Need to convert audio files to speccy quality sound - Sinclair

This is a discussion on Need to convert audio files to speccy quality sound - Sinclair ; Hi. I've been experimenting with Spectrum sound sampling/digitizing for many years, but only with the available software, which was limited to a 6 second duration clip and used all the available ram. Recently I was told that Chase HQ and ...

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Thread: Need to convert audio files to speccy quality sound

  1. Need to convert audio files to speccy quality sound

    Hi. I've been experimenting with Spectrum sound sampling/digitizing for
    many years, but only with the available software, which was limited to
    a 6 second duration clip and used all the available ram.

    Recently I was told that Chase HQ and Robocop had almost noise-free
    digitized speech because they used the AY chip (first time I heard the
    AY chip could be used for something else than music). I was told that a
    instead of using the regular 1-bit sound capture, there are ways to do
    it with 4-bit and 7-bit. But the person couldn't tell me how.

    I know how to use emulators to run the old spectrum sampler software,
    digitize the 6sec clips, play them back in the emulators while
    capturing it to any pc sound editor, and edit and append all clips
    until I get the complete converted clip, but the process is time
    consuming.

    Is there a way to convert an audio file (for example, a wav, or a raw
    file) to a file that sounds like spectrum digitized sound? Even if it's
    just 1-bit quality, as long as I'm not limited by the 6sec issue, it
    would be great.

    I tried to resample audio files using available audio editors, but even
    with resampling and bit-depth reduction it still doesn't give the
    result that I need.

    I know the Spectrum ULA generates 1-bit quality sound, and I know that
    spectrum digitized sound appears in Goldwave like a 50% duty cycle
    square wave, but I don't know how to replicate that. I even made some
    experiments with expression evaluators, but couldn't reach good
    results.

    An example of digitized video with digitized speech (it's out of synch
    for now) can be seen here:

    http://smg.photobucket.com/albums/v4...p001uncwds.flv

    Any ideas or suggestions would be greatly appreciated.

    /Bruno


  2. Re: Need to convert audio files to speccy quality sound

    On 25 Jan 2007 22:54:12 -0800 da kidz on comp.sys.sinclair were rappin'
    to MC zxbruno:

    > Is there a way to convert an audio file (for example, a wav, or a raw
    > file) to a file that sounds like spectrum digitized sound? Even if it's
    > just 1-bit quality, as long as I'm not limited by the 6sec issue, it
    > would be great.


    Yes, there is. There is a WAV player for the Speccy on NVG - but
    you'll have to go hunting for it as I don't have time to find out
    exactly where it is right now.

    Chris


    --
    +-------------------------------------------+
    | Unsatisfactory Software - "because it is" |
    | http://www.unsatisfactorysoftware.co.uk |
    | Your Sinclair: A Celebration |
    +- http://www.yoursinclair.co.uk -----------+

    DISCLAIMER: I may be making all this stuff up again.

  3. Re: Need to convert audio files to speccy quality sound

    zxbruno escribió:

    > I tried to resample audio files using available audio editors, but even
    > with resampling and bit-depth reduction it still doesn't give the
    > result that I need.


    When you digitize music from the EAR input, the Spectrum generates a square
    wave, as you know, but the Spectrum is a bit deaf (take it literally ), as it
    requires that the input to reach and pass a certain voltage level to consider it
    "1". It's not merely "whatever it's above 0V is 1 and whatever it's below, 0".

    Try lowering the DC offset of the WAV audio, it may help "improving" the result.

    On the other hand, it's possible for the Spectrum to generate better output
    using PWM. I dont't know of games using this feature, as it requires more
    memory, and it's limited (on the Spectrum) to low sampling frequencies because
    of performance limits. PWM syntesis is more than many sound editors can achieve,
    and it would possibly need some custom software...


  4. Re: Need to convert audio files to speccy quality sound

    On 26 Jan 2007 07:23:18 +0000 da kidz on comp.sys.sinclair were rappin'
    to MC Chris Young:

    > Yes, there is. There is a WAV player for the Speccy on NVG - but
    > you'll have to go hunting for it as I don't have time to find out
    > exactly where it is right now.


    I think this is it:
    ftp://ftp.nvg.unit.no/pub/sinclair/u.../WAVPlayer.zip

    Chris

    --
    +-------------------------------------------+
    | Unsatisfactory Software - "because it is" |
    | http://www.unsatisfactorysoftware.co.uk |
    | Your Sinclair: A Celebration |
    +- http://www.yoursinclair.co.uk -----------+

    DISCLAIMER: I may be making all this stuff up again.

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