Re: PC speaker gives incorrect results (when low and high pass filtered) and with 8088 MPH?

Posted on 2016-03-01, 22:14

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by superfury

in PC Emulation

in PC Emulation

My emulation averages up to the current rounded down samples of time, including the previous sample if it's left over. So the first block will contain 71.59 samples. Thus 71 samples are processed into a PCM sample(averaged). The next block will start with the last sample and the amount set to 0.59 …

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PIT emulation gives incorrect results with 8088 MPH's credits?

Posted on 2016-03-01, 12:55

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by superfury

in PC Emulation

in PC Emulation

It gives some kind of high sounding signal sometimes with the 1Hz high pass filter and ticking sounds (~4-6/second) without the filter. It is first generated(1.19MHz), downsampled in 60us intervals(PWM), finally skipped(downsampling it) to 44.1kHz for output. https://bitbucket.org/superfury/x86emu/ …

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Re: 8088 MPH: We Break All Your Emulators

Posted on 2016-02-29, 17:11

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by superfury

in PC Emulation

in PC Emulation

I'm curious: Is there a recording of 8088 MPH somewhere running on an actual IBM VGA graphics card instead of CGA card (so I can compare it with output by my x86EMU emulator to verify if my VGA emulation is giving the 'correct' output)?

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Re: 8086 average clocks per instruction (when running normally)?

Posted on 2016-02-27, 13:22

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by superfury

in PC Emulation

in PC Emulation

It was still there when I uploaded it. It seems to have been removed for inactivity or something like that? Unfortunately the laptop cooling ventilation I'm using this weekend seems to go wrong(it makes metallic jumping noises, like some loose metal's gotten in the fan, with little smoke coming out …

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MIDI sounds too loud?

Posted on 2016-02-25, 20:26

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by superfury

in PC Emulation

in PC Emulation

When I try to apply all volume controls with my MIDI emulation, for some reason it gets too loud, overflowing the container (according to the little noise made when playing songs). I did it according to the Soundfont 2.4 specification as far as I know. My source code: ADSR: https://bitbucket.org/ …

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Re: x86EMU emulator releases

Posted on 2016-02-24, 15:16

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by superfury

in Release Announcements

in Release Announcements

My latest build: x86EMU_20160224_1612.zip - Globalized low and high pass filters for all hardware. - Changed PC speaker low pass filter to 20kHz instead of 22kHz(22050Hz). - Improved VGA vs CPU ratio depending on available CPU speed (slower CPUs will have slower VGA, faster CPUs will have faster VGA …

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Re: How to make my sound renderer remove direct current for rendering audio?

Posted on 2016-02-23, 20:46

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by superfury

in PC Emulation

in PC Emulation

I've enabled the sound high pass filter again in the latest commit(and fixed Covox bugs). I currently still disable the low pass filter at the first post: it seems to be messing up the output, making it worse than it is(some hardware becomes very soft sound, like PC speaker and Adlib).

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Re: x86EMU emulator releases

Posted on 2016-02-23, 14:41

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by superfury

in Release Announcements

in Release Announcements

My latest build: x86EMU_20160223_1535.zip - Enabled the sound high pass filter again to protect sound output from DC (this works correctly, according to captures. The sound low pass filter is still disabled (global emulator low pass filter).). - Fixed Covox Speech Thing not clearing output when the …

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Re: x86EMU emulator releases

Posted on 2016-02-22, 18:33

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by superfury

in Release Announcements

in Release Announcements

My latest build (a little fix): x86EMU_20160222_1915.zip Removed all filters but the required MIDI low pass filter (required by the Soundfont 2.4 specification). The filters are currently messing up audio being generated (like the Adlib and even MIDI audio(high pass filter)). They will probably be …

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Re: 8086 average clocks per instruction (when running normally)?

