In order to test our 8 bit DAC I played a bit with at67’s miditones / gtmidi / gtbasic toolchain.
The following sample was recorded from the output of the audio module by means of Audacity for Windows
This is the standard output of the Gigatron for comparison:
6Bit audio:
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Be nice. No drama.
Be nice. No drama.
Re: 6Bit audio:
Awesome, the difference in quantisation noise is clearly audible, it sounds like you're using Sine waves as the channel samples?
Re: 6Bit audio:
Sounds pretty convincing.
Is there a way to say how much is related to the additional bits, and how much to the better analog circuitry?
That said, my understanding is that Marcel's code treats each channel as 6 bits (saturating at 63). Adding four channels yield 8 bits before truncating the low 4 bits. Therefore, if one only uses one channel, only 2 bits are really used. At67's demos seem smarter than that though...
Is there a way to say how much is related to the additional bits, and how much to the better analog circuitry?
That said, my understanding is that Marcel's code treats each channel as 6 bits (saturating at 63). Adding four channels yield 8 bits before truncating the low 4 bits. Therefore, if one only uses one channel, only 2 bits are really used. At67's demos seem smarter than that though...
Re: 6Bit audio:
I used a sine wave in waveform 2 as in your Music64k example !
The main improvement in respect to sound quality is certainly due to the better resolution of the DAC. An audible difference between 6 and 8 bit may depend on the sound sample preparation, though.
In addition low-pass filtering on the audio board very effectively suppresses high pitch noise. This makes the sound more pleasant - especially when directly connecting headphones to the board.
The main improvement in respect to sound quality is certainly due to the better resolution of the DAC. An audible difference between 6 and 8 bit may depend on the sound sample preparation, though.
In addition low-pass filtering on the audio board very effectively suppresses high pitch noise. This makes the sound more pleasant - especially when directly connecting headphones to the board.