dillon@ucbvax.BERKELEY.EDU (Matt Dillon) (12/12/85)
Well, considering you specify sound in a 256-level range, I would assume it's an 8-bit DAC. Considering that a 5-bit DAC is plenty good enough for voice and most sound synthesis, an 8-bit DAC should be out of this world. (I havent gotten my hardware manual yet). Hmm.. yes, well, when I put the Amiga in 640x200x2 mode, sound works fine. As soon as it goes into 640x200x4 mode, however, the video chip eats up all the time and the sound chip only gets it during retrace (I think). ------ I sent Commodore a check, and have yet to receive my books & software (However, it has only been 2-weeks). I hope they don't take too long to validate my check, I kinda can't do anything with my Amiga until I get that stuff (except program in.... (Yuc) Basic). -Matt
tre@sdcarl.UUCP (Tom Erbe) (12/13/85)
In article <11217@ucbvax.BERKELEY.EDU> dillon@ucbvax.BERKELEY.EDU (Matt Dillon) writes: > > Well, considering you specify sound in a 256-level range, I would >assume it's an 8-bit DAC. Considering that a 5-bit DAC is plenty good >enough for voice and most sound synthesis, an 8-bit DAC should be out of >this world. (I havent gotten my hardware manual yet). Listening to an 8-bit DAC is like playing your stereo through a fuzz box. It may be okay for games and demos, but any serious sound work should be done with at least 12-bits (16 or more preferred). Perhaps the Amiga needs an outboard sound box. -- thomas r. erbe {ucbvax,ihnp4,akgua,hplabs,sdcsvax}!sdcarl!tre
hes@ecsvax.UUCP (Henry Schaffer) (12/14/85)
> > Well, considering you specify sound in a 256-level range, I would > assume it's an 8-bit DAC. Considering that a 5-bit DAC is plenty good ^^^^^^^^^^^^^^^^^^^^^^^^ > enough for voice and most sound synthesis, an 8-bit DAC should be out of > this world. > > -Matt If you said 15 bits, I certainly would agree. On the last point, an 8-bit DAC should be out of this word for musical sound synthesis, but we have to specify which direction :-). --henry schaffer
gibson@unc.UUCP (Bill Gibson) (12/15/85)
>> assume it's an 8-bit DAC. Considering that a 5-bit DAC is plenty good > ^^^^^^^^^^^^^^^^^^^^^^^^ >> enough for voice and most sound synthesis, an 8-bit DAC should be out of >> this world. >> -Matt > If you said 15 bits, I certainly would agree. On the last point, >an 8-bit DAC should be out of this word for musical sound synthesis, >but we have to specify which direction :-). >--henry schaffer Total agreement. 8 bits is *minimal* sound quality for synthesis; 8 bits of sampled sound gives you a 48 dB signal-to-noise ratio. That's about as good as a bad tape recording. Not to mention that the Amiga's output contains only frequencies below 5 kHz, an *extremely* low limit. I suppose that this is the result of an engineering tradeoff so that the sound hardware can use a standard video rate for writing out samples; the machine apparently wasn't targeted at the music marketplace. That's too bad, since a higher sampling rate could have been used easily, with the major drawback that more memory would be used per time unit. Bill Gibson
atoy@watnot.UUCP (Andy Toy) (12/15/85)
In article <918@ecsvax.UUCP> hes@ecsvax.UUCP (Henry Schaffer) writes: >> >> Well, considering you specify sound in a 256-level range, I would >> assume it's an 8-bit DAC. Considering that a 5-bit DAC is plenty good > ^^^^^^^^^^^^^^^^^^^^^^^^ >> enough for voice and most sound synthesis, an 8-bit DAC should be out of >> this world. >> -Matt > If you said 15 bits, I certainly would agree. On the last point, >an 8-bit DAC should be out of this word for musical sound synthesis, >but we have to specify which direction :-). I've heard digital audio from an 8-bit DAC and it sounded GREAT. You could limit down to it 5 or 4 bits and it would still sound good. The demo I heard used a Billy Joel compact disc going through a 10-bit DAC that had the capability of switching off as many bits as you wanted. You could still hear that it was Billy Joel even with 3 bits, but it was not as good. When dither was added, it sounded as good as it did with 5 or 6 bits although there was some noise added. It would be fantastic if you could get the Amiga to play digital music if it had enough memory (or at least a fast CD drive). --- Andy Toy Mapping Analysis and Design Group, University of Waterloo, Waterloo, Ontario, CANADA, N2L 3G1 UUCP: ...!{utzoo|decvax|ihnp4|clyde|allegra|linus}!watmath!watnot!atoy ARPA: atoy%watnot%watmath%waterloo.csnet@csnet-relay.arpa CSNET: atoy%watnot%watmath@waterloo.CSNET BITNET: atoy at watdcsu
mjg@ecsvax.UUCP (Michael Gingell) (12/16/85)
SOme people have complained that the Amiga only has an 8 bit DAC (D/A COnverter) but, as I understand it, it also has a 4 bit gain control - this gives a significan increase in dynamic range. Mike Gingell ....decvax!mcnc!ecsvax!mjg
keithd@cadovax.UUCP (Keith Doyle) (12/18/85)
In article <270@sdcarl.UUCP> tre@sdcarl.UUCP (Tom Erbe) writes: > > Listening to an 8-bit DAC is like playing your stereo through a >fuzz box. It may be okay for games and demos, but any serious sound work >should be done with at least 12-bits (16 or more preferred). Perhaps the >Amiga needs an outboard sound box. > > thomas r. erbe Wellllll, yes and no. I've done a lot of playing around with an 8-bit A/D D/A for this sort of thing for some time, and find that it all depends on what you're doing. Sampling frequency seems to have a more detrimental effect if it's too low than using 8 bit dacs. Filtered output sure helps. Sure, playing your stereo thru an 8 bit dac would sound pretty terrible, there is not enough dynamic range really, the loud parts would probably be tolerable, but the soft parts would sound like a fuzz box. For sound sampling for synthesizers though, lots of dynamic range may not be quite as important. Note that the Ensonique Mirage is a commercialy available sampling synth ($1695 U.S.) that uses 8-bit, though they may be using companding or something, I'm not sure. One thing that helped my experiments, is that I was using an analog synthesizer for volume envelope control over a digitally sampled sound that was always being output at full volume. This probably had the effect of masking some of the dynamic range problems of using a system where the DAC is used to do the volume variances too. Still, an 8-bit DAC is better than a 4-bit DAC which is better than no DAC at all. Especially an 8-bit DAC that dosen't require you to dedicate large CPU resources to keep the sound going. The Amiga dosen't need an outboard sound box as much as the Mac, the Atari, and the P.C. do by a far cry. Keith Doyle # {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithd # cadovax!keithd@ucla-locus.arpa