Musical potential of the NEXT.

This section is for discussing everything about Next hardware and latest updates.
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KyotoG
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Re: Musical potential of the NEXT.

Post by KyotoG » Tue Oct 03, 2017 12:39 am

"The SID only allows one to chose from 4 fixed waveforms: square wave (the same as the AY), triangle wave, saw-tooth wave, and noise."

This is not quite correct. The SID has a pulse wave, with a variable duty cycle (which can be a square wave if set to 50%). The waveforms can also be combined, which ORs the selected waveforms together.

I'm working on an editor and player that runs directly on the Next, and inspired by Cubase. It's very much a work on progress but have posted here (viewtopic.php?f=17&t=764) for anyone who would like to keep tabs on the work.

SamusDrake
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Re: Musical potential of the NEXT.

Post by SamusDrake » Tue Oct 03, 2017 7:36 pm

KyotoG, that sounds great! The interface looks easy to use, too. ^_^

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Re: Musical potential of the NEXT.

Post by SamusDrake » Tue Oct 03, 2017 11:19 pm

Just thought I would ask this question while the iron is still hot...

I'm able to create a single beep sound for the 48K in Basic and Assembly, but I've heard many 48K tunes where it sounds like two notes being played simultaneously. Just curious how that is done, and how to go about doing that - in either basic or assembly.

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varmfskii
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Re: Musical potential of the NEXT.

Post by varmfskii » Tue Oct 03, 2017 11:56 pm

Spectrum 48k audio is 1-bit, but by varying the duty cycle of the transitions quickly enough you can take advantage of capactiance and intertia to create multiple levels with that you can simulate mixing multiple tones. For BASIC, forget it, it isn't fast enough. In assembly it is a matter of precalculation, then twiddling the bits fast enough.
Backer #2741 - TS2068, Byte, ZX Evolution

SamusDrake
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Re: Musical potential of the NEXT.

Post by SamusDrake » Wed Oct 04, 2017 7:17 am

I see, so thats why 48K music seemed to play during title or menu screens, and not the game itself as that technique was cpu intensive.

Cheers, Varmfskii. ^_^

Alcoholics Anonymous
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Re: Musical potential of the NEXT.

Post by Alcoholics Anonymous » Thu Oct 05, 2017 8:06 pm

utz is on this forum and he's one of the 1-bit wizards, having written at least a dozen 1-bit sound engines with different qualities.

viewtopic.php?f=17&t=778&p=5261#p5261
http://randomflux.info/1bit/

The other common 1-bit music composer is beepola.

PiyoTaro
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Re: Musical potential of the NEXT.

Post by PiyoTaro » Sat Oct 07, 2017 5:23 am

In the machine spec at the kickstarter "FM sound" is written. However, TURBOSOUND-NEXT adopted SID 6581 instead of Yamaha FM sound chip.
Audio: 3x AY-3-8912 audio chips with stereo output + FM sound
If "FM sound" is Yamaha's FM sound chip and it is simulated with FPGA, which chip is adopted?
PiyoTaro wrote:
Mon Oct 02, 2017 9:08 am
2.
In the past, I have posted on "What chips are adopted for FM tone generator chip?"
In "TURBOSOUND-FM"(and Masakrator FM?), two OPN (YM2203) are adopted instead of AY. So I imagined a sound chip of Sega megadrive.

I think that it is up to implementing the new function on the emulator and then making it into FPGA.
I want the emulator to have a simulation DLL for the tone generator chip of OPM (YM2151) or OPN (YM2203, YM3438, YM2608).

Additional notes
Mr.Yuzo Koshiro is famous as a musician who makes game music with FM sound chip.
‘Etrian_Odyssey_Battle_Theme_2 (OPN,OPNA)’ by Yuzo_Koshiro(Retro_Style) on #SoundCloud? #np https://soundcloud.com/yuzo_koshiro/etr ... soundcloud
‘Flash_Flash_Flash (OPNA)’ by Yuzo_Koshiro(Retro_Style) on #SoundCloud? #np https://soundcloud.com/yuzo_koshiro/fla ... soundcloud

Sweeney
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Re: Musical potential of the NEXT.

