CompuServe Thread

Welcome, Rick. I'll let those more knowledgeable deal with your graphics questions and touch on the audio briefly. The Amiga has four audio channels, two tied to each of a pair of line level stereo RCA jacks. All four channels are driven by custom, dedicated hardware, which means you can define a waveform or complete sound, say "play this", and turn your attention to something else. Or, if you're doing something special, you can drive the outputs directly with the CPU. There are several "modes" for the audio outputs. In the most-often used mode, you have available four channels of discrete audio summed into two outputs. Each channel is eight bits modified by an additional six bits of amplitude control; this results in a best-case s/n ratio of approximately 48 db and a dynamic range of about 84 db. It is also possible to stack the channels and use one of each pair to amplitude or frequency modulate the other, resulting in two output channels of complex sound. A third mode allows the channels to be "concatenated", resulting in two channels of approximately 14 bit audio (with, I believe, an additional 6 bits of amplitude control, but this last bit is off the top). <continued>

<continuation> Sampling rate ranges from as low as you want to go to 28,867 Hz. For "instruments" (sounds used by various music programs to play notes), the sampling range generally spans of about 14 to 28 KHz. To eliminate digitizing artifacts, the Amiga includes a reconstruction (antialiasing) filter on the outputs which has a 3 db down frequency response of about 4 KHz. For applications which can use high sampling rates, this filter can be switched out via software. If you have any specific questions about the Amiga's audio I'd be happy to try to answer them. Rick

Rick: Sound is 8 bit, with a 4 voice synth built into the machine. Therefore, you can have 4 separate instruments (or sounds) playing single note lines simultaneously, or you can have one instrument playing 4 mote chords, or you can have any combination which uses up to 4 voices at once. It also has a voice synthesizer built into the standard system software. It multitasks (you can run more than one program at a time). It can support 320×200 or 400 screens with up to 32 colors (64 colors using extra halfbrite mode, but the other 32 are the same colors with half the brightness i.e. a bright green and a muted green, etc.) It can support 320×200 or 400 (pixels) screens with up to 4,096 colors at once in HAM (hold and modify) mode (you have to see this to believe it). It can support 640×200 or 400 screens with up to 16 colors. (BTW, the 400 screens are interlaced, like you TV screen, so on a computer monitor they flicker. However, because they are interlaced (like your TV) you can output Amiga screens and animation to a video tape recorder with interface devices that cost as little as $75.) There are terrific paint, animation and 3-D ray tracing programs available, <continued>

<continuation> many of which can use sound simultaneously with the animations. There are a number of good music programs, and the machine can support MIDI (musical instrument digital interface), which can let you control external synthesizers from the computer to let you have many, many voices (virtually as many as you can afford to buy). I use it for all of the above, and bought it for the music and graphics. After I had it, I found it to be the most flexible, most powerful, and most fun computer I have ever worked with. By all means get one. Finally, the best "intermediate" level configuration for an Amiga 500 is two disk drives and a full meg of RAM. that would probably take your all-in purchase price to about $1,100. If you can't handle that, I would strongly recommend that the extra drive, and extra half meg of ram be the first things you add to the system (in that order). & y'all come back here with any questions (you will probably have some. Amy is different, and can be confusing at first, even if you hav eused other computers. You can get up the learning curve pretty quickly though, and have gobs of fun.) Ray Lewis