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ivop

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Posts posted by ivop

  1. Posted

    That's not what I asked. A# major is obviously quite in tune with these tables. Only the tonic is a bit off.

     

    Now transpose this to E♭ major. It WILL be out of tune.

     

    BTW nobody disagrees on this. It's the law of nature. 12-TET is a compromise. Vinscool's table is another compromise, but closer to just intonation in certain keys. (keys as is musical keys, not piano keys).

     

    Also note that A=440Hz is arbitrary. Vinscool uses 443.9Hz. Philharmonic orchestras around the world use, and have used, widely varying tunings.

     

    https://en.wikipedia.org/wiki/Concert_pitch

     

    As low as 415Hz, as high as 470Hz.

     

     

    • Like 2

  3. Posted

    8 hours ago, emkay said:

    The point is the 220 440 880 Hz correctness. And this seems correct enough even in the 8 bit resolution.

    The 432 Hz calculation is just wrong at this point. Always was , and I have been told "it's good" ;)

    Synth tunes were always based on 440Hz calculations. 

    Yeah, but that's 12-TET. We're talking just intonation here. If you base that on A=220,440,880,... songs in the key of C Major/A Minor, and some other keys will sound better. But try a tune in A# or G#m, and it will be all over the place and sound horribly out of tune.

     

    Experiment: just for fun, transpose your whole song one semitone up or down and run it through RMT2LZSS with Vinscools tables.

    • Like 1

  4. Posted · Edited by ivop

    1 hour ago, emkay said:

    Since VinsCool did that nice notation correction, a lot tunes make just sense. 

    If they are in a key that is compatible with VinsCool's intonation ;) And this song turned out nicely!

     

    Somewhere on my todo-list it says create a spreadheet to generate a just inonated major scale in each of the twelve keys. Like how they tuned (forte)pianos back in the day. Before 12-TET ruined it all ;)

     

    Also, run all distortion C notes through aubiopitch to know the exact frequency. Based on that, each of the twelve musical keys could be intonated to each of the seven notes per octave.

     

    Like how Vinscool based Am/C/Dm etc... on A=443.9hz, in unison with the distortion C basses for these specific keys, and their chords. That could be extended to each of the twelve major/minor scales.

     

    • Thanks 1

  5. Posted

    1 minute ago, emkay said:

    Different tastes and different meanings. I personally like it a lot. I really could imagine a puzzling game listening to it on and on.

    You might have misunderstood me. When I said "One of your better feats!" , that was a compliment. I could listen to this several times, too.

    • Like 3

  6. Posted

    One of your better feats! It sounds open, not the choked PWM sounds and/or chock-full of out-of-tune blips and bleeps.

     

    As for the "orbits" as you call them, you can sometimes use a single frame of the bass with the harsh sound, but transposed. The harsh and soft sound are an octave apart. But that simulates slap bass, and sounds cool ;)

    • Like 2

  7. Posted

    The power supply has an effect on the color. The Color Adjustment circuit is driven by phase1 of the CPU, a ±5V signal. After that, it is run through a charge pump to create ±10V, which goes through a potmeter, which eventually creates the voltage that GTIA sees. Check those color pots. After all these years, they might need a good turning back and forth, and then leave them at the right spot. It's all analog.

    • Like 2

  11. Posted · Edited by ivop

    2 hours ago, emkay said:

    OK. 

    Rensoup mentioned earlier that he does "streaming" there. No recognition of repeated patterns. 

    Possibly things changed?

    The streams rensoup is streaming to Pokey are compressed by the LZSS algorithm, which is part of the Lempel-Ziv family of data compression algorithms. They either build a dictionary of multi byte words (like LZW does), or use back references within a certain window pointing back in the stream. These back references are found by pattern matching.

     

    I think you mean patterns at the RMT level. If they are within the LZSS back reference window, they are compressed. But with long songs, they could be too far apart. Then indeed, it could be beneficial to compress just each RMT pattern. But then your player needs the RMT song data to know when to play which pattern.

