Showing posts with label cd. Show all posts
Showing posts with label cd. Show all posts

Friday, July 31, 2026

My first iFixit guide

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Sony CDP-CE375 Belt Replacement

Sony's CDP-CE375 is a great 5-disc CD changer. But over time, its two belts (loading belt for opening the drawer and rotary belt rotating the disc-tray) can stretch, preventing the device from operating properly.

This guide shows how to replace both belts.

I'm very proud of this. Both for repairing my CD player and for writing what I think is a very good guide for others to follow.

Friday, January 15, 2016

YouTube: CD Shattering captured at 170,000 frames per second

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Gav and Dan present the SLOWEST EVER episode of the slow mo guys by spinning a disc at 23,000RPM and filming it shatter at a whopping 170,000 frames per second.

We all know that a CD (and just about anything else) will shatter if you spin it fast enough. This video uses an ultra high-speed camera to capture the shatter. It looks amazing.

Friday, March 14, 2014

xiph: 24/192 Music Downloads ...and why they make no sense

2 comments:
Another article (this one from March 2012) about high-definition audio, sampling rates, human hearing, and why the CD-standard format is a really good format for distributing audio.

Some notable quotes:

Unfortunately, there is no point to distributing music in 24-bit/192kHz format. Its playback fidelity is slightly inferior to 16/44.1 or 16/48, and it takes up 6 times the space.

Yes, this surprised me too. Unnecessary, I agree, but inferior?. As it turns out, inaudible ultrasonic content frequencies can cause intramodular distortion that may be audible unless you've got very high-end equipment that can cleanly reproduce it.

The concept is similar to how high/mid/low frequencies can interfere with each other, which is why most good amplifiers and speakers use separate discrete components (along with appropriate filters and crossovers) to process these ranges independently.

The article also talks about how 16 bits really is enough to capture the full dynamic range a human ear is capable of hearing:

16 bit linear PCM has a dynamic range of 96dB according to the most common definition, which calculates dynamic range as (6*bits)dB. Many believe that 16 bit audio cannot represent arbitrary sounds quieter than -96dB. This is incorrect.
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With use of shaped dither, which moves quantization noise energy into frequencies where it's harder to hear, the effective dynamic range of 16 bit audio reaches 120dB in practice, more than fifteen times deeper than the 96dB claim.

120dB is greater than the difference between a mosquito somewhere in the same room and a jackhammer a foot away.... or the difference between a deserted 'soundproof' room and a sound loud enough to cause hearing damage in seconds.

And has so much range that any recording actually using it would be annoying to listen to in a normal room - I'd be constantly turning the volume up (to hear the quiet parts) and down (to avoid pain during the loud parts.) Just like I sometimes have to do when listening to music in the car or when trying to watch a movie while others are talking in the same room.

I would contend that 16-bits is more than sufficient, because audio that is comfortable to listen to in an uncontrolled environment should be compressed to less thaneven 96dB. (Although the high dynamic range is definitely welcome when I'm in a quiet room listening on good equipment.)

Finally, I want to quote a section on how loudness can impact preferences. I always knew that people tend to prefer louder sound, but I didn't realize how subtle the changes can be, and why you can't eliminate this factor from audio testing without specialized equipment:

The human ear can consciously discriminate amplitude differences of about 1dB, and experiments show subconscious awareness of amplitude differences under .2dB. Humans almost universally consider louder audio to sound better, and .2dB is enough to establish this preference. Any comparison that fails to carefully amplitude-match the choices will see the louder choice preferred, even if the amplitude difference is too small to consciously notice. Stereo salesmen have known this trick for a long time.

The professional testing standard is to match sources to within .1dB or better. This often requires use of an oscilloscope or signal analyzer. Guessing by turning the knobs until two sources sound about the same is not good enough.

Please read the complete article including the footnotes. There's a lot of great information in here.

If people want to switch to a new audio format that sounds better than the MP3s they have now, they would be best off by simply re-ripping their CDs into a lossless format like FLAC or Apple Lossless. By simply removing all compression artifacts, you will get audio that will sound great if your playback equipment is up to the task.

Wednesday, February 26, 2014

Mix: The Emperor's New Sampling Rate

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Audiophiles have been singing the praises of various high-definition audio formats (SACD, DVD-A, 96KHz sampling, 192KHz sampling, 24-bit, etc.) for years, while others have claimed that it's all hype and wishful thinking.

A double-blind study (from 2008) demonstrates (and to me, proves) that the nay-sayers are right and the audiophiles are wrong.

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According to a remarkable new study, however, the failure of new audio formats — at least the ones that claim superiority thanks to higher sample rates — to succeed commercially may in reality be meaningless. The study basically says that (with apologies to Firesign Theatre) everything you, I, Moorer and everyone else know about how much better high-sample-rate audio sounds is wrong.

The study was published in this past September's Journal of the Audio Engineering Society under the title "Audibility of a CD-Standard A/D/A Loop Inserted Into High-Resolution Audio Playback."
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It was designed to show whether real people, with good ears, can hear any differences between “high-resolution” audio and the 44.1kHz/16-bit CD standard. And the answer Moran and Meyer came up with, after hundreds of trials with dozens of subjects using four different top-tier systems playing a wide variety of music, is, “No, they can't.”
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