Posted on 2016-02-22, 14:03

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by superfury

in PC Emulation

in PC Emulation

I implemented 9 cycles with 8088 (to get 8088 MPH to properly produce sound) and the original 8 cycles for the 8086. 8088MPH credits now seem to work fine, with a low LFO-like sound going through it. I tried it with 8 cycles, but 9 cycles results in better sound quality with 8088 MPH. 10 cycles …

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Re: x86EMU emulator releases

Posted on 2016-02-22, 14:01

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by superfury

in Release Announcements

in Release Announcements

My latest x86EMU build: x86EMU_20160222_1452.zip - Implemented MIDI attenuation. It will now produce more correct volume levels for it's sounds. - Fixed MIDI volume issues. - Fixex sound module issues (applies to all hardware producing sound). - Fixed 8088 clock speed to 9 cycles instead of 8 cycles …

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Re: x86EMU emulator releases

Posted on 2016-02-21, 13:14

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by superfury

in Release Announcements

in Release Announcements

My latest build: x86EMU_20160221_1330.zip - Implemented a high pass filter of 1Hz into the sound module to prevent Direct Current (DC) on the sound output. - Fixed MIDI sample overflow by clipping with too high a volume. - The SFDIMG disk image now will use a smaller, platform-independent header. …

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Re: How to make my sound renderer remove direct current for rendering audio?

Posted on 2016-02-21, 06:14

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by superfury

in PC Emulation

in PC Emulation

The wav files actually sound better(without dropouts) than the sound that's produced when running the emulator. This could be because the other hardware that's rendering constantly fills rendering buffers in the main thread, then pretty much pushes them all in one lock, push, unlock to the renderer. …

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Re: How to make my sound renderer remove direct current for rendering audio?

Posted on 2016-02-20, 19:42

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by superfury

in PC Emulation

in PC Emulation

Could it be the 'artifacts' I'm hearing isn't caused by the rendering of MIDI sound itself, but rather the music either overflowing(thus clipping) or the rendering not being in time(taking too much time to render, causing very short audio dropouts, which in turn causes the effect?) This is the …

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Re: How to make my sound renderer remove direct current for rendering audio?

Posted on 2016-02-20, 16:32

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by superfury

in PC Emulation

in PC Emulation

I've made two captures. The first captures the output without the sound module filtering it(high and low pass filters disabled). The second capture also has the MIDI module low pass filter disabled. recording_with-without-MIDI-lowpass.zip Edit: When I open the Soundfont in Viena (from the Synthfont …

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Re: x86EMU emulator releases

Posted on 2016-02-20, 15:06

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by superfury

in Release Announcements

in Release Announcements

All system specific stuff is in the header file concerning the system (types_win.h, types_linux.h, types_psp.h). All other defines and functions are either in the normal code itself (and in it's respective header file) or defined in it's system specific header (like the mkdir being mapped to …

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Re: How to make my sound renderer remove direct current for rendering audio?

Posted on 2016-02-20, 14:27

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by superfury

in PC Emulation

in PC Emulation

This is a Flute (instrument #74) playing a high tone (tone 0x60) at default volume (0x40): recording_6.zip I must admit it sounds worse within the emulator itself, as it suffers from lag in the rendering function waiting for the main thread (semaphores waiting for access). I must admit that the song …

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Re: How to make my sound renderer remove direct current for rendering audio?

Posted on 2016-02-19, 23:40

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by superfury

in PC Emulation

in PC Emulation

I could write a simple TP6/C program that instructs the PIT to generate a frequency and wait infinitely. Although the output will have gaps that way(the PC Speaker buffer is not filling fast enough for maintaining the tone) unless I decrease the CPU speed far below 8086 speed to give it more time to …

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Re: How to make my sound renderer remove direct current for rendering audio?

Posted on 2016-02-19, 23:00

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by superfury

in PC Emulation

in PC Emulation

I don't know that. I do know that the MIDI clips it's samples after applying the volume to prevent overflow(so does the adlib, but it mixes it's own channels and then clips to 16-bit itself, before sending it's output to the sound module. The MIDI handles it's channels seperately, because they have …

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Re: 8086 average clocks per instruction (when running normally)?

Posted on 2016-02-19, 22:38

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by superfury

in PC Emulation

in PC Emulation

That .wav file would come in handy for comparing with the output of my emulator. It might be giving 'correct' output with 8088 MPH after all (Recording emulated output is also possible using it's sound menu option in the BIOS settings menu)? It's giving about correct results with the new Default …

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