My sb16 was noisy until i disabled onboard amp by changing the jumper settings. Couldn't be happier with it right now, great card.

if you check their snr ratings it's pretty poor.
And vs later PCI cards you do hear extra little pops and crackles and hissing.
But we are talking about DOS gaming, it's not like the recording quality is amazing, typically quite the opposite, low bit rate compressed within an inch of its original size.
I'd happily have any in one of my builds.

I tested the output of several SB16 cards with RightMark Audio Analyzer a few years ago, where the internal amplifier of each card was disabled (or the dedicated line output jack was used otherwise), and leveraging a set of optimized mixer settings.

The measured noise levels are considered "good," even by today's standards.

I am under the impression that most people when they talk about noisy cards they don't usually mean the lab measurement of noise, but rather how susceptible the card is to pick up interferences/computer "thinking" noises.

konc wrote on 2023-04-19, 17:07:

I am under the impression that most people when they talk about noisy cards they don't usually mean the lab measurement of noise, but rather how susceptible the card is to pick up interferences/computer "thinking" noises.

It would be nice to know if that's actually an issue or not, or if it's just an assumption based on known/valid behaviors of earlier Sound Blaster cards. For my part, I haven't found any SB16 to be susceptible to bus-noise, nor have I encountered any confirmed accounts of such behavior.

Cloudschatze wrote on 2023-04-19, 17:25:

konc wrote on 2023-04-19, 17:07:

I am under the impression that most people when they talk about noisy cards they don't usually mean the lab measurement of noise, but rather how susceptible the card is to pick up interferences/computer "thinking" noises.

It would be nice to know if that's actually an issue or not, or if it's just an assumption based on known/valid behaviors of earlier Sound Blaster cards. For my part, I haven't found any SB16 to be susceptible to bus-noise, nor have I encountered any confirmed accounts of such behavior.

Just to be clarify, I wasn't referring specifically to the SB16 but in general to what I think many people consider to be a noisy sound card.

Cloudschatze wrote on 2023-04-19, 17:02:

leveraging a set of optimized mixer settings.

That's likely the key point. When I first got a sound card, I first used a dictaphone-quality headphone on it, that likely cut off at around 5kHz. When I got better phones, my brother complained that the sound is bad. I verified it, and confirmed a much brighter sound with a very annoying hiss in the background.

Then I learned that PCM=20%, FM=20%, Master=90% is a very bad mixer configuration, and PCM=90%, FM=90%, Master=20% got rid of the noise. That's obviously the base noise on the internal mixing bus.

mkarcher wrote on 2023-04-19, 18:36:

Then I learned that PCM=20%, FM=20%, Master=90% is a very bad mixer configuration, and PCM=90%, FM=90%, Master=20% got rid of the noise. That's obviously the base noise on the internal mixing bus.

This is an important point. I set my mixer settings to Master=100%, Wave=100%, FM=100%.

I do get some weird noises when I turn on the CD sound, so I keep it at 0%. That would probably be bus noise coming through the analog CD audio cable, which isn’t shielded at all.

This makes sense, I think. 🙂👍
From what I know, not using amplifiers results in a lower noise floor (in general).
However, it's counterproductive if the source signal is close or below the noise floor.
So increasing mixer volume can produce a higher quality audio output (better SNR), aslong as no overamplification/no distortion is happening.
But that's obvious, likely. I'm just thinking out loud here.

I have a Wang 386 computer that has 0 electrolytic capacitors. The bus noise coming through the SB 2.0 that was in it was horrid.

Put the card in a board with filtering caps and unsurprisingly all that noise magically disappeared.

What also helps with that noise is using newer power supplies that actually put out pretty clean power compared to the horrid power supplies of 'yor.

I have also noticed that other components seem to run a lot cooler when using modern power supplies.

Cloudschatze wrote on 2023-04-19, 17:25:

konc wrote on 2023-04-19, 17:07:

I am under the impression that most people when they talk about noisy cards they don't usually mean the lab measurement of noise, but rather how susceptible the card is to pick up interferences/computer "thinking" noises.

It would be nice to know if that's actually an issue or not, or if it's just an assumption based on known/valid behaviors of earlier Sound Blaster cards. For my part, I haven't found any SB16 to be susceptible to bus-noise, nor have I encountered any confirmed accounts of such behavior.

I had a SB2.0 in 1993 and it picked up interference like an aerial. I spent around 2 months trying to fix it and then asked the school computer tech what could cause it. He said he was 99% sure it was caused by the Hard drive.
His fix was to get a square piece of iron, around 8cm by 8cm with a depth of 1cm. He taped it with electrical tape all around and told me to place it between the sound card and hardrive (this was a dekstop case, not a tower). It worked, no noise. I had that in my case until 1995 then threw it when I upgraded.

Hmm interesting so it also depends on your motherboard and power supply. That would make sense.

I do have an SB 2.0 that I've been meaning to put in a build. I'm interested to see how noisy it is.