Post by Sweeney » Sat Oct 07, 2017 11:16 am

I’m not sure you get how FPGAs work. There are no DLLs. Each sound chip simulation is implemented as a section of logic on the FPGA and is independent of the others. The current NEXT design has implemented three AY-3-8912 chips, plus a single 6581. They may have planned to place an FM sound chip in the design, but none of the two sound chip designs are true FM.
Once the source code for the NEXT is made available it should be possible to remove one or more of the above chips from the design and drop in a true FM chip (the YMF262 is available as Verilog source for example).

PiyoTaro
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Re: Musical potential of the NEXT.

Post by PiyoTaro » Mon Nov 27, 2017 5:22 pm

Copper processor seems to be a concept used in Amiga.
mdf200 wrote:
Fri Nov 24, 2017 8:40 am
at thread "Next features list"

Copper docs..... https://docs.google.com/document/d/1nhB ... sp=sharing
I understand that it is a processor that can scanline-interrupts finely, assuming 312 scanlines on the TV screen updated at 50 Hz. A PCM tone generator with 15600 Hz can be realized only by software.

I found the specification "Soundrive 1.05 amalgamates these standards into four 8-bit" at the place I do not know ("Z88dk").
Does the SpectrumNext BIOS have a music driver that can play *.MOD format sequences ? I think :D .


As below, I have said that not only this thread but also other threads, I want audio codec hardware that PCM can play without using programming techniques such as scan line interrupts.
PiyoTaro wrote:
Mon Oct 02, 2017 4:52 pm
varmfskii wrote:
Mon Oct 02, 2017 4:16 pm
PiyoTaro
Depends on the game. I suspect that most audio in games will be done using the sound chips. It is easier, portrays the classic 8-bit sound, and doesn't consume that much of the CPU. If the dma can be set up for a specific rate, it could handle the audio, if not it isn't helpful for this particular job. The hardest thing is not shoving the data, but rather the timing. If you are using the d/a audio, you want to send a value every 2-4 scan lines. For this you can either count cycles (great for demos or pure audio, not so much for most applications in games) or handle an interrupt every few lines (inefficient).
Indeed, if we consider the PSG tone generator chip to be a "4-bit DAC", I think that it is possible to reproduce 2 seconds with the sound quality of "4 bits 32 KHz" with the 8 KB data of the MMU 1 bank.
By the way, "SpectrumNext" also has "8 bit DAC" output. For background playback of PCM sound, there is a demonstration that places a buffer on the Z80 address bus and plays it with DMA.
I think that it is not suitable for "the new hardware that will appear in the future" how to use the scan line interrupt frequently.

By the way, I am thinking of PCM sound to sound a short time tone of "gate snare drum" and "orchestra hit", a long time tone such as cymbal and explosion sound. How about the sound quality?

PiyoTaro
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Re: Musical potential of the NEXT.

Post by PiyoTaro » Mon Apr 30, 2018 9:38 am

Why did I take "YM 2151" as an example? That's because I saw a post in the fall of 2016 that completed the FM tone generator core on ZX-A in the "ZX-Uno" forum. It said that it was developed from "YM 2203" and it was released, but it seems that the project posted on OpenCores.org is only YM 2151 project.
In the posting, there is a description that implements it in Atari ST and is attempting to play data in MDX format (Data format of music driver for Japanese X68000) and that it is producing the "YM 3812" core.

I was hoping he would complete the YM 2203 tone generator core and release it on this forum to realize the sound core for "Turbosound FM for SpectrumNext" and the arcade game "Ghosts' n Goblins".

---
20180516 Additional notes:
I wrote about jotego's JT51 core. He also said JT03 that reproduced YM2203.
In his blog "Retronica" there was also written about the YM2151, electrical tests and the hardware used in Japan.
---
20180714
There was his interview article on the game information site.:
RetroManiac May 5, 2017
"Creo que acabaré diseñando una placa FPGA orientada a sistemas arcade". Hablamos con Jose Tejada, autor de cores de chips Yamaha para FPGA http://www.retromaniac.es/2017/05/creo- ... placa.html
Last edited by PiyoTaro on Sat Jul 14, 2018 2:23 pm, edited 2 times in total.

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