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From: h112706@assari.tut.fi (Herranen Henrik)
Newsgroups: comp.sys.amiga
Subject: Re: CD sound (was Re: For all you who want more advertizing)
Message-ID: <1990Oct25.102443.5556@assari.tut.fi>
Date: 25 Oct 90 10:24:43 GMT
References: <901023.160924.CDT.C503719@UMCVMB.MISSOURI.EDU> <1990Oct23.215703.1586@cunixf.cc.columbia.edu> <1990Oct25.003358.24989@dg-rtp.dg.com>
Organization: Tampere University of Technology
Lines: 52


In article <1990Oct25.003358.24989@dg-rtp.dg.com> poirier@ellerbe.rtp.dg.com (Charles Poirier) writes:
>I'm not flaming, either the poster or the Amiga sound capability, but the
>phrase "compares favorably to CD" is definitely not what I would favor.  "Is
>kind of okay, considering the limited CHIP bus bandwidth" is more like it.
>To say that Amiga's 8-bit audio is comparable to CD sound (it doesn't matter
>*how* carefully it is digitized into 8 bits) is to say that one has a tin
>ear.

True.

>Eight bit sound is audibly noisy (to me).  Sound that rolls off at 7 KHz
>(with the filter on), sounds like it is coming from under a pillow.  Sound
>that rolls off at 14 KHz (with the filter off), is better, but it still
>sounds like it's coming from under a towel, while simultaneously wind
>whistles through a crack in a nearby window (aliasing).  I may have the
>numbers wrong, but not the perceptible results.  Also: most CDs play more
>than four simultaneous notes/voices :-) !  Amiga sound is not even close to
>CD quality.

Here goes... This is also not meant to be a FLAME to anyone, I just want
to express my thoughts about the Amiga sound.

The limited bandwidth of Amiga is one thing that makes Amiga sound inferior
to CD sound (28 kHz max. vs. 44.1 kHz). Professional samplers use to have
sample playback rates up to 100 kHz, which makes the sound quality much
better becouse if you use the same sample for a whole octave, the lowest
playback rate is still 50 kHz (more than enough).
   The other thing, 8 bit sound, is a problem especially becouse no
compression method is used. It is possible to get a 90 dB signal to noise
ratio with 8 bits with compression although the sound will not be
as good as true 16 bit sound is.
  And, how about the pitch control (no-one has mentioned it, I think)? When
played with high sample rates the resolution of sound pitch control degrades.
The difference between nearest two sounds you can create is almost 1%, which
is far too much to get a pure tone. If the sample rate was being doubled,
it would be a must to get some more bits to sample playback speed control.

BTW Charles, you said that "most CDs play more than 4 simultaneous
notes/voices"... Actually, CDs have only 2 voice generators/DA convertors
as opposed to Amiga's 4. If I would sample an orchestra sound to my Amy,
it could play all the 40 instruments of the sample simultaneously B-)

>	Cheers,
>	Charles Poirier  poirier@dg-rtp.dg.com

Henrik 'Leopold' Herranen  Internet: h112706@lehtori.tut.fi
Snail Mail:  TTKK/Paarakennuksen neuvonta/PL527/33101 Tampere/Finland
-- 
Henrik 'Leopold' Herranen  Internet: h112706@lehtori.tut.fi
Snail Mail:  TTKK/Paarakennuksen neuvonta/PL527/33101 Tampere/Finland

"I don't need no arms around me, I don't need no drugs to calm me" - PF 1979