[Trlog] SBDVP - Arrrrrrrrg

[Kevin Schmidt]

Pete,

The Soundblaster pro had a set of fixed rates that are given in Hz by
1000000/x where x is an integer between about 40 and 250. SBDVP uses
that method to set the rate. The Soundblaster 16 and other cards can
use this same method, but also have alternative methods that allow a
much wider range of rates. SBDVP does not use the fancier methods. The
only time you will see a rate different from the default 12048 Hz is if
you use the -r command line switch to change it.

73 Kevin w9cf

> Date: Thu, 13 Mar 2003 08:03:59 -0500
> To: kk1l at arrl.net, K4BEV at aol.com
> From: Pete Smith <n4zr at contesting.com>
> Subject: Re: [Trlog] SBDVP - Arrrrrrrrg
> 
> At 11:34 PM 3/12/03 -0500, Ronald Rossi wrote:
> 
> >I have been doing a little bit of research and found reference to the
> >sample rate being set differently between SB16 and other cards. The rate
> >in SBDVP is set using a timeconstant related to the sample rate in Hz.
> >The SB16 is set using the sample rate. Is is possible this may be partly
> >to blame? It also appears that the rate is set independently for play
> >and record. I could not see where this was covered in the SBDVP source.
> >
> >Pete or Don, Maybe you could check to see what the sample rate of the
> >recorded file is when you play it with GoldWave or whatever.
> 
> I have checked a number of files recorded through TR and SBDVP with 
> Goldwave, and find they sound natural at 12K or thereabouts.  When I start 
> either an ISA or a PCI SB16, I get the following report in the DOS window:
> 
> C:\LOG\CONTESTS\03\Test>sbdvp
> program sbdvp Version 1.0.3
>   IRQ = 5
>   BASEIO = 220
>   DMA = 1
>   SBTYPE = 6
> CQF10.DVP opened 46000 bytes
> nearest rate is 12048 Hz
> Attempting reset of sound card
> Successful
> 
> Does the "nearest rate" information mean that SBDVP has found that the 
> sound card has a number of preset rates, and has chosen the one closest to 
> its optimum?
> 
> 
> 73, Pete N4ZR
=-------------------------------------------------------------
Kevin Schmidt, w9cf at ptolemy.la.asu.edu, http://fermi.la.asu.edu/w9cf
Department of Physics and Astronomy
Arizona State University, Tempe, AZ 85287-1504
(480) 965-8240 Fax: (480) 965-7954