Well, the 1.5 and 2.0 do not have a mixer. AFAIK the SB Pro was the first Creative card with a mixer.

This SB Pro stuff does interest me lots, but I just do not have the time currently. Too many projects I'm working on already. Someone send me some free time 😵

Thanks Phil, when you'll have the time a recording of the story intro of Prince of Persia 2 with a SB 1.0/2.0 will be perfect for testing to get this thread going and find a perfect balance between FM and PCM for newer SB cards.

I've had an SB Pro v2 in my machine for years, and I basically always had the mixer flatout on the FM and DAC channels, and controlled the overall volume with the dial on the back.
The SB Pro's mixer was designed to have the same balance between FM and DAC as the earlier SBs had 'hardwired', so there was never any need to adjust anything.
PC speaker and CD-rom were a different story, since they are somewhat system-dependent. I didn't run the PC speaker flatout, because it was quite loud.

PhilsComputerLab wrote:

Well, the 1.5 and 2.0 do not have a mixer. AFAIK the SB Pro was the first Creative card with a mixer.

Yup, I think James-F means the analog mixing circuit, which combines the synth and the DAC audio and passes it to the amplifier.
Don't know for sure, but I think that "mixer" consists of a few caps and resistors. If we find out the right balance,
we can program the real mixer on a SB Pro/16 to the right setting for older games.
Nice project! 😀

Edit: Quote added. Why are you people always so fast ? 😢

Jo22 wrote:

Yup, I think James-F means the analog mixing circuit, which combines the synth and the DAC audio and passes it to the amplifier.
Don't know for sure, but I think that "mixer" consists of a few caps and resistors.
If we find out the right balance, we can program the real mixer on a SB Pro/16 to the right setting for older games.

Precisely!
And there are tons of older games that rely on the fixed balance of the older SB cards.

Each sound card is different, so we need to find an easy way to balance the FM and PCM sounds with these new cards including dosbox.
The most precise way would be to play a sine from the FM and then from the PCM through an old SB card, and take the peak readings of both.
Then do the same with the new SB card and tweak the mixer to have the same peak ratios.
But a simple recording of PoP2 intro would suffice to adjust by ear.

Okay here is the perfect way to record the old SB balance:

All you have to do is hit the record button on your new PC and play the opl440.com for a couple of seconds on your old PC with the SB 1/2 card.
Then play the 440_0db.WAV for a couple of second (command: MPXPLAY.EXE 440_0db.wav) on your old PC.
Now we have a true FM to PCM volume ratio recording from an old SB card.

If anyone willing to help, I would greatly appreciate it.

Nice.

Just in case anyone is wondering, the OPL440 sets the channel to additive synthesis mode, so the sine wave amplitude is actually sum of two operators running at full volume.

As some SB cards have also the CMS chips, for completeness sake, it would be nice to test the mixing level of CMS audio too.

Yep, Adlib Tracker confirms.
I can generate the exact same signal using the AM connection with sinewave on each operator at full volume.

But I still need the SB2 recordings to accomplish something for the good of all dos gamers. 😎

I wrote a tool to get 440 Hz tone from the CMS chips. Should work with SB 1.x and SB 2 cards with CMS chips installed. I haven't tried it with my SB 1.x yet, but it emits a tone under DosBox (although about 490 Hz because DosBox CMS emulation is a bit off with the chip clocks).

If you want I can post it here too, but the topic was strictly about FM and PCM volume balance, not CMS 😀

Please go ahead, we are doing science here not playing games.
Hope someday someone will be generous enough to participate in this experiment and provide a recording of his SB. 😀

Well, here it is. Feedback appreciated, if anyone has a Gameblaster or SB with CMS chips at hand.

Again, currently works only for CMS chips at 220H, but should work on SB 1, SB 2 and GameBlaster as they are all identical regarding the SAA1099P chips. Rumors say accessing cards with logic to lengthen CMS write cycles without CMS chips actually present may hang the system.

Hello, everone. I've done some recordings for you.
I have used sound cards from my own little collection. They all work, but are also quite old.
Perhaps some caps need to to replaced to restore former sound quality.

A few more..

Finally! This is great, thank you Jo22!

Question,
Is it the recordings of the following?:
OPL440.com
MPXPLAY.EXE + 440_0db.wav

What is first, what is second?

Hi, there! Glad I could help! 😀

Yes, FM first, then the wave sample.

Btw, I've a few more cards to test..

Few more cards? This would be great!
The Aztech and the Clone have some serious distortion in the WAV sample, but the Creative and QuickShot are clean.

I am going to produce DOSBox FM to SB level matching ASAP.

EDIT:
There is exactly 8.5db difference between FM and WAV on both Creative and QuickShot cards.
To recreate that in dosbox with Nuked-OPL, FM should be set to 75, not 100.
The following command should recreate a perfect balance between FM and PCM in DOSBox with Nuked-OPL patch.

1mixer fm 75

@Jo22
Can you please also make a recording of the CMS along with OPL and WAV with the CT1350, attached by Jepael before your post.

Also, can you please record the intro song from the game GODS with the CT1350 card?
This should give another perspective of balance with actual content, since the SB2.0 also filters the OPL to some degree.
It is around 2:30 minutes long.

James-F wrote:

@Jo22 Can you please also make a recording of the CMS along with OPL and WAV with the CT1350, attached by Jepael before your pos […]
Show full quote

@Jo22
Can you please also make a recording of the CMS along with OPL and WAV with the CT1350, attached by Jepael before your post.

Also, can you please record the intro song from the game GODS with the CT1350 card?
This should give another perspective of balance with actual content, since the SB2.0 also filters the OPL to some degree.
It is around 2:30 minutes long.

I would love to do this, perhaps in the next three days. I have to make sure I get my GAL chip correctly programmed.
The Philips SAA1099 chips are already here. 😀
Is a REV 4 card fine for the CMS upgrade ?

And once more..

Excellent!

The SB 2.0_new has exactly 8.5db difference like the previous you posted, and they both sound and measure very clear.
The QuickShot SoundMachine looks like an exact replica of the Creative and sound like one, great card.

Do you have a SB 1.0?
Can you please do one recording with CMS too with the CT1350B?
EDIT: Sorry I misunderstood your previous post, Yes the REV4 will be fine, hope the programming will go easy.