    • Like 2

  16. Posted · Edited by ivop

    On 4/5/2021 at 7:27 PM, ivop said:

    but I also did something extremely stupid. I overwrote my only copy of the bus proposal .ods file with an empty sheet :(

    Turned out it was not a PEBKAC after all. I almost ran out of space on my home filesystem. Luckily I noticed because KiCad mentioned I was low on diskspace. Just for fun I tried LibreOffice Calc again. Saved a sheet. Added some values, saved again, and lo and behold, corruption! Unrecoverable by "repair" or whatever they call it. A proper program never overwrites the original. It writes a new file, and only if that was succesfull, it moves it to the old file. Or even better, renames the old file to .bak, and renames the old file to the new file.

     

    Anyway, I moved 12GB to another partition, and it's all fine now. Recreated the bus design in Calc. Now moving on to the power supply part of the backplane.

  18. Posted

    If the external U1MB will be a CART/ECI board, it should be plug and play after removing the MMU, RAM and ROM from the backplane. Hopefully it will also do the 64kB base RAM, otherwise it would still need a separate 64kB RAM card.

  19. Posted

    2 hours ago, Levas said:

    My design is 2 layers only :) , €26.58 for 5 boards.  If it was 4 layers... I never would order it.

    👍 It's nice to see an SMD version of the 1088XEL. And that's a good price! With SMD there's less need for full power and ground planes.

     

    My goal is not make it smaller, but larger and make it easy to understand. All through-hole, and an oldskool backplane. The cards will all be 2 layers, 1.6mm, 1oz copper, but I consider doing the backplane at 2mm, 4 layers, 2oz copper and 1oz for the sandwiched layers. If that's not too expensive ;)

  20. Posted

    2 hours ago, ZuluGula said:

    Is it going to be possible to install U1MB?

    Sure, that should be possible. Either by connecting to the MMU and ROM card, or a dedicated carrier board could be created, and then remove the MMU card (or chip if it's on the same board as the PIA), and the ROM and extended RAM cards. It would need a 64kB base RAM card though.

     

  21. Posted · Edited by ivop
    added the key of C to most tunes...

    37 minutes ago, VinsCool said:

    Not really sure anymore honestly.

    Truth to be told, a lot of that stuff doesn't totally make sense to me.

    I'm working on an essay about sizecoding of music, and it starts with an introduction to music in general. Major scales, building chords, minor chords, seventh and major seventh chords. But I have to draw the line somewhere to not become too technical. Add9, Add11, Sus2, etc... and other scales and tuning is under "Further Reading" :D

     

    Quote

    The main intervals I relied on there were octaves, fifths and a handful of random notes that were adjusted inbetween to fit with as many notes as possible there.

     

    A and D were the main notes that were referenced there as well.

    Sharps are the ones that were annoying to get properly, and aren't 100% good, but in most cases things seem to work okay with what I got currently :)

    This explains a lot. Most tunes are either in C, D, E, G, or A. Chiptunes mostly A and D. If you take D as your root note, A is the fifth. In the major scale.

     

    Here's a wikipedia page on Just Intonation: https://en.wikipedia.org/wiki/Just_intonation Especially the Diatonic Scale is interesting.

     

    Note that if I would send you an RMT that's in the key of A#, it would suck with your new tables ;) But you can always transpose!!

  22. Posted

    On 3/31/2021 at 4:12 AM, VinsCool said:

    Well considering I did all my tuning based on intervals, this is indeed true lol

    Which intervals did you use exactly? Once you leave 12-TET, your tuning will improve in certain keys, but decrease in other keys. To which key and base note did you tune your chromatic scales?

     

  25. Posted

    For now, I leave the 1090 slots of the board, but that's certainly something that could be added later at the left or right side. Depending on the amount of slots I need, the current board might be extended to 30.5 × 24.4 cm, which is ATX. But to keep the cost manageable, I'll stick to 20x20 for now. You can also daisy chain multiple boards by soldering pinheaders at the sides and use a flatcable.

     

    Cards I will be making first are:

     

    1. GTIA + basic composite video out

    2. ANTIC

    3. CPU

     

    The test clocks and scope out the address and databus. After that,

     

    4. MMU

    5. PIA

     

    Test this, with SysCheck for RAM and ROM

     

    6. POKEY, stereo, plus audio mixer

    7. ROM

    8. RAM

     

    Test, and finished ;)

     

    Then a SIO card with an SDrive, a SIO card with MIDI, and a SIO to normal SIO connecter converter.

     

    Long way to go.

     

    • Like 4
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