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Yamaha YMF71x SB Pro Mixer Bug Issue Fix

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Reply 100 of 183, by James-F

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clueless1 wrote:

Can you help me understand why that is bad? 10V doesn't seem like an amount that would hurt anything, but I'm pretty uneducated on the topic.

You will not get electrocuted from 10V that's for sure. 🤣

We are talking about line level here: https://en.wikipedia.org/wiki/Line_level
Consume line level, Red/White RCA plug on hardware like DVD/TV/Recievers/etc.. or Line-out on sound card, is mere 0.447V Peak.
4.4V Peak, is not consumer or professional audio line level, but many many times above, this is speaker level voltage.
The transistor that is designed to receive the audio signal before the amplifier has a rail to rail (peak to peak) of probably +-2.5V, and will undoubtedly distort.

Please read the Wiki page, it is very informative and everyone who deals with audio should know.

EDIT:
For the lack of better place here is a SB2.0 CT1350B sample to the next post.

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  • Filename
    SB2.0.mp3
    File size
    118.59 KiB
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    25 downloads
    File comment
    CT1350B
    File license
    Fair use/fair dealing exception
Last edited by James-F on 2017-04-18, 04:37. Edited 3 times in total.


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Reply 101 of 183, by James-F

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As a final media contribution to this thread, I present an audio comparison of various sound cards and their lowpass filters.
The sample is Doom shooting the Chingun, this should give a pretty good reference.
All volume matched to 0.5db below 500Hz, so the bass frequencies are align perfectly on all tracks.

Attachments

  • Filename
    Unfiltered.mp3
    File size
    146.65 KiB
    Downloads
    185 downloads
    File comment
    Stock YMF71x
    File license
    Fair use/fair dealing exception
  • Filename
    SBPro2.mp3
    File size
    142.07 KiB
    Downloads
    159 downloads
    File comment
    Real deal SBPro2 CT1600.
    Provided by firage.
    File license
    Fair use/fair dealing exception
  • Filename
    YMF719 Modded.mp3
    File size
    130.1 KiB
    Downloads
    172 downloads
    File comment
    6.8nF
    File license
    Fair use/fair dealing exception
  • Filename
    SB16.mp3
    File size
    118.75 KiB
    Downloads
    152 downloads
    File comment
    CT2230
    File license
    Fair use/fair dealing exception
  • Filename
    DOSBox.mp3
    File size
    127.38 KiB
    Downloads
    121 downloads
    File license
    Fair use/fair dealing exception


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Reply 103 of 183, by gdjacobs

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James-F wrote:
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clueless1 wrote:

Can you help me understand why that is bad? 10V doesn't seem like an amount that would hurt anything, but I'm pretty uneducated on the topic.

You will not get electrocuted from 10V that's for sure. 🤣

We are talking about line level here: https://en.wikipedia.org/wiki/Line_level
Consume line level, Red/White RCA plug on hardware like DVD/TV/Recievers/etc.. or Line-out on sound card, is mere 0.447V Peak.
10V Peak, is not consumer or professional audio line level, but many many times above.
The transistor that is designed to receive the audio signal before the amplifier has a rail to rail (peak to peak) of probably +-2.5V, and will undoubtedly distort.

Please read the Wiki page, it is very informative and everyone who deals with audio should know.

Any line level output will have significant series impedance, so you'll likely be safe even if you stab yourself with connected leads.

All hail the Great Capacitor Brand Finder

Reply 104 of 183, by James-F

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There is a thing call safe touch voltage or "extra-low voltage".
Typical minimum skin resistance is around 1.6k and 30mA can kill you. so 1600x0.03 = 50v.
50VAC RMS is the standard for "extra low voltage" and the maximum voltage you can safely touch with your bare hands.
This is another topic altogether and far from what a sound card can produce.

The point is to get clean audio signal and stay in the standard voltage line levels to prevent distortion without knowing anything about the circuitry of the interconnected hardware, that's why there is a standard.
Electrocution is not of any concern in this matter, clean distortion free audio is.

