Many clients who visit Perfectionist Auto Sound & Security have heard the term hi-res, but they don’t know what it means when it comes to audio. Let’s look at what it is, and what high resolution audio means for your mobile entertainment system.
High Resolution Audio: The Physical
When you hear a sound, it is comprised of many different frequencies. When a studio engineer uses a microphone to capture these sounds, the output of the microphone is an analog waveform. Understanding how much detail we capture from that microphone is the first step to understanding audio resolution.
High Resolution Audio: Volume Resolution
When the engineer captures the signal from that microphone on a computer, some limits occur. The first is the number of different volume or voltage levels he can capture. Before hi-res audio, CD quality recordings had a resolution of 16 bits. That is 2 to the power of 16 or 65,536 different possible voltage levels he could capture as a digital signal. With hi-res audio, the limit has been increased to 24 bits or a possible 16,777,216 levels. That is 256 times more detail.
High Resolution Audio: Extended Response
If we look at the range of frequencies that conventional CDs could store, the upper limit was 22.05 kHz. While this is beyond our range of hearing, there are still limits to the detail of the high-frequency information stored. Hi-res audio has an upper-frequency limit of 96 kHz, although most car audio implementations will be limited to 48 kHz due to computer processing limitations. The extra frequency resolution increases the number of samples per second, and better captures the original analog signal. By way of an example, when you compare a standard CD quality sampling rate of 44.1 kHz to 96 kHz, we have more than twice as many samples per second to capture the original sound more accurately.
High Resolution Audio: The Benefit
While most of us can’t hear much beyond 15–16 kHz, the real audible benefit of listening to hi-res music is the effort that goes into capturing and mixing the original performance. Engineers use much higher-quality microphones and analog-to-digital conversion equipment. The amount of background noise each of these components adds to the mix is usually less than that of older equipment. The end result is music that is more detailed and transparent. Audiophiles will argue that the reproduction of high-frequency information above what we can hear can produce psychoacoustic effects that change our perception of the performance – we will leave that up to you to determine.
High Resolution Audio: The Medium
How do you get your hands on high-res music? Many websites are dedicated to selling hi-res versions of the music you like. You have the option of what file format you want to download in, and at what resolution. One of the most popular hi-res audio formats is FLAC (Free Lossless Audio Codec) files. These files employ file compression, rather than information removal (like MP3 and WMA), to reduce files sizes. Other formats include ALAC (Apple Lossless Audio Codec), WAV, AIFF and DSD. Here are some websites you can visit to purchase hi-res audio:
There are rumors that Apple is considering including hi-res audio files in the iTunes store shortly.
If you are in the Anchorage, Alaska area, we invite you to drop by Perfectionist Auto Sound & Security and audition your hi-res audio files on one of our displays. We have many different radios and multimedia systems that support the latest hi-res file formats. For more information about any of our products or services, please contact us here.