The GUS Programmer's Digest Thursday, 11 May 1995 Volume 19 : Number 004 Today's Topics: Hi out there? 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. ---------------------------------------------------------------------- From: Chris James Date: Thu, 11 May 1995 09:55:00 -0700 (PDT) Subject: Hi out there? Just wondered whether this mail group was read by anyone else? If it is then any opinions on these thoughts/experiences: Just got the V2.22 Gravis SDK, not much to say except that presumably _some_ problems are fixed (like the notable absence of documentation for some functions). For those that program the MAX and use C++ 9 (and I mean really write C++), you presumably have fixed a couple of header files for the codec support. I found they missed out the ending brackets for the extern "C" declarations (only noticed when you do a C++ compile) again. (The .h's are identical so I just use the old ones I fixed). Has anyone used the MAX's recording gain in Windows? That's the separate slider which is gain applied after the input to the recording multiplexer. I found that I start to get a significant DC offset in the signal when I use this. This also has happened when I've programmed the codec using the SDK in DOS, in the end I left out this gain control which is a bit of a shame. Having read the Codec data sheet I find there's a couple of things that could account for this problem. Firstly the codec is able to do some autocalibration which might just be designed to sort out DC problems amoungst other things. This calibration is done when one switches mode on the codec, which is for example between some coding options (say 16-bit PCM to ADPCM). It is possible to disable/enable this. So maybe its not enabled by the software. Even if it was this doesn't help if we only adjust the input gain, so it would be good to be able to force a re-calibrate before commencing recording in any event. I may have misunderstood what re-calibrate means in this case. The other possibility is that there is just some inherent DC generated inside the codec (all the gains are internal to the chip). If this is so then maybe it would be nice if we could activate the codec's digital high-pass filters, thus getting rid of any DC at all. Really these should be switched on all the time since this is a "sound" card we're talking about, not for general acquisition. Yet another option with the codec! Incidentally the codec can also manage full duplex on _one_ DMA channel! This may not be possible with the circuit set up on the MAX, in any case its not an option in the SDK. I would like to follow Gravis/Forte's advice and do some of my own level programming. This won't fix the Window's problem (unless I write a Windows driver, ughh! In my dreams) and in any case there's only so many days in a life. Otherwise the SDK is brill! My only other comment is, has anyone actually managed to get click free continuous (i.e. DD) output from the GF1 using the SDK? Following up Future Crew's hints on this is another project in my long list... Has anyone tried out these V4.11 drivers etc yet? yours, hopefully not mailing into a void Chris James ------------------------------ End of The GUS Programmer's Digest V19 #4 ***************************************** To post to tomorrow's digest: To (un)subscribe or get help: To contact a human (last resort): FTP Sites Archive Directories --------- ------------------- Main N.American Site: ftp.orst.edu pub/packages/gravis wuarchive.wustl.edu systems/ibmpc/ultrasound Main Asian Site: nctuccca.edu.tw PC/ultrasound Main European Site: src.doc.ic.ac.uk packages/ultrasound Main Australian Site: ftp.mpx.com.au /ultrasound/general /ultrasound/submit South African Site: ftp.sun.ac.za /pub/packages/ultrasound Submissions: archive.epas.utoronto.ca pub/pc/ultrasound/submit Newly Validated Files: archive.epas.utoronto.ca pub/pc/ultrasound Mirrors: garbo.uwasa.fi mirror/ultrasound ftp.st.nepean.uws.edu.au pc/ultrasound ftp.luth.se pub/msdos/ultrasound Gopher Sites Menu directory ------------ -------------- Main Site: src.doc.ic.ac.uk packages/ultrasound WWW Pages --------- Main Site: http://www.xmission.com/~grue/gus.html Main European Site: http://src.doc.ic.ac.uk/packages/ultrasound/ Main Australian Site: http://ftp.mpx.com.au/archive/ultrasound/general/ http://ftp.mpx.com.au/archive/ultrasound/submit/ http://ftp.mpx.com.au/gravis.html Mirrors: http://www.st.nepean.uws.edu.au/pub/pc/ultrasound/ GUS digest: http://gpu.srv.ualberta.ca/~itam/digest.html MailServer For Archive Access: Email to Email to New Submit Files Mailing List: Email to with content "subscribe epas-list " Hints: - Get the FAQ from the FTP sites or the request server. - Mail to for info about other GUS related mailing lists (general use, musician's, etc.).