I loaded the box, configured the plate amp, and measured the result. A 24/96k plate amplifier with on-board DSP was used to drive the monitor. My first stab at the playback system involved a custom two-way studio monitor with a ribbon tweeter. I dropped my target resolution to 24/96k and proceeded. Loudspeaker technology is limited to about half that, to be charitable, and air absorption would wreak havoc on anything higher than 20 kHz, even at a few meters. It immediately became apparent that 96 kHz of analog bandwidth all the way to the listener is an impossibility. What better scenario than a room full of audio professionals, and three days of training on the fundamentals of digital audio? The idea was to configure a high resolution (24/192k) playback system that seminar attendees could use to compare digital resolutions. I decided to use the SAC Digital seminar for a resolution experiment. Digital resolution is something that you can self-assess, and I have created some resources that can help. The truth, in this case, is what is right for you. As with most things, you can forget going there to get to the truth. Theories and opinions abound on the Internet. At some point, “more” is not necessarily “better,” and in some cases it may be worse. We want our bandwidth to be wide enough, but not too wide. It’s entirely possible that these artifacts will be far higher in level than the harmonic content of the program material that you are trying to reproduce. Higher bandwidth systems may be able to pass the “nasties” that often exist above 20 kHz, such as artifacts from switch-mode power amplifiers and noise shaping circuits. Increasing the digital audio resolution beyond what is needed can strain playback and recording systems and force compromises that include lower channel counts, more storage space, a heavier processing load for your DSP, and greater required bandwidth for streaming. Just because something is possible doesn’t mean it is necessary. Most DSPs use a 48 kHz sample rate and 24 bit words (24/48k). It has been increased to a more logical 48 kHz rate, yielding a bit more high frequency extension. Those who deal with professional sound systems rarely encounter 44.1 kHz as a sample rate option. Technology broke through these limits long ago, and today the most common bit depth is 24 bits, and sample rates of 192 kHz and beyond are possible (24/192k). This is often described as simply “16/44.1k.” This translates into an analog dynamic range of approximately 96 dB, and an analog bandwidth of approximately 22 kHz. “CD quality” audio resolution uses a 16 bit word for each sample. The dashed red lines indicate the practical limits of current analog performance. The green box highlights the approximate limits of human perception. Is anything gained by making it better than it needs to be?įigure 1 – This graphic compares some common digital resolutions. Digital technology has long had sufficient bandwidth and dynamic range to satisfy human hearing (Figure 1). We’re pros, right? We should be able to hear the difference between Switchcraft and Neutrik connectors, and we definitely deserve better than “CD Quality.” In reality, CD quality may not be as bad as you think. Many audio practitioners are insulted by the suggestion that “CD quality” is good enough for their golden ears. I will start by saying that this is a surprisingly controversial topic. Following is what we did, including some resources for replicating it on your own. The seminar has come and gone, and we did indeed conduct the demo. A fire storm ensued, and I posted that we would conjure up a digital resolution demonstration for the then upcoming SynAudCon Digital seminar, to be held in North Haven, CT. AOCS offers Quality Reference Samples with their respective reports for these and other uses.By Pat Brown Is “CD Quality” Good Enough? In this article, Pat give you an opportunity to compare between 16 to 24 bit.įlashback to earlier this spring when I started a discussion thread on the SAC Forum regarding digital audio resolution, citing a study that suggested that CD quality was sufficient to fully capture the frequency response and dynamic range detectable by humans. Obtaining known samples with reliable report results is key to training new people, calibrating equipment, testing new methods and a multitude of other lab testing activities. Canadian Lipids and Proteins Conference.Soybean 360: Agro Processing in Sub-Saharan Africa.
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