Yesterday, my post was a mini test. It consisted of 10 questions…a few True and False questions and a bunch of multiple choice questions. The students at the university would love to see me prepare a test full of multiple choice questions…but I required them to write out their answer. Consider yourselves lucky.
Here’s the answers:
Question 1: The correct answer is letter “B” or 60 dB. Analog tape machines are not very good at capturing dynamics.
Question 2: None of the formats listed in this question qualify as high-resolution. DSD 64 comes the closest but because of the excessive noise that exists in the ultrasonic frequency range, I leave it out. The correct answer is letter “E”.
Question 3: False. Analog recordings don’t gain dynamic range just because they’ve been transferred to a large digital bit bucket.
Questions 4: The correct answer is 4-bits or letter “D”. The mastering process used on commercial release reduces the overall dynamic range of virtually all CDs to less than 10-12 bits or less than 4-bits.
Question 5: The answer is letter “A”. The Dolby Digital or AC-3 encoding scheme is a lossy algorithm and therefore doesn’t reproduce all of the fidelity that was contained in the original source recording.
Question 6: The correct answer is “D”. If the substance that you use on your optical discs cleans the surface and is completely removed from the surface after use, then it might result in better transmission of data from the “pits” of the disc to the optical pickup. The rest of the items on the list were actually taken from published statements about these products, from magazine reviews, or from customer testimonials.
Question 7: False. This notion is very widely believed by analogophiles. It’s patently false. Both statements are false. We don’t measure analog system with terms like resolution AND there are no stair steps in a PCM digital recording when it’s converted back to analog (in fact the data isn’t stair steps either).
Question 8: False: Moving from 16-bits to 24-bits lowers the noise floor and provides a safer margin from overages and distortion for recording engineers during sessions.
Question 9: The correct answer is “E” or all of the above. Dither is a very useful technique for removing or masking quantization noise and spreading it across the entire frequency spectrum.
Question 10: False. Although this statement has been widely used on website and promotional brochures that advocate for DSD, the fact is that DSD 64 recordings or SACD have about the same specifications and fidelity as a standard CD.
So how did you do? I’m expecting to receive some push back from some of you on several of these questions. So go ahead and let’s discuss.
As for grading…here’s how I would score things:
9-10 correct deserves and A
8 correct earns a B
7 gets a C
6 out of 10 lets you squeak through with a D
and anything less means you fail.
I hope you enjoyed the Audiophile Midterm. Keep studying and we’ll have the final exam in a few months.