"music" in Xenon meteors noise

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Symoon
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"music" in Xenon meteors noise

Post by Symoon » Thu Jun 23, 2011 5:25 pm

This is a very old story.
When I was young, playing Xenon 1, I kept telling my brothers that in the meteors noise (level 3), I was hearing lost in the noise a small music, like bells. They claimed they didn't hear anything.
The music consists of 4 notes repeating about every 3 seconds.

Years later I wondered if I was crazy and recorded it, I can still hear them (although one of my ears seems to have suffered from ACDC shows ;-).
Can you hear them ?
http://mercenarysite.free.fr/oric/xenon ... oteurs.wav

If you can't, here's the same sample, hyper-filtered with noise reduction and other ones, so you can hear more or less what the notes are:
http://mercenarysite.free.fr/oric/xenon ... iltres.wav

Now I'm wondering how these notes are there... Never really dug the subject further, not sure if this is specific to Xenon or the the Oric white noise generation.

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Post by Twilighte » Fri Jun 24, 2011 10:43 pm

I didn't hear bells with the first sample but there is a clear repetition of the noise algorythm which i guess you will always get with the AY.

Its very interesting since this may be useful in reproducing a much more accurate white noise generator in the emulators, or perhaps this is already done?

The second wav was wonderful. Emphasising the repetition perfectly.
It still amazes me that such a simple chip as the AY was able to produce complex tones and noises just using the hardware.

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Re: "music" in Xenon meteors noise

Post by Xeron » Sat Jun 25, 2011 10:45 am

I can't hear the bells at all in the first sample.

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Post by JamesD » Sat Jun 25, 2011 4:59 pm

Not hearing bells in the first one.

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Post by Symoon » Sat Jun 25, 2011 11:59 pm

Thanks to all for the replies. Wow, do I have bionic ears? :shock: :wink:

Another (and last) test: I copied the higher "bell" from the meteors sample (IMO the easiest to hear), didn't do any signal modification, and simply pasted it 4 times in the following (short) WAV file.
http://mercenarysite.free.fr/oric/xenon ... eurs_3.wav

This time you should hear "tik tik tik tik" exactly 4 times behind the white noise, just like someone hammering on an anvil or something like that.
This way you might hear how it sounds like and hear it more easily in the very first file.

I suggest using headphones, I'm hearing them much easier this way.

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Post by JamesD » Sun Jun 26, 2011 9:30 pm

I definitely hear the tik tik tik tik

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Post by JamesD » Sun Jun 26, 2011 9:33 pm

BTW, I hear an occasional soft click in the first one but no ringing.

Your ears/brain must be picking up some sort of harmonic frequencies

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Post by Twilighte » Wed Jun 29, 2011 5:56 pm

Since being diagnosed with Crappy ear syndrome my quality of hearing has gone to pot. Now what were you saying?

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Windows 2000 music

Post by barnsey123 » Thu Jun 30, 2011 2:31 pm

Can't here the bells but then I've got Tinnitus in both lugholes.
On this subject though, for years I've said to people that one of the Windows startup jingles contains the sound of a woman in the throws of orgasm. Listen to the windows 2000 jingle http://www.youtube.com/watch?v=BFkry3zzutI
It gets a bit gaspy at the end. Tinnitus or not it's deffo there!

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Post by Godzil » Thu Jun 30, 2011 3:47 pm

I can hear something too, but not the same thing as what Symoon describe ;)

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Post by Chema » Thu Jun 30, 2011 5:38 pm

I can't hear the tik tik... but I'll check with headphones or something... Anyway my ear is not as good as it should be :(

I think you are hearing a repetition in the white noise generation of the AY... or maybe some "hidden" message for those with bionic ears :shock:

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Post by kenneth » Thu Jun 30, 2011 7:17 pm

Perhaps a sound signature of the inventor of the AY?
Some instructions not listed in the 6502 runs correctly, the engineers hide us something...

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Post by Godzil » Fri Jul 01, 2011 10:19 am

kenneth wrote:Perhaps a sound signature of the inventor of the AY?
Some instructions not listed in the 6502 runs correctly, the engineers hide us something...
In fact, it seems related to the way random number are generated. The noise generator is mainly a random function, and since on computer random is never really random, especially on old components, the tictic we ear can be due to some repetitions in the random sequence.

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Re: "music" in Xenon meteors noise

Post by telbee » Sat Jul 02, 2011 10:20 pm

Symoon wrote:This is a very old story.
When I was young, playing Xenon 1, I kept telling my brothers that in the meteors noise (level 3), I was hearing lost in the noise a small music, like bells. They claimed they didn't hear anything.
The music consists of 4 notes repeating about every 3 seconds.

Years later I wondered if I was crazy and recorded it, I can still hear them (although one of my ears seems to have suffered from ACDC shows ;-).
Can you hear them ?
http://mercenarysite.free.fr/oric/xenon ... oteurs.wav

If you can't, here's the same sample, hyper-filtered with noise reduction and other ones, so you can hear more or less what the notes are:
http://mercenarysite.free.fr/oric/xenon ... iltres.wav


I can just about hear the 'tick tick' thing. Doesn't sound like bells though...
Funnily enough though, I was deaf for 2 days after seeing AC/DC in Dublin and have suffered TInnitus ever since!! :) Kids - use those earplugs lol... :) T

Now I'm wondering how these notes are there... Never really dug the subject further, not sure if this is specific to Xenon or the the Oric white noise generation.

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Re:

Post by ThomH » Thu Jan 05, 2017 11:10 pm

Godzil wrote:
kenneth wrote:Perhaps a sound signature of the inventor of the AY?
Some instructions not listed in the 6502 runs correctly, the engineers hide us something...
In fact, it seems related to the way random number are generated. The noise generator is mainly a random function, and since on computer random is never really random, especially on old components, the tictic we ear can be due to some repetitions in the random sequence.
A million years late, as ever, but the random noise generator function for the AY is known — see e.g. this Amstrad CPC wiki.

To reproduce the formulation here just in case other sources drop offline, it's a 16-bit shift register. It shifts at the noise frequency. Upon each shift:
  • output is XORd with the bit that just fell off the bottom;
  • the new top bit is the bit that fell off XORd with the bit that just moved from bit 3 to bit 2.
I'm confident the same solution is given independently in this Russian documentation based on the included Pascal code — actually x86 assembly inline in Pascal code — and Google's translated version of the included document, except that they conceptualised the shift register as going to the left instead of the right so talk about bit 13 rather than bit 2.

That's how I implemented it on my emulator and it feels correct. So I'm confident based on (i) subjective listening; and (ii) two almost-certainly independent sources.

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