3 ms·

Can someone explain why this doesn't distort the signal? Eg. with all these capacitors one might think it would filter out higher frequencies?

duped 2y ago
It does. It also obeys the Shannon-Nyquist sampling theorem when you take into account the clock frequency (you can't delay signals above half the clock frequency). It also exhibits nonlinearities that will create harmonic distortion. At least in the pro audio space, those qualities are actually desirable.
- atoav 2y ago
  They can be desirable. If I want to normalize the group delay of a bunch of drum mics, I sure as hell not gonna use a BBD-Delay for it. But if I want a flavourful analog delay onna guitar track, why not.
  - pierrec 2y ago
    >a nunch ofndrum mkcs "Am I having a stroke" comes to mind :) A bunch of drum mics? I'm no recording engineer, but I guess this is about mixing different signals from the same setup, with the signals having different delays (possibly due to filters, cables, or different types of mics)
    - brudgers 2y ago
      Distance. Microphones at different distances receive a signal at different times. When combined, the signals are not phase aligned. This causes comb filtering where the combined waves reinforce and cancel each other. Though that is sometimes desirable (e.g. comb filtering is important for spatial ambience such as reverb). Some audio engineers find careful microphone placement solves many potential problems. Drums are notoriously hard because modern recording techniques use many microphones on a kit.
    - atoav 2y ago
      Corrected — smartphone keyboards suck. Yeah this is about phase alignment of multiple sources. brudgers comment explains it quite eloquently.
  - brudgers 2y ago
    if I want a flavourful analog delay Sounds like use.
- ggeorgovassilis 2y ago
  Makes sense, thank you!
- ericwood 2y ago
  It’s worth noting that in addition to the sample rate, the companding to improve SNR and filtering techniques for anti-aliasing and reconstruction usually employed to (attempt to) retain signal integrity play a large part in the character. A lot of people think of them as “dark” but that voicing can vary a lot between delays depending on how the designer chose to bandwidth limit it; therein lies the real art of analog delay! I’ve been working on an MN3205 with digital controls and pushing it well past its reasonable specs is very fun; 4096 stages really starts to fall apart past 300ms, and when you clock it down to more than a single second you get a wet robot fart out of the other end!
  - loxias 2y ago
    > I’ve been working on an MN3205 with digital controls... I should get myself some of those to play with, and you, friend, might enjoy a tape delay or two off ebay. (I have an Echoplex and it's tons of fun)
    - ericwood 2y ago
      Highly recommend it! The chips themselves aren't the cheapest but xvive and coolaudio are still cranking them out so you don't have to resort to tracking down NOS parts. Complimentary PWM from a microcontroller and a gate driver for the clock pins (the MN3205 has 2800pF input capacitance) and you're in business! I'm always on the lookout for a deal on a space echo or echorec! Keeping them in working condition is not the easiest unfortunately, and it's tough to justify the real thing when incredible emulations exist (I highly recommend the Strymon Volante for scratching that itch)
      - wrs 2y ago
        And there’s Echo Fix. I’ve resisted temptation so far, but…

duped 2y ago

It does. It also obeys the Shannon-Nyquist sampling theorem when you take into account the clock frequency (you can't delay signals above half the clock frequency). It also exhibits nonlinearities that will create harmonic distortion. At least in the pro audio space, those qualities are actually desirable.

atoav 2y ago
They can be desirable. If I want to normalize the group delay of a bunch of drum mics, I sure as hell not gonna use a BBD-Delay for it. But if I want a flavourful analog delay onna guitar track, why not.
- pierrec 2y ago
  >a nunch ofndrum mkcs "Am I having a stroke" comes to mind :) A bunch of drum mics? I'm no recording engineer, but I guess this is about mixing different signals from the same setup, with the signals having different delays (possibly due to filters, cables, or different types of mics)
  - brudgers 2y ago
    Distance. Microphones at different distances receive a signal at different times. When combined, the signals are not phase aligned. This causes comb filtering where the combined waves reinforce and cancel each other. Though that is sometimes desirable (e.g. comb filtering is important for spatial ambience such as reverb). Some audio engineers find careful microphone placement solves many potential problems. Drums are notoriously hard because modern recording techniques use many microphones on a kit.
  - atoav 2y ago
    Corrected — smartphone keyboards suck. Yeah this is about phase alignment of multiple sources. brudgers comment explains it quite eloquently.
- brudgers 2y ago
  if I want a flavourful analog delay Sounds like use.
ggeorgovassilis 2y ago
Makes sense, thank you!
ericwood 2y ago
It’s worth noting that in addition to the sample rate, the companding to improve SNR and filtering techniques for anti-aliasing and reconstruction usually employed to (attempt to) retain signal integrity play a large part in the character. A lot of people think of them as “dark” but that voicing can vary a lot between delays depending on how the designer chose to bandwidth limit it; therein lies the real art of analog delay! I’ve been working on an MN3205 with digital controls and pushing it well past its reasonable specs is very fun; 4096 stages really starts to fall apart past 300ms, and when you clock it down to more than a single second you get a wet robot fart out of the other end!
- loxias 2y ago
  > I’ve been working on an MN3205 with digital controls... I should get myself some of those to play with, and you, friend, might enjoy a tape delay or two off ebay. (I have an Echoplex and it's tons of fun)
  - ericwood 2y ago
    Highly recommend it! The chips themselves aren't the cheapest but xvive and coolaudio are still cranking them out so you don't have to resort to tracking down NOS parts. Complimentary PWM from a microcontroller and a gate driver for the clock pins (the MN3205 has 2800pF input capacitance) and you're in business! I'm always on the lookout for a deal on a space echo or echorec! Keeping them in working condition is not the easiest unfortunately, and it's tough to justify the real thing when incredible emulations exist (I highly recommend the Strymon Volante for scratching that itch)
    - wrs 2y ago
      And there’s Echo Fix. I’ve resisted temptation so far, but…