• NaibofTabr@infosec.pub
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    6 months ago

    D/A and A/D | Digital Show and Tell (Monty Montgomery @ xiph.org)

    This is a video about the digital vs analog audio quality debate. It explains, with examples, why analog audio within the accepted limits of human hearing (20 Hz to 20 kHz) can be reproduced with perfect fidelity using a 44.1 kHz 16 Bit digital signal.

    There is no audible difference between an analog and digital audio signal.

    Among other things, xiph.org maintains the .flac and .ogg vorbis audio formats - they know a little about audio encoding and reproduction.

    • vulpivia@lemmy.world
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      5 months ago

      It’s actually because of the limitations of analog media that analog audio might sound better. For example, you can’t compress the signal as much when mastering for vinyl instead of digital, since you risk the needle jumping between adjacent grooves. As a result, the vinyl version of a song can sound more dynamic.

      • Carnelian@lemmy.world
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        5 months ago

        It’s the opposite, no? Vinyl can’t handle the explosive dynamics common in modern music (especially electronic) due to the skipping issue, so any sharp peaks like that need to be compressed to make the overall mix more mellow

        • vulpivia@lemmy.world
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          5 months ago

          I did a bit of reading and it seems you’re right, but it isn’t quite as simple. You have to compress more, since you have less potential dynamic range on vinyl (so in practice a digital recording can be more dynamic than an analog one), but limiting is more problematic and an excessively limited recording has to be cut quieter or you’ll encounter issues. From what I read, these issues seem to be mainly unintended distortion and, again, needle skipping.

          But your explanation makes sense and I’m not quite sure why excessive limiting would lead to skipping.

          • Carnelian@lemmy.world
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            5 months ago

            So, a limiter and a compressor are actually the same thing! Just used in different contexts. You can think of a limiter as being a compressor set to extreme values, so that you can guarantee that at no point will the volume go beyond a certain threshold.

            So let’s think of like, a guitar string being plucked. It starts out loud and percussive, you get some string noise as well. Then the actual tone is played, starts as loud as it will ever get, then gradually reduces in volume over time naturally as the energy in the string is lost.

            Suppose we set the limiter to be a very low threshold, just above the quiet ringing you would hear after like 15 seconds of letting the guitar string resonate. Essentially the limiter will aggressively turn down the volume during the whole beginning, then ease off as the tone naturally quiets.

            The final result is that you’ve transformed a sound wave that started out with a large amplitude that gradually got smaller, into one that has a generally uniform amplitude throughout its entire duration! Then, as with all compressors, since you’ve actually reduced the amplitude of the wave, you can now turn the volume waaaaaaay up without clipping out. So now, stuff that used to be quiet is now just as loud as the loudest parts of your recording. A rustling leaf would be played at the same volume as a gunshot.

            The issue this creates with vinyl is that carving such an extreme waveform into a physical medium results in a path the needle simply can’t follow accurately.

            Imagine an old wooden roller coaster, one in which the cart isn’t attached to the track other than by gravity holding it there. If you included a sudden massive drop when the cart was moving at high speed, it wouldn’t follow the track, it would actually fly off the track briefly as it can only accelerate downward as fast as gravity will allow.

            If the needle is the cart, and the carving in the vinyl is the track, these moments of air time will create audible distortion. It’s actually a bit more precarious than that, even, as vinyls actually use not only the up and down components of gravity, but left and right as well. The two tracks superimposed are what allows us to create a stereo image (having distinct sounds in the left and right speakers).

            There’s also a ton of other things that can cause distortion, but I don’t want to ramble on forever! The basic rule of thumb is that a vinyl master essentially just has less low end. From what I understand, this is the root of why many people prefer “the sound” of vinyl, they simply prefer a slightly more mid-dominant mix