VOGONS


First post, by SaxxonPike

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Greetings all,

I'm working on a blog post with the aim of providing solutions that work around MPU-401 bugs in the SB16 while still being able to use the other functionality of the SB16 itself. I still like being able to have a real SB16 in my system - more or less because some music production software I like to stream with such as FastTracker and Impulse Tracker are tailored to the 44.1khz stereo output.

With some cards, there are onboard jumpers that allow you to explicitly disable the MPU (the MPUEN jumper) so that you can use a different device. But others lack this jumper, and even others still use PnP which require special configuration. I'm not all that familiar with these cards.

For the sake of further filling out information in this article, how much do you know about configuring the MPU-401 functionality specifically on affected cards, and what workarounds have you found? What are other Vogons threads you recommend citing for this information? Ideally, I'd like to get some of these ideas in the same place.

My current card of choice is a CT2260 and I'm using the MPU-401 interface built into the Via 686B southbridge. But I'm sure there are a lot of other creative solutions out there 😀

This is what I have so far: https://ilovepa.ws/working-around-sound-blast … 6-mpu-401-bugs/

Sound device guides:
Sound Blaster
Aztech
OPL3-SA

Reply 1 of 5, by gerwin

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I wrote something down here, but it is about workarounds on the driver's side. One being an interrupt tweak, another is increasing the DMA buffer.
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Reply 2 of 5, by Gmlb256

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I don't have any SB16-based sound card affected by the hanging note bug but I'm aware that there is a workaround written by NewRisingSun: FixMPU: Software solution for "hanging note bug" on SB16 with DSP >v4.06 <v4.16

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Reply 3 of 5, by GL1zdA

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On Windows 9x with PnP or pseudo-PnP Sound Blaster cards, it should be enough to change the port in the Device Manager. The Creative drivers will sync these settings with the BLASTER variable and initialize the card accordingly in DOS mode. From there I take a route similar to yours, I use a different card for MPU-401, in one of my builds a Vibra 16S integrated on the motherboard works peacefully with a Turtle Beach Maui.

I'm not 100% sure, but disabling the MPU-401 on a Sound Blaster might also disable the ability to use the AWE32 EMU8000 via MPU-401 in the Windows's DOS box, so personally I just set it to 0x300, since this port can often be configured for the MPU-401 in games. I can check later this month what happens if I disable the MPU-401 on the SB16 part altogether.

If you're adventurous, you might check the SB16 WDM drivers taken from Windows ME to 98. This might also work, since the MPU-401 is routed by the drivers to the device you select in the Multimedia control panel.

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Reply 4 of 5, by SaxxonPike

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Gmlb256 wrote on 2023-07-31, 20:32:

I don't have any SB16-based sound card affected by the hanging note bug but I'm aware that there is a workaround written by NewRisingSun: FixMPU: Software solution for "hanging note bug" on SB16 with DSP >v4.06 <v4.16

Thanks for this! I've been cooking up a music related project myself and I think incorporating that technique into my own player will be really worthwhile.

GL1zdA wrote on 2023-07-31, 20:55:

On Windows 9x with PnP or pseudo-PnP Sound Blaster cards, it should be enough to change the port in the Device Manager. The Creative drivers will sync these settings with the BLASTER variable and initialize the card accordingly in DOS mode. From there I take a route similar to yours, I use a different card for MPU-401, in one of my builds a Vibra 16S integrated on the motherboard works peacefully with a Turtle Beach Maui.

I'm not 100% sure, but disabling the MPU-401 on a Sound Blaster might also disable the ability to use the AWE32 EMU8000 via MPU-401 in the Windows's DOS box, so personally I just set it to 0x300, since this port can often be configured for the MPU-401 in games. I can check later this month what happens if I disable the MPU-401 on the SB16 part altogether.

If you're adventurous, you might check the SB16 WDM drivers taken from Windows ME to 98. This might also work, since the MPU-401 is routed by the drivers to the device you select in the Multimedia control panel.

This is useful information, thanks. I haven't had an AWE32 or 64 for a while now, so I'd really like to know what the effect of this is. I imagine there has to be a good reason they had made the distinction between MPUEN and MFBEN.

Sound device guides:
Sound Blaster
Aztech
OPL3-SA

Reply 5 of 5, by Tiido

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MFBEN is for connecting emulation IRQ to NMI of the motherboard so that TSR can emulate MIDI stuff when the card hardware gets any MPU401 accesses.

But as far as the cards go, you can put the MPU to another address. UNISOUND should work with most/all the PnP SB varieties that lack the jumpers, and can do that for you with more convenience than Creative's own drivers.

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