7 ms·

I remember wondering whether a laser "needle" could work. IIRC the format has some funky EQ and other things to make a physical needle work better.

marcodiego 5y ago
Already exists: https://en.wikipedia.org/wiki/Laser_turntable https://en.wikipedia.org/wiki/Laser_turntable
voldacar 5y ago
not cheap, but yeah it works great. https://www.elpj.com/ https://www.elpj.com/ I actually got to hear one once. Extremely neutral and high-res, but the record has to be super clean because with the laser, you will hear every little speck of dust. Also it doesn't work with colored vinyl, iirc. edit: they use 5 different lasers to get the data out of the groove, go read the section on their site, it's actually really intricate and cool > the format has some funky EQ and other things to make a physical needle work better Yes, in order to fit the high bandwidth music signal into a groove with a fixed width, the bass is EQed down and treble EQed up, since for a constant velocity sine wave, a low frequency wave would take up more physical width on the record than a high frequency wave. Without this EQ, you would only be able to store a small amount of music on a record. When the record is played, your phono preamp applies an inverted EQ curve to restore the signal to its original frequency response. In the past, there were lots of different vinyl equalization curves, but the RIAA curve has been standard for decades now. https://en.wikipedia.org/wiki/RIAA_equalization https://en.wikipedia.org/wiki/RIAA_equalization
- 11thEarlOfMar 5y ago
  "The record has to be super clean..." Audiophiles likely know of this, but I'm still surprised. Clean vinyl records with glue... https://everyrecordtellsastory.com/2015/05/25/how-to-deep-clean-your-vinyl-records-with-wood-glue-and-ten-things-that-you-shouldnt-use-to-clean-your-lps/ https://everyrecordtellsastory.com/2015/05/25/how-to-deep-cl...
  - DavidVoid 5y ago
    Cleaning with glue seems like much more of a hassle than using something like a SpinClean. If you want to thoroughly clean a vinyl record though, then an ultrasonic cleaner is the way to go (it is expensive though).
    - dogma1138 5y ago
      Cleaning with glue isn’t that difficult, buy the arts and crafts acrylic white glue mix it with water and spray it on the record (30% water / 70% glue works for me). Silly putty can also work in a pinch but some of them leave an oily residue. Spin clean works but the cheap machines can easily break the record and the expensive ones are expensive as fuck and can still result in damage due to user error.
- TylerE 5y ago
  Noise is also a big part of the RIAA curve. Almost all the noise on a record is high frequency...so by applying a strong treble rolloff most of it just disappears.
  - voldacar 5y ago
    Yes that's also very important - the inverted EQ applied by the phono preamp pushes the noise floor way down in the treble, while raising it in the bass. In my opinion, this is probably why vinyl can never compete with digital when it comes to clean-sounding bass, but can generally have equally detailed treble when cared for well and played on a good turntable
  - dylan604 5y ago
    Sounds like DolbyNR for cassettes. What high hats?
    - TylerE 5y ago
      It's a lot more clever than that. Because the music has the exact inverse transform applied it before it's cut to the master, you don't lose any signal, just noise.
      - aidenn0 5y ago
        Dolby NR was intended to be that way as well, but turning Dolby (type C) NR on removes tape-hiss from non-dolby tapes while also as GP said fading certain frequencies.
- Syzygies 5y ago
