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From: clemon@lemsys.UUCP (Craig Lemon)
Newsgroups: comp.sys.amiga.audio
Subject: Re: Disable low-pass filter on Amiga 500?
Message-ID: <7751.669842709@lemsys.UUCP>
Date: 24 Mar 91 19:25:09 GMT
Article-I.D.: lemsys.7751.669842709
Followup-To: comp.sys.amiga.audio
Lines: 28
In-Reply-To: ags@scs.carleton.ca (Alexander George Morison Smith)

In a message posted on Thu, 21 Mar 1991 20:19:50 GMT,
ags@scs.carleton.ca (Alexander George Morison Smith) wrote:
AGMS>The Amiga audio filter cuts off at 7KHz, I believe.  So it is still
AGMS>worthwhile to disable it.  Besides that, the sampling rate has to be
AGMS>twice the frequency if you want to reproduce sounds of a given
AGMS>frequency.  Even higher sampling rates improve the quality of the sound. 
AGMS>As you may know, compact disks are recorded at a rate of 14KHz. 
							      ^^^^^
AGMS>- Alex

	That's 44.1 kHz.  CDs are also oversampled anywhere from 2 to 256
times depending on your DAC.  There are also PWM/PDM (Pulse Width/Density)
conversion schemes as opposed to the traditional 8/12/16/18/20 bit DAC
chip.  A straight 44.1kHz Amiga sample will not sound as good as a CD
because of both the oversampling and number of bits resolution.  CDs have
12 bit resolution I believe (may be 16 but I don't think so).  The extra
bits in vertain DAC convertors are for internal interpolation done by
oversampling.  

I know this isn't totally Amiga relavent but this previous
post will probably lead to "My 14 kHz samples don't sound like CDs" and
"So if I use XXX sampler I can get CD quality audio" type posts.

--
 Craig Lemon - Kitchener, Ontario. Amiga B2000/10--UUCP 1.06D/Gnews v1.1/UUCP+
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