Res formats.

What Is a Bit?

A bit, short for 'binary digit,' is a fundamental unit of computer data. It represents the simplest form of data, either a 0 or a 1. In terms of music files, each bit contributes to the overall sound quality.

In practical terms:

• 1 bit can represent 2 combinations (0 or 1).
• 16 bits can represent 65,536 combinations.
• 24 bits can represent over 16 million combinations, yielding a deeper audio experience.

For listeners, the distinction between 24-bit and 16-bit may not always be evident. A well-produced 16-bit recording can outperform a poorly executed 24-bit version. The 24-bit format is often used for "Master" recordings.

Another critical term is Bit Rate, which measures audio quality based on the combination of Bits and Sampling Rate, expressed in kilobits per second (kbps). Early digital music started at 64 kbps, with higher quality reaching 320 kbps in MP3 formats, while CD audio operates at 1411 kbps. In comparison, Hi-Res audio can reach up to 9216 kbps.

The Role of Equipment in Hi-Res Music

The inspiration for this exploration arose from a discussion with my brother about his home audio setup, which recently failed. His traditional audio system, primarily for TV viewing, consisted of a stereo receiver paired with wired speakers.

He typically streamed music via Bluetooth through his iPhone, using the free version of Pandora and Sirius. I recommended that he consider a SONOS system for better sound quality.

However, I pointed out that relying on Bluetooth and free streaming services compromised his overall audio experience. While he was content with Pandora, I emphasized that investing in better equipment wouldn’t be worthwhile if he continued to use low-quality streaming.

My aim in writing this article is to delve deeper into Hi-Res audio and share my findings with him.

Why Choose Hi-Res Music?

The primary goal of Hi-Res audio is to faithfully reproduce every sound captured in the studio.

Three key factors influence sound reproduction today: the recording itself, the streaming service used, and the listening device.

While CD music provides a broad spectrum of audible sounds, anything beyond 44.1 kHz and 16 bits enhances the fidelity of studio recordings. But why sample above human hearing limits?

#### Human Hearing and Equipment

The human ear can generally detect frequencies ranging from 20 Hz to 20 kHz, with most audio falling between 80 Hz and 15 kHz. Sampling above 20 kHz serves three main purposes:

1. Enhancing lower frequency sound reproduction.
2. Reducing distortion through improved filtering.
3. Capturing the essence of the music, which may be felt even if not directly heard.

The Nyquist Theorem states that to accurately reproduce a sound, you must sample at twice the frequency you want to capture. Therefore, to capture sounds up to 20 kHz, you need to sample at a minimum of 40 kHz—hence the Hi-Res classification.

Consequently, Hi-Res headphones should have a frequency response of at least 40 kHz for optimal sound quality.

Lossy vs. Lossless Audio

The terms "lossy" and "lossless" refer to how audio files are compressed for storage and transport. Lossy formats sacrifice some quality for reduced file size, while lossless formats maintain audio integrity. All Hi-Res audio is lossless, but not all lossless audio qualifies as Hi-Res.

As we transitioned from vinyl to digital formats, managing file sizes became crucial. Hi-Res audio files are significantly larger than traditional CD files, necessitating various formats for efficient storage:

• WAV: The standard format for CDs, but uncompressed and large.
• FLAC: A popular lossless compression alternative to WAV.
• ALAC: Apple’s version of FLAC.
• MQA: A compressed Hi-Res format gaining traction for streaming.

Bluetooth Limitations

Currently, all Bluetooth audio is lossy, which means it doesn't deliver Hi-Res quality. For the best experience, it’s advisable to use wired headphones. Incorporating an external DAC can also enhance audio beyond 24-bit/48 kHz.

Many streaming services now offer Hi-Res content at reasonable prices, enhancing accessibility for audiophiles.

Conclusion: What Type of Listener Are You?

Are you someone who seeks decent sound without a significant investment? If so, Hi-Res audio may not be on your radar yet. For those willing to invest a little more for improved sound quality, subscribing to a Hi-Res service and using existing hardware can yield better results.

Alternatively, if you're an audiophile who enjoys the pursuit of the best sound, you probably already have the necessary equipment.

For a tangible comparison, listen to a non-Hi-Res version of Pink Floyd's "Dark Side of the Moon" and then experience it in Hi-Res. The differences will be clear, allowing you to make an informed decision about your audio preferences.

To truly enjoy Hi-Res audio, ensure you have a Hi-Res recording, playback device, and possibly a DAC.

Here is my simple setup: an iPad, a lightning to USB CameraKit Adapter, a DragonFly DAC, and Bose QC 35 headphones. While the Bose may not be Hi-Res capable, the sound quality still surpasses standard CD audio.