Oliver Schmidt <ol.sc@web.de> wrote:
> Hi,
>
> The other day I finalized A2Stream, a program that simultaneously
> receives a file from any HTTP server and plays it through the stock
> Apple II speaker circuit.
>
> Some personal background: For many years by now, I've developed and
> maintained Ethernet software for the Apple II. My focus was always on
> practicability, portability and reusablitiy. Often I've invested in
> tools, trying to enable others to create something cool. However, for
> once I wanted to do the opposite: Showing off with a tech demo that
> pushes boundaries.
>
> A2Stream follows the general concept of DAC522, but with an improved
> audio quality using pulse-width modulation at 22050Hz sample rate with
> ~5.17 bit resolution. This sample rate is kept consistent during the
> complete playback, so A2Stream is supposed to sound better than
> everything else using Apple II speaker circuit so far.
>
> Project site - https://github.com/oliverschmidt/A2Stream
> Demo video - https://youtu.be/YcYEnYsI-_M
>
> Have fun,
> Oliver
>

Oliver, this is amazing!

When I was building DAC522, I felt constrained to using 11kHz samples
because of memory limitations, and even then only a few seconds of sampled
sound would fit. That’s one reason why I wrote the wavetable synthesizers,
since they only required a limited palette of samples.

Streaming sound was unthinkable at the time, so I was blown away by
A2Stream!

Doubling the sample rate of course doubles the bandwidth, but I was really
surprised by the great fidelity and the noise reduction. At first hearing,
I thought I was listening to the source sound, not the playback!

And to do this while managing network sample streaming and an animation is
a remarkable programming feat. You’ve set a new benchmark for 8-bit Apple
II sound!

Congratulations! I hope you’ve inspired others by showing what can be
accomplished with skill and vision.

--
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com

Hi Michael,

>When I was building DAC522, I felt constrained to using 11kHz samples
>because of memory limitations, and even then only a few seconds of sampled
>sound would fit.

Yeah. Usually everything about the Apple II is about memory
limitations. So coming from programming the Uthernet cards, I was
asking myself: "What can be done with the Apple II if memory isn't
limited, if the CPU is the only limitation."

>And to do this while managing network sample streaming and an animation is
>a remarkable programming feat. You've set a new benchmark for 8-bit Apple
>II sound!
>
>Congratulations! I hope you've inspired others by showing what can be
>accomplished with skill and vision.

I really, really appreciate your kind acknowledgement :-)

Regards,
Oliver