there may be software that lets you create sfx with the synth chip on the sound card. but you'd need a way to save it as a wav for later playback. back in the day, programming the OPL3 chip (via port 220H as i recall) was a common way to create synthy type sfx.

Modern computers generally don't have audio synthesizer hardware anymore - there's not much of a point when synthesizing audio on the CPU takes a literally negligible amount of CPU time. (Which is also why dedicated sound cards are also nearly extinct.)

there may be software that lets you create sfx with the synth chip on the sound card. but you'd need a way to save it as a wav for later playback. back in the day, programming the OPL3 chip (via port 220H as i recall) was a common way to create synthy type sfx.

Modern computers generally don't have audio synthesizer hardware anymore - there's not much of a point when synthesizing audio on the CPU takes a literally negligible amount of CPU time. (Which is also why dedicated sound cards are also nearly extinct.)

mmmm maybe you talk about built in sound cards, but actually now is the time when any person who work with recording and audio processing should have a sound card ,is a must have, this is because some plugin's called DSP (digital sound processing) required a lot of CPU and they have a better sound quality , these can be sound processors and even sintetizers and if you don´t have an external sound card the plugin's won`t work.

if you want to make sound with the oscilator of the computer there is a program called "Super Colider" is a sintetizer that works with mathematical functions and computer language and for me is really complicated to use :(

if you want to make sounds like the chip cars i recommend you to use Reason or almost any modern synth haha those sounds are really easy to make , i can show you how if you guys want .

If Bfxr is too retro for you, try some synths. Get a DAW like Reaper (free/~60$) or Logic X and then some simple VST instrument synths like Synth1. Start experimenting with the synths or watch some youtube tutorials or whatever. Record and edit some sounds in the DAW. Use EQ, pitch tools, automation, compressors/saturation etc. to get more interesting sounds out of the recorded.

That's the basic stuff.

Of course you can download some sounds and try to edit those to be more suitable to your projects. Or get a mic and start recording. You can get nice sounds with your mouth and some drastic editing. Just start experimenting. Set some goal like a short gameplay video with your sounds and post it here when finished :)

Pro tip: slap some reverb on almost any retro sound, and it immediately sounds more futuristic.

A good reverb makes everything sound better almost no matter how bad the original was.

If you can get to a music store, go play with the synthesizers. Controlling the sound of synths is tough to the point where most pros don't. They just spin the dials until something good randomly comes out (or use presets that someone else created). Even when you know what you're doing, you tend to default to that. Although there's a several different types of synthesis and it all works differently. A lot of it is just buzzers that you apply filters and effects to. So, if you learn about the filters and effects you've learned a lot of how to control it. FM synthesis is more complicated, but I rarely see that used since it was over used in the 80's.

But anyway, you might get some ideas of how to create electronic sounds from playing around with synths. For more realistic sounds, it seems like it's more a matter of actual recording an actual sound. I know a lot about recording, but don't necessarily know much about folly and sound design although I did take synthesizer programming classes from Berklee. Speaking of which, you might want to take a look at their online classes if you can afford the arm and leg they charge. But I can vouch for the fact that they have some of the best teachers in the world.

What do you think how long would it take to learn to make quality sounds from scratch?

There's no answer to your question. Depends how much you know about sound, how long you're practicing per day, how quickly you learn and how creative you are. Maybe weeks, maybe months, maybe years. And most importantly when do you think you're ready with your sounds. Some of us think that we're never ready and some are satisfied with less.

So the actual answer to your original question: "Should i try to make my own sounds?"

Yes you should and you should start practicing right now!

Do research for free sample packs of what you are looking for.

Or

you can always talk to some one like me who manipulates/edit audio and get specific content.