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Thread: Does something like this exist - cassette emulation using sd card?

  1. #11
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    MP3? Seriously? You would want a high-bit-rate MP3, since the MP3 codec is designed to use human ear response perceptual compression. I personally wouldn't recommend using MP3 for storing data audio streams. You're better off with 8k bandwidth mono WAV or FLAC files. MPEG I Layer 3 compression at the lower bitrates especially could wreak havoc on the data stream.

    For WAV, you could use something like an Edirol R-09 or equivalent that can record and playback uncompressed WAV and that has the 1/8 inch input and headphone jacks. Alternatives would include the Zoom H1, H4, or H6; there are many units available at multiple price points that can do a great WAV recording (you only need 16-bit; 24-bit is typically used for audio production purposes when you know the audio file is going to be used as source material for nonlinear processing). I own an Edirol R-09, but I've not used it for data cassette emulation as yet. I also own a Roland R-26, which is overkill for cassette emulation.....

    The only thing you'll not have on one of these units would be the aux motor start; you just have to hit play and record manually, like many people did back in the day.
    --
    Bughlt: Sckmud
    Shut her down Scotty, she's sucking mud again!

  2. #12

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    Quote Originally Posted by freaktmp View Post
    I have three tape emulators.
    Arduitape is a generic tape emulator. It supports playback of wav files (up to 22.5kHz) to microsd card. No recording support. Available on Etsy.
    That is interesting - it even looks like it has an aux jack. Why only a single 1/8" jack though? Do you use it for both recording and playback?

  3. #13
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    As I said, there is no recording support.

    There is no aux, it is a rem jack for motor control emulation.

  4. #14

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    Not sure if this is overkill, but what about a thin client with audio jacks, running linux/windows. Record/Playback to your hearts content.
    Looking for: OMTI SMS Scientific Micro Systems 8610 or 8627 ESDI ISA drive controller, May also be branded Core HC, Please PM me if you want to part with one.

  5. #15

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    Quote Originally Posted by lowen View Post
    MP3? Seriously? You would want a high-bit-rate MP3, since the MP3 codec is designed to use human ear response perceptual compression. I personally wouldn't recommend using MP3 for storing data audio streams. You're better off with 8k bandwidth mono WAV or FLAC files. MPEG I Layer 3 compression at the lower bitrates especially could wreak havoc on the data stream.
    You'd be surprised. I've done exactly this with MP3 at bitrates from 56 kbps to 80 kbps with Sinclair ZX Spectrum recordings. Losslessly too, if you know what you're doing...

  6. #16
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    Quote Originally Posted by cthulhu View Post
    You'd be surprised. I've done exactly this with MP3 at bitrates from 56 kbps to 80 kbps with Sinclair ZX Spectrum recordings. Losslessly too, if you know what you're doing...
    Same here. I have a mix of WAV and MP3 files I use with Apple-1, Apple II, Sol-20, ALTAIR and even PCjr using an iPod Mini or iPod 20gb HD. Sometimes I use my iPhone, but then I have to find that stupid adapter because I don’t have a headphone jack.

  7. #17

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    MP3 is most likely Ok for those that do the typical two tone signals. This is the commonly at a 300 data rate. The Poly 88 also does a 2400 data rate that does a phase encoding. It doesn't do well with MP3. It is even fussy about the tape recorder. Those that erase by dragging a magnet on the tape never work. It does do both types so one can get by with the cheaper recorders.
    Dwight

  8. #18

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    Quote Originally Posted by Dwight Elvey View Post
    The Poly 88 also does a 2400 data rate that does a phase encoding. It doesn't do well with MP3.
    I'm sure it'd work fine with my method. As I mentioned before it is possible to encode these sorts of signals using an MP3 encoder in such a way that they are decoded to the exact same signal, i.e. lossless compression.

  9. #19
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    Quote Originally Posted by retro-pc_user View Post
    They should make Minidiscs that can utilize SD cards (I have a Sony Minidisc Player/Recorder that I got last year for $10 at a thrift store).
    I'm not sure you understand how a Minidisc works......
    = Excellent space heater

  10. #20
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    Quote Originally Posted by cthulhu View Post
    You'd be surprised. I've done exactly this with MP3 at bitrates from 56 kbps to 80 kbps with Sinclair ZX Spectrum recordings. Losslessly too, if you know what you're doing...
    So, what sorts of encoder settings are you using to get 'lossless' MP3 encoding of the data audio (for that matter, which encoder; LAME, perhaps?)? (When it comes to the audio side, I do know what I'm doing; I've been a broadcast engineer for 28 years, 10 years of which was full-time, and am very familiar with variouls compression technologies and their audible effects). Which cassette data standard?

    For LAME, I might be inclined to try the following parameters:
    Code:
    -m m -q 0 -b 64 --cbr --lowpass 8 --highpass 0.1 --resample 22.05
    (this assumes the original capture was done at 44.1; for other capture sample rates, use a suitable even submultiple for the --resample parameter, as long as it's at least 16).
    --
    Bughlt: Sckmud
    Shut her down Scotty, she's sucking mud again!

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