From mailserv@gaia.ucs.orst.edu Tue Apr 26 18:37:57 1994
Precedence: Bulk
Date: Tue Apr 26 16:31:21 PDT 1994
From: gus-sdk-request@gaia.ucs.orst.edu (GUS Programmer's Server)
Reply-To: gus-sdk@gaia.ucs.orst.edu (GUS Programmer's Digest)
Subject: GUS Programmer's Digest V10 #17

GUS Programmer's Digest     Tue, 26 Apr 94 16:31 PST     Volume 10: Issue  17 

Today's Topics:
                    Maximum Entropy Deconvolution
                  Rev 2.4 vs. rev 3.7 - MIDI clicks
                               Subject:
              That hi-falutin <g>astronomical technique

Standard Info:
	- Meta-info about the GUS can be found at the end of the Digest.
	- Before you ask a question, please READ THE FAQ.

----------------------------------------------------------------------

Date: Mon, 25 Apr 1994 19:03:01 -0700 (MST)
From: Oscar M Fowler <oscar@cs.arizona.edu>
Subject: Re: Maximum Entropy Deconvolution

> I am wondering if anyone has thought of doing this to sampled sounds, to
> improve the signal to noise ratio.  Any thoughts?

I've been wondering about this sort of thing myself lately, but I'm not
really familiar with any of the math logic that goes behind this sort of
manipulation.  If anyone has more detailed info, I'd love to hear it.
Otherwise, I guess I'll have to get myself to the library and find some
books on sound processing...

omf

------------------------------

Date: Mon, 25 Apr 1994 22:53:13 -0400 (EDT)
From: mikebat@netcom.com (Mike Batchelor)
Subject: Rev 2.4 vs. rev 3.7 - MIDI clicks

I have several new rev 3.7 boards at work, and my own rev 2.4 board at
home.  First thing I noticed with the new boards is clicking at the start
of some notes on several different MIDI files, including the ones that
were bundled with the GUS.

Well, I've had a chance to compare against the rev 2.4 board I have had
for more than a year, and I cannot get it to click like that at all.  Not
on my home PC, and not on my work PC where I first heard the clicking with
the rev 3.7 board.  To top it all off, I put in a rev 3.7 board in my home
PC, and the clicking is here, too.  It happens with both the old Playmidi,
the new Playmidi, and Media Player under Windows.

On my work PC, I seem to have removed most of the clicks by going to
220,1,3,7,7, but they still are heard in some MIDI songs.  I haven't yet
gotten rid of them on my home PC, at the same settings, and also at my
usual 220,7,1,7,5.

Has anyone else heard this clicking at the start of notes?  What is the
solution?  If you care to, I have put easy.zip on netcom2.netcom.com in
/pub/mikebat, and if I play this one on a rev 3.7 GUS, it always clicks
somewhere, no matter what I do.  Easy.mid is an MT32 MIDI with CFG file
mt32pat.cfg, and uses log volume.  Playing it with linear volume has no
effect on the clicking.  Dumping the easy.cfg makes them go away, but the
patches are not the same: fretless becomes xylophone or something like it. 
And not every song that uses fretless has clicking problems.

-- 
Mike Batchelor      | UseLinuxUseLinuxUseLinuxUseLinuxUseLinuxUseLinuxUseLinux
mikebat@netcom.com  | xuniLesUxuniLesUxuniLesUxuniLesUxuniLesUxuniLesUxuniLesU
 -----------------------------------------------------------------------------
Plug 'N' Play:  A specification invented by Microsoft and Intel which
enables a computer and its operating system to create hardware conflicts
without user intervention.

No more jumpers to misplace!  The computer will misplace them for you.

------------------------------

Date: Tue, 26 Apr 1994 06:40:22 -0700 (PDT)
From: Seth Delackner <dax@crl.com>
Subject: Subject:

Change my E-mail addr. to dax@netcom.com please.
Thanks!

------------------------------

Date: Tue, 26 Apr 1994 10:08:29 -0700 (MST)
From: "Shawn T. Rutledge" <rutledge@enuxsa.eas.asu.edu>
Subject: That hi-falutin <g>astronomical technique

> Date: Sat, 23 Apr 1994 22:43:05 -0400 (EDT)
> From: mikebat@netcom.com (Mike Batchelor)
> Subject: Maximum Entropy Deconvolution
> 
> As an amateur astronomer, I am aware of a mathematical technique used for
> image processing called Maximum Entropy Deconvolution.  Several programs
> are available commercially that will perform this process on image data
> collected from CCD cameras, and it is used to improve the signal to noise
> ratio of CCD images, rendering visible hidden details.
> 
> I am wondering if anyone has thought of doing this to sampled sounds, to
> improve the signal to noise ratio.  Any thoughts?

Oooh!  Oh!  Tell me more!  Hadn't heard of the technique but it sure sounds
interesting.  What I don't get is how do you measure "entropy" in the picture,
and do you find pixels that are below a threshold (set how?) and then
perform a deconvolution on them?  A deconvolution with what?  Lessee,
the product of two fourier transforms is the convolution of the two
original functions, so to "de-convolve" you must have to take the fourier
transform and then divide or factor out something which you suspect might
have been the other original function, in order to recover the function
that you want.  Am I warm?


-- 
  _______                                                             KB7PWD
 (_  | |_)                                            shawn.rutledge@asu.edu
 __) | | \__________________________________________________________________
* fusion * sci fi * ARS * cyberspace * Interpedia * virtual reality * 

------------------------------

End of GUS Programmer's Digest V10 #17
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