First post, by Kordanor
Heyho!
I got an ESS ES1868F Soundcard and I am actually quite happy with the Sound quality itself. However the ISA noise can be quite annoying. I wanted to create this thread to share some experience and maybe you got some other suggestions on what to try.
I also tested a PCI card instead and ofc that one doesnt have any noise. In my case I had at SB Live at hand. However the Music was in DOS games was absolutely terrible. Maybe you have a good suggestion for a PCI Card which I could use having a better music quality (my intention was to just swap via boot menu, and plug in the speakers to the card to be used).
Just for completelness I also tried a different board, but it's the same.
Here are the things I found with my ISA Card:
It seems like a significant amount of Noise comes from the CD Drive. If its spinning you can hear a clear Bup-Bup-Bup-Bup in the background. My guess is that its the power going to the CD drive which causes some fluctuations. The cable is not running next to the soundcard btw. My guess: If you got an Additional Power connector for the soundcard you could eliminate this. I didnt have one at hand and unfortunately its also not really practical to have two PSUs. Maybe you have some other idea? Maybe a "buffer" of some sort which could be attached the the CD Molex connector (if it actually is the power and not the IDE connection)
I also noticed that on high CPU Speed the noise is significantly worse than with low speed. This became quite apparent when I started up Jagged Alliance. While I am in the menu, there is no noise. But once I am on the map and scroll over a map with lots of bushes, the background noise gets intense. In difference to the CD Drive noise which is Bup-Bup-Bup its more like a weeeeeeeeeaaaaaaaaap as long as you are scrolling over the forest. Almost like a coil whine, just a bow lower frequent. It seems to be a combination of graphics and CPU usage. Reducing the CPU from 500Mhz to 167 Mhz gets rid of the majority of that.
Lastly I removed some noise via external processing. Obviously that can only be used if you use the sound as LineIn on another machine which can process that.
I found a program called Pedalboard 2. https://www.niallmoody.com/work/pedalboard2/
Its a very cool program, but it can't do magic. You can set up noise reduction and equalizers to the pipeline. And works perfect for removing the standard white noise. But the noise like described above from CPU or Drive can only be removed with costs in other sound quality. For example if I filter out the Bup-Bup-Bup of the drive, then I also kill some of the drums in the music.
So what are you experiences, got any additional tips?