Karplus Strong guitar project, beautiful sound but what's the bit resolution?

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It uses the 8 bit timer/counter0 (of Atmega644P) to generate the PWM. So the bit resolution would be 8 bits.
The PWM frequency also matches with this information: 20MHz / (2^8) = 78 kHz
 
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That's what I thought, but it certainly does not sound like a 8bit. I wonder how it would sound at 44khz sampling rate instead of 78khz. I still can't figure out what the sampling rate has to do with the quality of the sound vs the bit rate. All I know is that 78khz sure takes the noise out of the hearing range.
 

Well, according to Nyquist, 44kHz should be about as good to our ears as the higher rate, no?
 
Miro2424 said:
I still can't figure out what the sampling rate has to do with the quality of the sound vs the bit rate. All I know is that 78khz sure takes the noise out of the hearing range.
Click to expand...

Too few samples and you loose quality because you miss information. To few bits in the sample and you loose because you are taking low quality samples.
 
It makes sense that higher sampling makes better quality but the question is what exactly makes this sound, even though 8bit, sound better than Nintendo ?

Also the sound quality of a Karplus Strong algoritm comes from the fact that we generate the waveform from a random sample limited in range to 8bit (random numbers from 0 to 255) thus eliminating the possibility of distortion of the waveform, is that right?
 
The Amiga did 8 bit stereo sound (back when PC's beeped and that was all), it's perfectly acceptable quality.
 
Agreed, 8bit sound will give very nice sound quality!

The reason they use 16bit sound in CDs is to give a very large dynamic range, ie great quality sound with both loud and very quiet passages. If it's just loud rock guitar (or one instrument at a fixed volume) I don't think anyone could tell the difference between 8bit and 16bit sound.
 
The Amiga sound quality is easily explained, here's a quote from the Wikipedia;

"The sound chip, named Paula (Amiga) , supports four sound channels (two for the left speaker and two for the right) with 8-bit resolution for each channel and a 6-bit volume control per channel."

Thus Amiga sound comes out as a 14 bit stereo.
 

I don't think it works like that

The volume control and resolution aren't in any way connected, the sound is simply 8 bit, the volume control is no different to a simple analogue one.
 
Again from the famous Wikipedia;

" With some special programming tricks it is possible to produce 14-bit audio by combining two channels set at different volumes, giving two 14-bit channels instead of four 8-bit channels. This is done by playing the high byte of a 16 bit sample at maximum volume, and the low byte at minimum volume (both ranges overlap, so the low byte needs to be shifted right two bits)."

Thank you very much
 
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