Xref: utzoo comp.sys.amiga.audio:419 comp.sys.amiga.programmer:1740 Newsgroups: comp.sys.amiga.audio,comp.sys.amiga.programmer Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!lavaca.uh.edu!menudo.uh.edu!sugar!karl From: karl@sugar.hackercorp.com (Karl Lehenbauer) Subject: Re: 14-bit audio possible with the Amiga Message-ID: <1991Mar24.221516.5888@sugar.hackercorp.com> Organization: Sugar Land Unix -- Houston, TX References: Date: Sun, 24 Mar 1991 22:15:16 GMT In article mykes@sega0.SF-Bay.ORG (Mike Schwartz) writes: >Since the Amiga audio hardware has an 8-bit DAC plus 6 bits of volume >for each audio voice, it should be trivial to play 14-bit samples. Using >Audio interrupts, you can feed audio data and volume right to the DACs >(it would use a lot of CPU on a 68000). Using another feature of the >hardware, you can have the output of one channel modulate the volume of >another. So it looks like you can use DMA to do 2 channels of 14-bit >sound. Yes, it is possible and Soundscape does it. However, I wouldn't call it 14-bit because, unless you pretty much dedicate the CPU to the job, no arbitrary sample could have an arbitrary 14-bit value. I would call this 8-bit companded, like the Emulator II has. The way to do it, then, is to subdivide the sample into parts, calculate the RMS level of each subpart, figure out a 6-bit volume level, then scale the samples to be full-scale 8-bit. I looked into doing this for my SMUS and MIDI players, but haven't done so yet and am now not too likely to. You'll also need a 14-bit or greater sampling source. I use a Casio FZ-1 16-bit sampling synth, download the samples at full 16-bit resolution over MIDI to the Amiga, then downsample. The piano and bass included in my recently posted SMUS player were created in this manner, and I think you'll agree if you listen to them (with the filter off) that they are pushing the state of the art in Amiga sounds played only on the built-in hardware. -- -- uunet!sugar!karl Keeping 255 messages and deleting 158. --