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70 votes
Accepted

How did musicians acquire samples for tracker music (MOD, S3M, XM and the like)?

I composed a small number of Amiga tracker modules at around the turn of the 1990s, one of which even enjoyed some popularity. These songs were made, first and foremost, for my personal amusement — ...
Jukka Aho's user avatar
  • 2,062
60 votes
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Why do programmable sound generators like SID include a noise generator?

One basic distinction in acoustics is the one between sounds that oscillate with a pattern that is repeated over time and sounds that are chaotic in nature, and show no repetitive pattern. Sounds ...
Schmuddi's user avatar
  • 925
35 votes
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Why does MP3 audio decoding overwhelm retro CPU's?

What's lacking is mostly raw number-crunching ability. The MP3 format is relatively lightweight, and can be implemented using only fixed-point math (no FPU required), but it still takes a fair amount ...
Mark's user avatar
  • 8,585
32 votes

How did musicians acquire samples for tracker music (MOD, S3M, XM and the like)?

The four main ways were: you knew someone with the sampling card or sampler (many of samplers had the capability to sample sound in CD quality and save it to floppy disk). you bought some kind of &...
Martin Maly's user avatar
  • 5,575
27 votes
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How was digital sound playback achieved on the Commodore 64?

No hardware revisions are necessary. The digitization playback is achieved by bit-banging the volume register of the SID chip to simulate a digital playback device. Essentially, the SID can be used ...
Payton Byrd's user avatar
  • 1,053
23 votes

Why do programmable sound generators like SID include a noise generator?

Many PSG's (Programmable Sound Generators) at the time (such as the popular AY-3-8910) were made for applications like doorbells, kiosk machines, etc. And, of course, arcade machines and computers. ...
cbmeeks's user avatar
  • 8,531
20 votes

How did musicians acquire samples for tracker music (MOD, S3M, XM and the like)?

Did they really plug a synthesizer's audio output into a line input of a sound card and digitize the analog sound? But were audio cards of the early 90s at all capable of capturing analog audio at ...
Jean-François Fabre's user avatar
20 votes
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How was polyphony achieved on systems with only one audio channel?

I know of two ways of achieving polyphony in system with 1-bit audio systems: The simple way: time-multiplex two or more frequencies. For example, if you want the system to produce a mix of two tones,...
mcleod_ideafix's user avatar
13 votes

Why does MP3 audio decoding overwhelm retro CPU's?

Mp3 is primarily a lossy compression format for audio. It must be decompressed, and the process needs a lot of CPU time (as for retro computers.) Modern computers both have speeds good two orders of ...
SF.'s user avatar
  • 7,105
13 votes

How was polyphony achieved on systems with only one audio channel?

Just wanted to add a historical note (as this is retro computing). All Manchester computers from the earliest days generated sound by attaching a speaker to a single bit of a register (usually the ...
Manchester MUSS Alumni's user avatar
12 votes

How was polyphony achieved on systems with only one audio channel?

And these systems had not just a single audio channel, but a single-bit audio channel. There are no doubt many techniques, but a simple approach is to rapidly interleave the output of two or more ...
George Phillips's user avatar
11 votes

Why do programmable sound generators like SID include a noise generator?

In some systems, the noise channel could be used as a cheap source of pseudo-randomness, such as in the Atari POKEY (read address 0A). Here, cheap means that the CPU can do other things whilst the ...
wizzwizz4's user avatar
  • 18.6k
9 votes

How was digital sound playback achieved on the Commodore 64?

The best audio quality was obtained with pulse width modulation using the square wave voice. The oscillator was set to 0 and the pulse width was set by flipping the pulse width from 0 to maximum. ...
Stavr00's user avatar
  • 938
9 votes

Why does MP3 audio decoding overwhelm retro CPU's?

Like others already answered: old CPUs does not have enough MIPS, and/or they are lacking instructions that would helped in MP3 decoding algorithm (remember that MP3 is standardized in 1995.). Nice ...
Milan Kovac's user avatar
8 votes

Why does MP3 audio decoding overwhelm retro CPU's?

