Yamaha YMF71x SB Pro Mixer Bug Issue Fix

[squareguy]

Thanks for all your work on this. This might be the perfect card for me once I fully mod it. I'm going to order a few 719's since I 'want' the newest.

I am curious though. Do we know for sure if the audio channels are reversed? Are only parts of it reversed? Hopefully if it is reversed it's everything and not just certain parts.

[Jolaes76]

Great work all in all, amending the card's all curable deficiencies.
Of course, one still needs to keep a real sb pro around to cover all shareware game bases, adpcm issues
until a perfect sb pro clone is born from scratch - which I think will never happen.

[PhilsComputerLab]

I am curious though. Do we know for sure if the audio channels are reversed? Are only parts of it reversed? Hopefully if it is reversed it's everything and not just certain parts.

Someone tested this if I remember correctly. AFAIK everything is reversed, so just swap the audio cables around

[James-F]

Actually, don't swap the cables around.

The mixer works the right way, meaning in Wolfenstein 3D the stereo is correct, or simply lowering the Left channel to zero results in sound only from the Right channel.
It is only the High-Speed DMA mode which is the Stereo mode of the SBPro is reversed, just like it was on the real SBPro.
I believe most games that use the SBPro Stereo mode already taken this abnormality into account.

In Duke Nukem 3D setup the Stereo will be automatically reversed if you select the SBPro and you don't need to enable "Reverse Stereo" switch.
This can be tested in DOSBox, where the SBPro Stereo mode is NOT reversed like the real hardware.

[PhilsComputerLab]

Well but you got to swap it for your FM Stereo and Wavetable, right? Man I really got to test this properly one day...

[James-F]

I've tested this now.
Assuming the channels are correct in the mixer:

YMF71x:
FM = Correct.
Wavetable = Reversed (see further down the page for a fix).
SBPro = Correct.
Mixer = Correct.

DOSBox:
FM = Correct.
SBPro = Reversed.
Mixer = Correct.

I've tried Duke3D and Tie Fighter where the stereo already compensated for the real SBPro, but I had to switch "Reverse Stereo" in DOSBox.
Descent is not compensated, I had to reverse to sound correct with the YMF.

EDIT:
New info about the SBPro stereo "issue":
https://www.vogons.org/viewtopic.php?f=46&t=50539

[Scali]

I never got this whole 'reverse stereo' thing... I got an SB Pro 2.0 when they were brand new, and I never had to use the 'reverse stereo' option in any games, nor did I ever suffer from the channels being reversed in any software.
Does it only happen on some SB Pro cards? Or is it related to the rest of the system somehow? That it happens with some motherboards/chipsets/CPUs/whatever, but not with others?

[James-F]

I got an SB Pro 2.0 when they were brand new, and I never had to use the 'reverse stereo' option in any games,

If I think about it, there is nothing wrong with the SBPro Stereo sound at all.
Most games that designed for SBPro Stereo mode simply play correctly WITHOUT having to engage the Reverse switch.
Where the notion that the SBPro Stereo is reversed came from, beats me...

Can someone please test Duke Nukem 3D SETUP with a real CT1600 SBPro2.0 if it is reversed or not with the Reverse switch turned OFF.

[squareguy]

I'll dig out my CT1600 and report back

[Bancho]

Just wanted to chime in and say what an awesome thread. Using the info in this thread i set up my YMF719/YMF704C card to sound really good, primarily eliminating the bit of noise i was experiencing. I was also originally using the speaker-out where the noise was coming from, switched to line out and it sounds so much better now. My card doesn't seem to have any jumpers on for SPK/LINE.

Really need to test some games on it now, the only game i've been testing was Doom and Doom2. They 719/704C should be a really great combo.

[James-F]

DOOM plays Stereo correctly with YMF71x.
DOSBox with sbtype=sbpro2, is reversed and there is not way to change it.

Run the following command line:

Code: Select all

SET DMXOPTION=-opl3-phase
Doom.exe

-opl3 will enable opl3 sound in Doom, (edit: works in Windows but not DOS).
-phase will enable full Stereo mode, without it the stereo effect is weak.

[squareguy]

Seems I can only find shareware version of Duke and it doesn't have sound check. I'll have to dig up my Duke CD....

[squareguy]

OK

Duke 3D 1.4 Atomic under sound test with real CT1600 and SBPro 2.0 selected in setup and reverse not checked the sound test plays left and right correctly

[jesolo]

I never got this whole 'reverse stereo' thing... I got an SB Pro 2.0 when they were brand new, and I never had to use the 'reverse stereo' option in any games, nor did I ever suffer from the channels being reversed in any software.
Does it only happen on some SB Pro cards? Or is it related to the rest of the system somehow? That it happens with some motherboards/chipsets/CPUs/whatever, but not with others?