Fwiw I also have an old Sony receiver that blew a capacitor recently and is now very noisy, picking up every bit of the bus/drive noise from the computer next to it.

DMA clicking bug is the reason why I don't want to use those old SB16 cards. But with internal amplifier they are noisy. I don't think I've ever tested those CT17xx cards with amplifier disabled. But I'll sure have to try someday.

But about bus noise. I did lots of CPU tests with ASUS VL/I-486SV2GX4 (SiS 471 based 486 VLB motherboard) and used CT1600 (Sound Blaster Pro 2) for OPL3 speed tests. Bus noise could be easily heard when I forgot speakers on. Just now I've used the very same card with similar testing using ASUS P/I-P55T2P4 (REV. 3.10). That is a Pentium motherboard with HX chipset. I could not hear the bus noises even though I tried to (with headphones). I think I used modern ATX power supply with the 486 test and this time old AT power supply with Pentium tests. So motherboard made the difference. Could it be because ISA is bridged so more "shielded"? Or maybe simply because the Pentium motherboard had integrated PCI IDE while the 486 had VLB IDE and so hard disk was much more visible to the ISA bus?

aitotat wrote on 2023-04-22, 09:23:

But about bus noise. I did lots of CPU tests with ASUS VL/I-486SV2GX4 (SiS 471 based 486 VLB motherboard) and used CT1600 (Sound Blaster Pro 2) for OPL3 speed tests. Bus noise could be easily heard when I forgot speakers on. Just now I've used the very same card with similar testing using ASUS P/I-P55T2P4 (REV. 3.10). That is a Pentium motherboard with HX chipset. I could not hear the bus noises even though I tried to (with headphones). I think I used modern ATX power supply with the 486 test and this time old AT power supply with Pentium tests. So motherboard made the difference. Could it be because ISA is bridged so more "shielded"?

Possible. Another reason that came to my mind is that the P45C CPU and the Intel HX chipset run off 3.3V, so the regulator for that voltage dampens some of the current spikes generated by the CPU and chipset.

Also, as the HX main board has more integrated peripherals, it is likely that in the VL board there was a card in the neighbouring slot that caused radiated interference, whereas in the PCI board, the only plug-in card besides the SB Pro is likely the graphics card, and many people plug the ISA sound card in the "bottommost" slot and the PCI graphics card in the "topmost" slot, so there is a lot of distance. (top/bottom refers to the location in a standard AT tower case)

I just had to test it since the ASUS P/I-P55T2P4 is on the test bench at the moment. I compared bus noises from ISA multi-i/O card against the onboard PCI controller (for some reason I had to use XTIDE Universal BIOS to get the ISA card working. System BIOS did not found the hard disk when onboard IDE was disabled). DIR /S /W the hard disk contents and you can easily hear what is going on when using headphones and volume is at maximum. In fact, you don't have to go that far. I could hear the hard disk spinning up from the headphones when powering on the system.

But with CT1600 I could hear the bus noises when using ISA multi-I/O card and with the onboard controller as well. Maybe the ISA was a bit worse, maybe not, I'm not sure. Both could be heard so if there was difference, it was small and not significant.

But this was just perfect time to test the "high quality" Sound Blaster Pro 2, CT1680. Unlike CT1600, it has a good quality PCB with ground plane (like SB16 CT17xx cards have). And no bus noises, not with ISA controller or with onboard PCI controller. I kept the volumes at maximum. So indeed the CT1680 is better quality card than the common CT1600. I think the CT1680 is the only Creative SB Pro with ground plane.

It was a bit hard to take a picture but this shows the the difference between cards quite well.

aitotat wrote on 2023-04-22, 10:38:

But this was just perfect time to test the "high quality" Sound Blaster Pro 2, CT1680. Unlike CT1600, it has a good quality PCB with ground plane (like SB16 CT17xx cards have). And no bus noises, not with ISA controller or with onboard PCI controller.

If the ground is the reason the CT1680 has less noise, it is likely that you don't deal with conducted interference (noise getting into the card from the ISA pins), but with radiated interference (noise getting into the card from electromagnetic radiation inside the case). But possibly the reason for less noise is also other design changes like better voltage regulators or lower impedance capacitors rejecting supply ripple. No matter what the technical reason for the improved noise performance really is in your system, your experiment shows that the CT1680 is advantegeous compared to the CT1600.

The pentium asus board, I know this one well as I had rev 3.10. The 3.3V is from linear regulator, while VCC2 (second plane) for CPU vcore, 2.8V with different voltage selections like running K6-2 comes from switching regulator through a inductor.

The noise is more noisier if the i/o and IDE cards were 2 layer ditto to any cards. Until more cards now have 4 layers then less noise.

Cheers,

aitotat wrote on 2023-04-22, 10:38:

I think the CT1680 is the only Creative SB Pro with ground plane.

But wait, there's another! 😉