  Slide/negative scanners use multiple passes and depth perception to cleanly ignore dust on film. I'm surprised that this wasn't part of ELP's spec to the engineers. A giant fail if they can't even remove this noise in post-processing.
  - voldacar 5y ago
    There's no AD step in the ELP. it's an analog system from the laser to the line out. So there's no way to do multiple passes while listening to the record, though you can adjust the depth in the groove that the laser scans.
- LeoPanthera 5y ago
  > it works great. It does not work great. The problem is dirt, which sounds like a minor issue, but it renders the concept almost completely useless. A stylus pushes dirt out of the groove as the record turns. A laser cannot do so, and it's virtually impossible to fully clean a record. The only remaining advantage is that a laser turntable does not wear out the disc, and it's an incredibly minor advantage, compared to simply playing a record once on a traditional player, and recording the output.
  - voldacar 5y ago
    Like I said, I literally heard it. The guy cleaned the record just before playing it and it sounded amazing. Doing that each time would be a huge hassle so I'm not sure if I would ever want to own one. But I did hear it, and it did work great.
- m463 5y ago
  I wonder if they could do what film scanners do - they use an IR channel. EDIT: and as soon as I submitted I realize film scanners scan for light and maybe use the IR channel for physical scanning. with a record everything is physical. or maybe the IR channel focuses on a different plane? could they use different wavelengths for distance sensing/separation?
- tinus_hn 5y ago
  So how did this work when the ‘amplifier’ was just a giant horn?
  - phs2501 5y ago
    Early 78RPM records only played for a few minutes per side, the grooves were very widely spaced.
- stevage 5y ago
  Surprised they can't just build in a little dust blower or a little brush or something to clean the surface just before it gets read.
philjohn 5y ago
The funky EQ is the RIAA curve[1] - by essentially rolling off the bass and boosting the treble you can fit more on a disc, it attenuates some of the clicks and pops and is kinder on the vinyl and needle. It's trivial to invert in software, and as another response points out, there is indeed a working laser record player - although the record needs to be extensively cleaned before playback or it doesn't work very well. [1] https://en.wikipedia.org/wiki/RIAA_equalization https://en.wikipedia.org/wiki/RIAA_equalization
- dehrmann 5y ago
  This is part of what people hear when they say "vinyl sounds better."
  - andrewzah 5y ago
    That doesn't make any sense. RIAA EQ is a serialization format, that is then decoded by your audio equipment. That's what the phono jack is for on a receiver, pre-amp, etc. What people "hear" regarding LPs is generally their biases + their particular analog setup. My setup is going to sound totally different than yours, regardless if it's from a CD or an LP. There are some cases where an LP had a better -master- than a CD for the same release, but that is due to the publisher/owner of the master tracks and not the actual medium itself.
    - Yaa101 5y ago
      I found out when digitizing vinyl that LP's before 1977, when digital mixing and mastering was not the norm that there is more data in the frequencies between 20 and 50kHz. I do my recording standard at 192kHz and analogue LP's often reach 48kHz of data while digital mastered ones do only 22kHz. After that date often the frequency is cutoff at 20-22kHz, probably to save memory room. Only after 2000-2010 there is enough memory to record at insane sample rates and bits per sample. Most awful are cds having only 16 bits and 41kHz sample rate, by modern standards really poor.
      - 5y ago

