Author Topic: MIDI and Sound Cards  (Read 2354 times)

Fractilion

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MIDI and Sound Cards
« on: November 26, 2007, 03:23:35 AM »
How do sound cards effect sound behavior of the computer? I have an idea but I'm not sure. Can you get sound cards that dont have shitty MIDI sounds? Do sound cards effect the amount of frequencies of sound the computer can process?

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Bobbias

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Re: MIDI and Sound Cards
« Reply #1 on: November 26, 2007, 06:39:09 AM »
I'm warning you now, I may get VERY technical at times.

Ok, first off, about the MIDI question.

MIDI has standard sounds. Any soundcard with midi uses the same set of basic sounds. However, there are other ways of rendering MIDI data. Those sounds are stored in a little chip in the soundcard. They are then played out when they are triggered by the midi input. However, if you have ever changed the midi output in a program to "Microsoft GS Wavetable" you'll notice that the sounds are different. Most computers have the option of using the Microsoft GS wavetable output as an option even if there aren't any MIDI sounds stored in the card itself. I'm sure spectere knows more about the sound card hardware aspect as I do, but let's suffice to say that pretty much ever sound card you see now will have the default sounds on it.

There are some cards, however, than can do something more. They are capable of using something called a "Soundfont" a Soundfont is a file which contains audio samples which can be placed in a special chip on the sound card that will use those samples instead of the default ones shipped with the soundcard. However, not all soundfonts replace every instrument. That is actually really rare, because most soundfonts aren't designed to be used that way. They are designed to replace specific sounds and be used in a program like FruityLoops. My brother wrote some music in MIDI and wanted to convert it to MP3. Since I didn't know how to record the speaker output ("What U Hear", on a lot of sound cards), I opened FruityLoops, loaded some soundfonts, and used those to render it into MP3.

Another option that some cards have is the ability to relay those MIDI commands from the sound card into other things. For example, you can control Drum Machines with MIDI. Or you could hook up a hardware Synthesizer to it and send it signals through MIDI. Your computer would not be generating any of the default sounds any more, since the synthesizer would be doing that for it. All it did was relay the MIDI signals through the cord into the synth.

Anyway, on to the other part.

I hope you have some concept of frequencies and such, because I'm going to assume you do have some knowledge.

For the most part, your soundcard can output any frequency to your speakers, within a certain range. When you see people talking about MP3s or wave files, there are generally 2 numbers they talk about, the bitrate, or, how much information it takes to describe 1 second of sound, and the sample rate. The sample rate is how often the MP3 or wave file describes the state of sound. That is, each sample of sound. The sample rate is how many of those samples the computer processes in a second. The default number for most things is 44.1khz, or 44 100 Hz. That means there are 44 100 samples in each second of sound in that file. By knowing the sample rate, we also know the highest frequency that it can play back. At a sample rate of 44.1khz, the computer can play back anything from 1hz to 22 050hz (22.05khz). Why only half of 44.1khz? Because if you remember, sound is a wave, and a wave needs to have both an up, and a down to be complete.

If sample 1 were to show the speaker in a up position, and sample 1 showed the speaker in the complete opposite, a down position, and the rest of the file was this repeating over and over, we would have a file that when played, resulted in the frequency of 22.05hz being played continuously. The files are more complex than simply having an "up" and a "down" position, but we don't need to care about that right now.

Now, every sound card you would ever buy now can at LEAST support playing back files at 44.1khz. In fact, almost every single sound card nowadays can support playing back up to 96khz, which means that you could hear up to 48khz being played back to you. BUT, that doesn't really matter, because the human ear cannot hear anything higher than about 20khz. In fact, thanks to all the damage I've done to my ear, I can't hear much above then level of 13khz now.

If you have any more you want to know about this, just ask, I'm not much on the hardware part, but any technical stuff about sound, I can answer (thanks to extensive research, reading a book called "the physics of sound", and working in my highschool's recording studio for a semester, I know quite a bit more than most people my age. Or any age.)
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Fractilion

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Re: MIDI and Sound Cards
« Reply #2 on: November 26, 2007, 02:12:54 PM »
Thanks. And don't worry. I'm familiar about a lot of this stuff. I've been doing extensive research myself. I'm in my first year of college now and I just started doing a lot of independant studies. It's fantastic that you've started doing that as early as high school. You'll go far having that kind of a head start. I guarantee it. But yeah. I got a drum trigger recently, by the way. With a midi output and .wav input by use of memory cards.

I even like to dream when asleep, and to try and recall my dreams: it assures me that I haven't wasted seven or eight hours just lying there.
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Bobbias

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Re: MIDI and Sound Cards
« Reply #3 on: November 26, 2007, 06:14:01 PM »
Cool. I don't have a job, or I'd likely have a drum trigger too. Well, I began research early in highschool. I've always wanted to learn things on my own, and music is something I've always loved, so it just seemed naturla to learn about sound, and how computers worked with it.
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Alice

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Re: MIDI and Sound Cards
« Reply #4 on: November 27, 2007, 11:57:34 AM »
HAI DUZ N-E-1 HAEV A PROGREM DAT MAEKS UR PSF FIELS INTO MEEDEES?!!1/