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Comment by S_A_P | Hacker News Reader

I’ve owned a few 808s and sampled all of them. They were indeed all different sounding. The cowbells are one exception and sounded more like the 2 Live Crew example. Most of the variation was in the hi hat and cymbals. Which IIRC is 6 square waves and a noise source.

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Very interesting! Thank you! I did a little looking and found this FWIW...

I noticed in OP's post that the two frequencies for the cowbell are 540hz and 800hz (although I don't see where this is denoted on the original schematics.) But we'll assume they're accurate numbers.

While a perfect fifth is a difference of 7 semitones, this produces a difference of only 6.804 semitones. It would seem that its designers didn't have a perfect fifth in mind.

Also, 540Hz is C#5 -45 cents and 800Hz is G5 +35 cents. So neither note seems intended to correspond to any natural key.

One of the diagrams shows the frequencies as 1.85ms and 1.25ms, 540.5 and 800 Hz respectively.

In the original circuit,the same RC network is used for both the attack and decay so that circuit will indeed produce a 1:1 mark:space ratio.

Curious about the term "1:1 mark:space ratio" since it was also in the article. I would have used the term "50% duty cycle".

I purposely repeated the OP's wording but since we're talking about an astable multivibrator,frequency and duty cycle (in percent) makes sense. I did a lot of circuit design for communications systems and I associate the words mark and space with ones and zeroes in a frame/word.

I wondered if it was an English (not American) phrasing.

More on the origins of the terminology here: https://en.wikipedia.org/wiki/Mark_and_space

> While a perfect fifth is a difference of 7 semitones, this produces a difference of only 6.804 semitones. It would seem that its designers didn't have a perfect fifth in mind.

Remember that 7 semitones is not a perfect fifth. (Note this depends on your definition of perfect fifth, some people allow for being close, since equal temperament is so common.)

While a perfect fifth is a 3:2 ratio of frequency, seven semitones isn’t exactly 1.5, it’s more like 1.498.

800/540 is ~ 1.48, so I definitely agree the designers weren’t going for a fifth, very likely they wanted some beat interference to give it a nice metallic warble.

You are correct sir.

I was speaking (a bit erroneously) in the context of an equal tempered scale. (I think.)

Indeed, the natural overtone series is the proper context for a true perfect fifth.

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