Yep the mod really improves that awful 'dry' output, well done James.

Yeah, I'm waiting for other people to do the mod and report with cheerful posts. 😀

EDIT: For those who already bought 4.7nF caps, the sound will be somewhere between the SB2.0 and SBPro which will sound great.
From what I hear the SB2.0 is slightly less filtered than the SBPro, but not entirely without a filter like some believe.

EDIT2:
The Sound Blaster Programming Guide states for the SBPro (CT1345 mixer):

Turn off the filter for high sampling rates or stereo output.

Indeed I have encountered games that sound really muffled with the filter enabled like Duke Nukem 3D which uses SBPro Stereo and high sampling rates, it dos not disable the filter automatically.
Other games like Doom, Heretic, Hexen, Archon-Ultra, Descent, automatically enable the filter when entering the game.
Most older games don't care if the filter is on or off, but expect it to be always On like on the SB2.0.
It is safe to say that with high sampling rate games like Duke3D the filter should be off, but most games switch the filter on/off and Stereo mode automatically as they need, Quake is one of them.
In other words, if the developer was aware of the SBPro Stereo switch, here was also aware of the Output Lowpass filter switch which is available only on the SBPro.


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Reply 105 of 183, by Jolaes76

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I have all sorts of YMF 71x cards and what I have found by swapping the software (setupsa v2.09 and v2.11 as suggested in this thread) among them is a NO-GO.
For my Audician 32 v2.09 works much better, I can make the card co-exist with an SB16 without issues occupying different resources,
whereas using setupsa v2.11 taken from the Win3x installer makes digital sound disappear, cut-out or slow the computer down. All these appear DMA issues to me.
I suspect along with the default values offered for WSS (DMA 0, 1, 3 vs DMA 0, 1, 5) there are other differences between the two setupsa.exe like different powerdown value for the codec etc. These might correspond to actual hardware differences between YMF715/718 and YMF719 cards.

"Ita in vita ut in lusu alae pessima iactura arte corrigenda est."

Reply 106 of 183, by PhilsComputerLab

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James-F wrote:

EDIT2:
The Sound Blaster Programming Guide states for the SBPro (CT1345 mixer):

Turn off the filter for high sampling rates or stereo output.

Interesting. So what about the dynamic filter on the SB16 for high sample rates and stereo outputs? In such cases, is it "good"?

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Reply 107 of 183, by James-F

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Jolaes76 wrote:

(setupsa v2.09 and v2.11 as suggested in this thread

Where exactly did you see the version number?
Maybe the INI file tweaks itself according to the YMF71x card during installation?

PhilsComputerLab wrote:

Interesting. So what about the dynamic filter on the SB16 for high sample rates and stereo outputs? In such cases, is it "good"?

By "Dynamic" it means the filter moves with the sampling rate.
According to Nyquist Theorem to measure or recreate (DAC) a frequency without aliasing the sampling rate has to be at least twice the measured/recreated frequency.
Human hearing tops at 20,000 Hz, so a DAC with sampling rate of 44,100 Hz will recreate all the frequencies that a humans can hear without aliasing.

With 44,100Hz sampling rate the filter will be at half this frequency at 22,050Hz, which is outside of human hearing, like a CD player or any modern hardware.
With 11,000 sampling rates like most DOS games the filter will be at 5,500Hz and eliminate everything above than, like in the images I've posted.


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Reply 108 of 183, by PhilsComputerLab

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Yup, I understand all of that. My question was, with the SB Pro having a fixed filter at around 3.4 KHz, doesn't that mean that at high frequency samples, the SB 16 will sound better because the filter is adaptive, whereas the SB Pro will cut off too much from the higher frequencies?

Or could we please have graphics for 22 and 44 KHz, just to get the full picture?

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Reply 109 of 183, by James-F

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PhilsComputerLab wrote:

My question was, with the SB Pro having a fixed filter at around 3.4 KHz, doesn't that mean that at high frequency samples, the SB 16 will sound better because the filter is adaptive, whereas the SB Pro will cut off too much from the higher frequencies?

