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Groups > comp.sys.apple2.programmer > #4513

Re: WAV file playback

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On Saturday, April 21, 2018 at 11:54:51 PM UTC-7, mjm...@aol.com wrote:
> Michael Pohoreski wrote:
> > 11,025 Hz requires = 17,030 * 29.97 / 11,025 = 46.293 cycles between speaker toggling.
> > 
> I think the OP’s meaning was that at a sample rate of 11.025 KHz, each
> sample must be played in (ideally) 92.5 Apple II cycles. 

Right. I just wanted to clarify that a "sample" means two speaker toggles since it wasn't explicitly clear. =P

> Of course, only integral numbers of cycles are possible, and the sample
> rate cannot alternate between 92 and 93 cycles, since the jitter would
> introduce spurious frequencies surrounding 5.5125 KHz. 

I'm assuming this related to following calculations?

92 cycles = 5547.707609 Hz
93 cycles = 5488.054839 Hz


> The best non-distorting choice is then 92 cycles per sample.

Interesting. How did you determine that?


> I found this convenient in DAC522, since 92 is an even number, 
> and I wanted to generate
> two speaker pulses (four toggles) for each sample. 

What was the duty cycle you used for 4 pulses?

> This raises the pulse
> frequency to 22.05 KHz, which is less annoying to most people “of an age”

I must be getting old, because I can't hear anything past ~14 KHz ... :-/

> (In the absence of “brick wall” filters, the practical top frequency is
> closer to 5 KHz.)

How did you determine that?

Cheers
Michael

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Thread

WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-19 12:15 -0700
  Re: WAV file playback Chris Vavruska <vavruska@gmail.com> - 2018-03-19 18:28 -0700
    Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-19 19:43 -0700
      Re: WAV file playback Michael J. Mahon <mjmahon@aol.com> - 2018-03-20 01:55 -0500
        Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-20 14:49 -0700
          Re: WAV file playback Michael J. Mahon <mjmahon@aol.com> - 2018-03-21 00:23 -0500
            Re: WAV file playback Tom Porter <laseractiveguy@gmail.com> - 2018-03-21 07:36 -0700
              Re: WAV file playback Michael J. Mahon <mjmahon@aol.com> - 2018-03-21 10:13 -0500
                Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-22 22:27 -0700
                Re: WAV file playback James Davis <JPD.Enterprises@outlook.com> - 2018-03-24 12:35 -0700
                Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-24 19:44 -0700
                Re: WAV file playback James Davis <JPD.Enterprises@outlook.com> - 2018-03-25 09:22 -0700
                Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-25 10:08 -0700
  Re: WAV file playback Tom Porter <laseractiveguy@gmail.com> - 2018-03-24 06:05 -0700
    Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-24 11:50 -0700
      Re: WAV file playback Michael J. Mahon <mjmahon@aol.com> - 2018-03-24 20:18 -0500
        Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-24 19:29 -0700
          Re: WAV file playback Michael J. Mahon <mjmahon@aol.com> - 2018-03-24 21:53 -0500
            Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-24 21:49 -0700
              Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-24 22:25 -0700
                Re: WAV file playback Michael J. Mahon <mjmahon@aol.com> - 2018-03-25 09:44 -0500
          Re: WAV file playback Michael J. Mahon <mjmahon@aol.com> - 2018-03-24 22:43 -0500
            Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-24 21:43 -0700
              Re: WAV file playback Michael J. Mahon <mjmahon@aol.com> - 2018-03-25 09:42 -0500
    Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-03-24 11:56 -0700
  WAV file playback Michael Pohoreski <michael.pohoreski@gmail.com> - 2018-04-21 21:01 -0700
    Re: WAV file playback Michael J. Mahon <mjmahon@aol.com> - 2018-04-22 01:54 -0500
      Re: WAV file playback Michael Pohoreski <michael.pohoreski@gmail.com> - 2018-04-22 22:33 -0700
        Re: WAV file playback Michael J. Mahon <mjmahon@aol.com> - 2018-04-23 12:19 -0500
      Re: WAV file playback Michael Pohoreski <michael.pohoreski@gmail.com> - 2018-04-22 22:53 -0700
        Re: WAV file playback "Frank M." <frank_o_rama@hotmail.com> - 2018-04-23 08:42 -0700
        Re: WAV file playback Michael J. Mahon <mjmahon@aol.com> - 2018-04-23 12:19 -0500
          Re: WAV file playback Michael Pohoreski <michael.pohoreski@gmail.com> - 2018-04-23 22:38 -0700

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