marcodiego 5y ago

Already exists: https://en.wikipedia.org/wiki/Laser_turntable https://en.wikipedia.org/wiki/Laser_turntable

voldacar 5y ago

not cheap, but yeah it works great. https://www.elpj.com/ https://www.elpj.com/ I actually got to hear one once. Extremely neutral and high-res, but the record has to be super clean because with the laser, you will hear every little speck of dust. Also it doesn't work with colored vinyl, iirc. edit: they use 5 different lasers to get the data out of the groove, go read the section on their site, it's actually really intricate and cool > the format has some funky EQ and other things to make a physical needle work better Yes, in order to fit the high bandwidth music signal into a groove with a fixed width, the bass is EQed down and treble EQed up, since for a constant velocity sine wave, a low frequency wave would take up more physical width on the record than a high frequency wave. Without this EQ, you would only be able to store a small amount of music on a record. When the record is played, your phono preamp applies an inverted EQ curve to restore the signal to its original frequency response. In the past, there were lots of different vinyl equalization curves, but the RIAA curve has been standard for decades now. https://en.wikipedia.org/wiki/RIAA_equalization https://en.wikipedia.org/wiki/RIAA_equalization

11thEarlOfMar 5y ago
"The record has to be super clean..." Audiophiles likely know of this, but I'm still surprised. Clean vinyl records with glue... https://everyrecordtellsastory.com/2015/05/25/how-to-deep-clean-your-vinyl-records-with-wood-glue-and-ten-things-that-you-shouldnt-use-to-clean-your-lps/ https://everyrecordtellsastory.com/2015/05/25/how-to-deep-cl...
- DavidVoid 5y ago
  Cleaning with glue seems like much more of a hassle than using something like a SpinClean. If you want to thoroughly clean a vinyl record though, then an ultrasonic cleaner is the way to go (it is expensive though).
  - dogma1138 5y ago
    Cleaning with glue isn’t that difficult, buy the arts and crafts acrylic white glue mix it with water and spray it on the record (30% water / 70% glue works for me). Silly putty can also work in a pinch but some of them leave an oily residue. Spin clean works but the cheap machines can easily break the record and the expensive ones are expensive as fuck and can still result in damage due to user error.
TylerE 5y ago
Noise is also a big part of the RIAA curve. Almost all the noise on a record is high frequency...so by applying a strong treble rolloff most of it just disappears.
- voldacar 5y ago
  Yes that's also very important - the inverted EQ applied by the phono preamp pushes the noise floor way down in the treble, while raising it in the bass. In my opinion, this is probably why vinyl can never compete with digital when it comes to clean-sounding bass, but can generally have equally detailed treble when cared for well and played on a good turntable
- dylan604 5y ago
  Sounds like DolbyNR for cassettes. What high hats?
  - TylerE 5y ago
    It's a lot more clever than that. Because the music has the exact inverse transform applied it before it's cut to the master, you don't lose any signal, just noise.
    - aidenn0 5y ago
      Dolby NR was intended to be that way as well, but turning Dolby (type C) NR on removes tape-hiss from non-dolby tapes while also as GP said fading certain frequencies.
Syzygies 5y ago
Slide/negative scanners use multiple passes and depth perception to cleanly ignore dust on film. I'm surprised that this wasn't part of ELP's spec to the engineers. A giant fail if they can't even remove this noise in post-processing.
- voldacar 5y ago
  There's no AD step in the ELP. it's an analog system from the laser to the line out. So there's no way to do multiple passes while listening to the record, though you can adjust the depth in the groove that the laser scans.
LeoPanthera 5y ago
> it works great. It does not work great. The problem is dirt, which sounds like a minor issue, but it renders the concept almost completely useless. A stylus pushes dirt out of the groove as the record turns. A laser cannot do so, and it's virtually impossible to fully clean a record. The only remaining advantage is that a laser turntable does not wear out the disc, and it's an incredibly minor advantage, compared to simply playing a record once on a traditional player, and recording the output.
- voldacar 5y ago
  Like I said, I literally heard it. The guy cleaned the record just before playing it and it sounded amazing. Doing that each time would be a huge hassle so I'm not sure if I would ever want to own one. But I did hear it, and it did work great.
m463 5y ago
I wonder if they could do what film scanners do - they use an IR channel. EDIT: and as soon as I submitted I realize film scanners scan for light and maybe use the IR channel for physical scanning. with a record everything is physical. or maybe the IR channel focuses on a different plane? could they use different wavelengths for distance sensing/separation?
tinus_hn 5y ago
So how did this work when the ‘amplifier’ was just a giant horn?
- phs2501 5y ago
  Early 78RPM records only played for a few minutes per side, the grooves were very widely spaced.
stevage 5y ago
Surprised they can't just build in a little dust blower or a little brush or something to clean the surface just before it gets read.

philjohn 5y ago

The funky EQ is the RIAA curve[1] - by essentially rolling off the bass and boosting the treble you can fit more on a disc, it attenuates some of the clicks and pops and is kinder on the vinyl and needle. It's trivial to invert in software, and as another response points out, there is indeed a working laser record player - although the record needs to be extensively cleaned before playback or it doesn't work very well. [1] https://en.wikipedia.org/wiki/RIAA_equalization https://en.wikipedia.org/wiki/RIAA_equalization

dehrmann 5y ago
This is part of what people hear when they say "vinyl sounds better."
- andrewzah 5y ago
  That doesn't make any sense. RIAA EQ is a serialization format, that is then decoded by your audio equipment. That's what the phono jack is for on a receiver, pre-amp, etc. What people "hear" regarding LPs is generally their biases + their particular analog setup. My setup is going to sound totally different than yours, regardless if it's from a CD or an LP. There are some cases where an LP had a better -master- than a CD for the same release, but that is due to the publisher/owner of the master tracks and not the actual medium itself.
  - Yaa101 5y ago
    I found out when digitizing vinyl that LP's before 1977, when digital mixing and mastering was not the norm that there is more data in the frequencies between 20 and 50kHz. I do my recording standard at 192kHz and analogue LP's often reach 48kHz of data while digital mastered ones do only 22kHz. After that date often the frequency is cutoff at 20-22kHz, probably to save memory room. Only after 2000-2010 there is enough memory to record at insane sample rates and bits per sample. Most awful are cds having only 16 bits and 41kHz sample rate, by modern standards really poor.
    - 5y ago