What Are the Key Factors in My Audio Source?

When you’re building your audio setup, there is, perhaps, no piece more important than the source. Your source includes both the physical device that you’re using to playback music (a phone, laptop, or dedicated player) and the audio itself – whether it’s a digital audio file or a CD or even a record.

In a digital headphone setup, your source connects to a DAC (Digital to Analog Converter), an Amp, and finally your headphones. Today we’re going to talk about the source.

hi fi signal chain

The Device

In most cases, the source is a digital device like a laptop or phone. You can also use a standalone digital player. The source will determine a number of things, like “do I need a separate DAC or is the DAC built into my device good enough?” or “do I need a separate headphone amp?” With a high fidelity audio player, the answer to both of those questions might be “no.” With a laptop or phone, the answer to both is typically “yes.” Once you settle on the device you’re using, you’ll need to figure out how you’re going to play the actual audio off that device.

The Audio

You could spend $10,000 on a beautiful DAC, amp, and headphones setup, but that can’t fix the fact that the YouTube video you’re watching is highly compressed, low resolution audio. The same goes for those MP3s of your favorite band that you got off Limewire back in 2005. So let’s talk about the key factors in digital audio.

Understanding Digital Audio

Any sound creates a “wave” that we can hear. Often we visualize this as a “waveform”:

audio waveform

To create a digital audio file, the original waveform is chopped up and each part of the original wave is stored as a series of “bits” – 1s and 0s. Since sound waves create intricate curves and not flat or straight lines, you need a lot of bits to preserve the exact shape of the original wave to reproduce the original sound.

If you’re familiar with HD video technology, you’ll start to recognize some of the terms and principles from that world that also apply to digital audio. With video, the goal is to have a high enough resolution, deep enough colors, and a high enough frame rate that the human eye can’t tell the difference between the pictures on a screen and reality. The ultimate goal of high resolution audio (and high end sources, DACs, amps, etc.) is to recreate the experience of listening to live music.

Here are some of the key terms used in digital audio:

  • Sample rate: Measured in kHz, this is the number of times per second that a sample is taken of the audio. A higher number is going to be a more accurate recording. CD Audio is 44.1kHz.
  • Bit depth: Measured in bits, this is the number of data points used for each sample. CD Audio is 16 bits per channel (stereo).
  • Bitrate: Measured in kilobits per second (kbps), this is the total amount of memory that is allocated for each second of audio. The bitrate is derived from the sample rate and bit depth. So for CD Audio, you take 44,100Hz and multiply it by 16 bits and then by 2 channels (for stereo) and end up with 1,411kpbs. Higher bitrate means a bigger file, but a more accurate reproduction of the original audio.
  • Format: CD Audio, MP3, AAC, FLAC, and AIFF, among others. The format of the audio is a little bit more nuanced. Typically this will tell you whether or not a file is “compressed”  – which means that an algorithm has been to try to make the audio file smaller – and what kind of compression was used. Note: while you often can’t see the format of music being played over a streaming service, many popular services, like Spotify and Apple Music use compressed audio.

  • Choosing a Format for Listening

    Nowadays, most people listening to music are using a streaming service. While streaming music is typically delivered in a compressed, lossy format, there are services which provide high resolution options. Some services, like Qobuz provide high resolution streaming and downloads for all customers, while others like Tidal provide a high definition tier for a higher monthly fee.

    astell and kern player

    If you’re an old curmudgeon like me, and you want to own the music yourself, you’ll need to figure out what formats you prefer when you purchase music or rip a CD. Most common digital audio formats try to strike a balance between preserving the original sound, while also not making a huge file. Popular formats, like ACC and MP3 are compressed and “lossy,” which means that when the file was created from the original audio, some aspects of the original performance – typically some highs, lows, and dynamic range were lost.

    WAV is the grandaddy of digital audio formats – much older than MP3 or AAC – and the basis for CD audio. Now, for those outside of the Hi-Fi, audiophile world, “CD quality” typically means “the absolute best possible sound quality,” but that’s not always the case. AIFF, FLAC, and ALAC can all deliver music at true “hi-res” – better than CD quality – and there are also formats like DSD and MQA which were designed from the ground up to deliver audio at above CD quality. The trade off is that higher quality formats require more hard disk space or streaming bandwidth.

    Choosing an App

    One problem with using a more exotic high end audio format is that it might not be compatible with every music app out there. For PC/Windows, you have a number of free and premium options like Hysolid or Audirvana. For Apple products, VOX provides a free app which plays most hi-res formats on MacOS and iOS. For Android, you could use the free Onkyo Music Player, or any number of paid apps.

    The Bottom Line

    Whatever kind of music you listen to, and whatever type of Hi-Fi system you decide to build, it starts with the music itself. Getting the most out of your headphones might mean repurchasing some old MP3s on a higher quality format or switching to a streaming service that provides higher quality streams. Nobody said that the pursuit of the best listening experience was going to be easy – or cheap!

    CDs remain the standard for high quality audio, but maybe you want to push the upper end of what the human ear can perceive and explore high resolution audio. However you decide to do it, listening to high fidelity music starts with having a high fidelity source.