Correct, the SBPro doesn't know or care at what sampling rate frequency you play, it will always have the same analog filter.
That is why is was so easy changing the caps to alter the simple analog filter of the SBPro.
So YES, even high sampling rates PCM sounds will be filtered by the SBPro, that's why the Programming Guide suggested disabling it with anything above 11kHz,
but if the game was programmed correctly the devs should have included the command to disable the filter if a SBPro card is used with higher sampling rates.

I wouldn't say "too much" because the SB16 cuts more in 11kHz sampling rate than the SBPro, but less in 22kHz sampling rate.
So anything above 11kHz sampling rate would benefit from disabling the SBPro filter.

The SB16 has a digital brickwall filter like modern CD/DVD/BluRay/MP3 players, or the DAC of the sound card in your laptop computer, etc..
This digital brickwall filter will cut anything above half the sampling rate, and because it is digital it can be moved (reprogrammed) easily.

One can conclude that the SBPro is absolutely not designed to play quality Stereo sound at 44.1kHz, but old 11kHz DOS games, which is fine by me. 😀

The two blue lines are how the SB16 will filter 11kHz and 22kHz sounds, the Orange line is how a SBPro will ALWAYS filter.

Filters.png
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Blue line is at 22,050 Hz sampling rate.
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Last edited by James-F on 2017-04-18, 04:42. Edited 2 times in total.


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Reply 110 of 183, by PhilsComputerLab

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Ah that makes sense.

Now a SB16 related question. Is it possible to change the "steepness" or "strength" of the filter? So what I mean is keep the filter being adjustable, but less aggressive?

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Reply 113 of 183, by James-F

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Digital... meaning it is a program inside the DSP, so no soldering will ever help... 😀
Well, only if you want it to be absolutely silent... 🤣 🤣 🤣

Last edited by James-F on 2016-09-25, 14:52. Edited 1 time in total.


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Reply 114 of 183, by Jolaes76

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setupsa v2.09 and v2.11 as suggested in this thread

Where exactly did you see the version number?
Maybe the INI file tweaks itself according to the YMF71x card during installation?

The version numbers are displayed when you run "setupsa.exe /s" at the command prompt, but you can also find them easily in each setupsa.exe with a hex editor at about 87% of the file.

You should see sg like this:

"OPL3-SA3C Setup Utility 2.11"

And yes, it is possible that the ini files generated by different versions of setupsa.exe are not entirely compatible.

Another "issue" I found: Audician 32 with the v2.11 mixer: Low DMA 3 cannot be forced, not even by manually editing the OPL3SA.INI file.

"Ita in vita ut in lusu alae pessima iactura arte corrigenda est."

Reply 115 of 183, by PhilsComputerLab

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I think for the Audician32 Plus I will stick with the supplied DOS installer and version of the driver. I never had any issues with it 😀

Keen to get the resistors. I will mod one card, keep the other one stock.

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Reply 116 of 183, by James-F

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If that is the case, may it is best to keep using the Setupsa provided with the Audician 32 disc.

PhilsComputerLab wrote:

Keen to get the resistors. I will mod one card, keep the other one stock.

Good idea.
But even with the modded YMF you can always disable the Filter just like you did with the SBPro card using the SBPro mixer; it will sound just like the unmodded card.


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Reply 117 of 183, by PhilsComputerLab

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James-F wrote:
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If that is the case, may it is best to keep using the Setupsa provided with the Audician 32 disc.

PhilsComputerLab wrote:

Keen to get the resistors. I will mod one card, keep the other one stock.

Good idea.
But even with the modded YMF you can always disable the Filter just like you did with the SBPro card using the SBPro mixer; it will sound just like the unmodded card.

Oh that's pretty cool then 😀

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Reply 118 of 183, by James-F

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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... 😀

EDIT:
Now I own a few more cards;
SB1.5 CT1320C
SB2.0 CT1350
SBPro2 CT1600

Last edited by James-F on 2017-04-18, 04:43. Edited 3 times in total.


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