My understanding is that this reverse stereo "bug" was present in the original Creative Labs Sound Blaster Pro, but was fixed in the Creative Labs Sound Blaster Pro II models.
However, I've come across some Sound Blaster Pro II compatible cards that exhibit the reverse stereo effect, namely the Sound Galaxy NX Pro (FCC ID: I38-SGNXPRO) and the Sound Galaxy Pro16L/Extra (FCC ID: I38-MMSN812 - mine is actually the OEM model Reveal SC400 Rev.2).

I have no idea why these two cards would exhibit this behaviour, because my Sound Galaxy Basic 16 (I38-MMSN810), which uses the same chipset as the Sound Galaxy NX Pro, does not exhibit the reverse stereo effect.
This happens in games like Star Wars X-Wing and even in demos like Future Crew's Panic (you can clearly hear it in the intro sequence).

[firage]

I never got this whole 'reverse stereo' thing... I got an SB Pro 2.0 when they were brand new, and I never had to use the 'reverse stereo' option in any games, nor did I ever suffer from the channels being reversed in any software.
Does it only happen on some SB Pro cards? Or is it related to the rest of the system somehow? That it happens with some motherboards/chipsets/CPUs/whatever, but not with others?

My understanding is that this reverse stereo "bug" was present in the original Creative Labs Sound Blaster Pro, but was fixed in the Creative Labs Sound Blaster Pro II models.
However, I've come across some Sound Blaster Pro II compatible cards that exhibit the reverse stereo effect, namely the Sound Galaxy NX Pro (FCC ID: I38-SGNXPRO) and the Sound Galaxy Pro16L/Extra (FCC ID: I38-MMSN812 - mine is actually the OEM model Reveal SC400 Rev.2).

That's what I thought too. Some findings to the contrary in the earlier thread: viewtopic.php?f=46&t=46201#p468321
I've never noticed an issue with stereo, but still didn't get around to really testing for it specifically.

[Bancho]

I have come a full circle with my journey of finding the perfect DOS sound card.

Now I own and tested these cards:
SB16 CT2950
SB16 CT2230
SB16 CT2890
ESS ES1688
Aztech SG NX Pro
Aztech SG Pro 16 ABI
Yamaha YMF719E-S

The Yamaha YMF71x is a clear winner in all aspects.
Noise: Very silent.
MPU-401+Wavetable: Bug free, Noise free.
Mixer: Functional with a nice GUI.
PnP: Easily set with a nice GUI.
PCM/Voice: After the capacitor modification the cleanest and most artifact free sound card I've heard in DOS.
OPL: Authentic OPL3.

Ironically it was my first sound card for my Pentium build, which is my only retro build...

Its funny when i was looking for an ISA sound card for my system I was hell bent on getting an AWE64 gold not knowing much about sound cards. I managed to pick up a normal AWE64 and as much as it's a good card, my Sonata 3D card (which is got for £2.99!) with both the YMF719-S and YMF704C OPL4 chip on board is the one that's installed permanently in my machine . Following the advice regarding the mixer settings in the gui and using the correct output it is such a great sounding card. Having the flexibility of authentic OPL3 and wavetable OPL4 sound in one card is awesome.

[James-F]

OK
Duke 3D 1.4 Atomic under sound test with real CT1600 and SBPro 2.0 selected in setup and reverse not checked the sound test plays left and right correctly

Thank you, This is also true with the YMF71x.

even in demos like Future Crew's Panic (you can clearly hear it in the intro sequence).

Sounds correct with YMF71x, but reversed in DSOBox.
DOSBox "fixed" the reversed stereo "issue" when it did not need to be fixed.

That's what I thought too. Some findings to the contrary in the earlier thread: viewtopic.php?f=46&t=46201#p468321
I've never noticed an issue with stereo, but still didn't get around to really testing for it specifically.

CD, FM, Voice... all the sources were reversed? His cable was reversed.
To me it seems that SBPro2.0 has everything alright, no need to switch cables or reverse stereo.

One thing is wrong with the YMF71x, the Wavetable analog audio is actually reversed.
EDIT: I've checked the PCB and Datasheet and indeed, the traces from the wavetable go into the wrong inputs on the YMF chip.
It's MOD time..

[James-F]

Wavetable Reversed Stereo FIX

The Audician 32 has the Wavetable audio return reversed in the PCB itself where the Left channel from the wavetable header goes into AUX2R on the YMF71x chip and vice versa.
Since it is an easy fix I decided to take things into my own hands.

By no means my prettiest job for the lack of proper green trace fix wire, but it is functional and durable.
The channels in the Mixer did not change, only the input from the wavetable.
The first guitar in Doom E1L1 is on the right channel now, as it should.
Side note: The Left channel of the CD cable is the WHITE wire, it goes to pin 1 as marked on the PCB.

Now the Audician 32 is even more better...

[squareguy]

Very nice. If we could only fix the ADPCM issue it would be a perfect card. Thanks for all your work on this!

[PhilsComputerLab]

So how does this now compare to the ESS?

Needing two hardware mods, well, it's great that solutions exist, but not everyone is into modding like that.