[TRLog] SBDVP Problems

Kevin Schmidt w9cf@ptolemy.la.asu.edu
Wed, 27 Oct 1999 21:49:47 GMT

> Hello to the list,
>      I am new to TRLog and SBDVP.  I am unable to get good recordings of =
> audio from the TR program.  There seems to be insufficient volume.  I =
> have the mic level set to max and am using the -v option when starting =
> sbdvp.  Is there a way to record the needed files using the sound =
> recorder program in WIN98 and if so what format would I use?
>     TNX & 73's,
>         de Jim Harvey KC8LBH =20

Hi Jim,

Just for clarification, don't associate SBDVP with TR. Tree has been
very helpful, but any problems with SBDVP are mine and shouldn't
reflect on TRlog.

Some possibilities to check:

Can you get any sound at all? If not, you might try playing an audio
CD, etc. to see if the sound card mixer is set to one of the possible
inputs. The mixer stuff is not very standardized so SBDVP assumes it is
already set up properly when it is started. Play around with the sound
card mixer utilities if the wrong input is being used. Also you can
make sure the appropriate volume controls are turned up using the same
utilities.  If you are getting very low sound, check that the 20dB
preamp for the microphone is turned on using the sound card
utilities/operating system software. Often this is hidden away in
"advanced set up" or some other misleading menu item.

To convert from other audio formats is straightforward.

The file format for SBDVP is just a string of 8 bit bytes. 0 is most
negative voltage and 255 is most positive. This is called 8 bit
unsigned audio and any standard conversion utility will work to convert
from various other formats to 8 bit unsigned. Some recorder software
may be able to produce this directly as well, I don't know.

One way to convert is to use the DOS sox (sound exchange) utility
available at <http://www.spies.com/Sox/> The syntax is awful, but it
does work.  To convert the file temp.wav to cqf1.dvp,

sox -t wav temp.wav -r 12048 -u -b temp.raw
copy temp.raw cqf1.dvp

should work. This says an input wav file should be converted to a rate
of 12048 Hz, unsigned, bytes, and be called temp.raw.  Sox uses the
file extension, so it needs to be raw here. Then copy it into the file
you want and all should work. I'm sure there are many other such
utilities available.

73 Kevin w9cf
Kevin Schmidt, w9cf@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
(480) 965-7954 (FAX)

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