Early 68k processors implemented a multi-cycle multiply instruction (70 cycles per MULx), so the inverse MDCT would likely be the limiting factor in terms of raw CPU time.
hotpaw2's user avatar
  • 8,219
8 votes

Is it possible to use a TI-99/4A cassette cable with Digital Audio devices?

Any cassette tape system which can utilize a standard cassette tape recorder can be plugged into any audio device, with sufficient quality, and will work. You can record saved files with any audio ...
Tim Locke's user avatar
  • 4,820
6 votes
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ES688 AudioDrive 4-bit proprietary codec: Any way to decode?

With hints taken from this answer, your 4-bit ESPCM format is not that difficult to be decoded correctly. Your python decoder does a lot of things right. Out of 20 nibbles, only 19 nibbles contain ...
Michael Karcher's user avatar
6 votes

ES688 AudioDrive 4-bit proprietary codec: Any way to decode?

I also created a lot of files using ESPCM compression in the 1990s. The ones I have were saved with an extension of AUD, but internally they are .wav files. ESPCM compression takes each sample and ...
OldComputerGuy's user avatar
6 votes
Accepted

ZX Spectrum: What is the "T" state value, with reference to sound?

In the Spectrum lexicon, a t-state is just a "time state" — a single cycle of the ~3.5Mhz clock. For implied evidence of that, see e.g. this document of 128K ZX Spectrum Technical Information, which ...
Tommy's user avatar
  • 37.3k
6 votes

How was digital sound playback achieved on the Commodore 64?

There were also some more recent creative alternatives taking advantage of filters and undocumented test bits as well. Check out the Cubase64 demo by Mahoney: http://www.livet.se/mahoney/cubase64 ...
user2669489's user avatar
6 votes
Accepted

What bit depth and sampling frequency could the BBC micro play back sampled sounds?

Here's how the specific routine you posted works. It appears to be using the "4-bit linear" method mentioned on this page. The resulting samples are not truly linear, but it's easy to ...
Chromatix's user avatar
  • 16.8k
6 votes

How to wrap 32 bits drivers on 64 bits based Windows or even vxd?

The difficulty seems to be that Windows Driver Model device drivers aren't stand-alone chunks of code. They consist of two layers: the bus driver, PCI in this example, which is provided with Windows, ...
John Dallman's user avatar
  • 13.4k
5 votes

Why do programmable sound generators like SID include a noise generator?

There are many acoustic events - drum beats, steps, explosions, breath, abrasion, clicking... that are based on a lot of harmonically unrelated frequencies in relatively irregular patterns. Which is ...
rackandboneman's user avatar
5 votes

How did musicians acquire samples for tracker music (MOD, S3M, XM and the like)?

But were audio cards of the early 90s at all capable of capturing analog audio at reasonable quality? Kind of yes, but... There is relatively little "information" in audio above 10kHz, and ...
Graham's user avatar
  • 2,122
5 votes

How to write directly to the Commodore 64 (or similar) DAC

DAC is a digital analog converter. There is no such periphery on C64, but the closest to it is the SID chip, for playing sound. Also the SID chip was not designed for that. It can play ADSR (attack-...
peterh's user avatar
  • 1,779
5 votes

What bit depth and sampling frequency could the BBC micro play back sampled sounds?

The BBC Micro uses an SN76489, which provides three tone channels each with sixteen volume levels. For speech playback the standard approach is to set the channels in use to a very high frequency and ...
Tommy's user avatar
  • 37.3k
4 votes

ES688 AudioDrive 4-bit proprietary codec: Any way to decode?

While preparing a sample, I did the following: Silenced error in Python wave module (sampwidth is arbitrary - should be 0.5, but it's hardly supported): if wFormatTag == WAVE_FORMAT_PCM: try: ...
Roman Susi's user avatar
4 votes

How was digital sound playback achieved on the Commodore 64?

It seems that all the earlier posts only give partial answers to the question. The below extract of the relevant parts of my doc https://bitbucket.org/wothke/websid/src/master/docs/digi-samples.txt ...
wothke's user avatar
  • 41
3 votes

Is it possible to use a TI-99/4A cassette cable with Digital Audio devices?

I have tried to save or load from a smartphone and PC. These don't record well. However the audio file from tape may be processed on PC. Audiotap and CS1er are examples of software for the TI. I have ...
dciurchea's user avatar

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