Hello S T Riddle,
Thank you so much for the wonderful work you have done on your multi matrix decoder. This is truly an exciting development.
This is my first time posting to any QQ thread since I joined the group a few years ago. I am rather surprised about the small activity on this thread, so I've decided to answer your call for suggestions.
First a little about myself, I am a retired former IT professional from business processing. I have no scientific programming experience in DSP. Also, I have no experience in the recording industry. I became interest in the surround sound technologies in the early 70s and have been following the development of these technologies since. I have listening experience with several of the components described on this forum including the Tate II and lately the Surround Master. I also have experience with the Adobe Audition scripts. Like you, I have been intrigued by the ideas of Lynn Olsen and have read through the original patent papers for this technology long ago.
Let me walk you through the results of a couple of tests I have completed with your decoder. First of all I have obtained the SQ and QS Test Tones from the website...
http://www.quadraphonic.info/SQandQS/
and after learning the basics of the Plogue Bidule platform, have processed the test tones through your decoder. I am assuming that these tones are accurate as is claimed on the website.
The first test was of your version of QS Vario Matrix. The results are shown from the screen print using Audacity.
The test shows the signal processed through 8 points of the circle. Viewing from left to right the test tone is decoded for CF, LF, LS, LB, CB, RB, RS, RF, and finally returning to CF. I did not change any parameters, which you can adjust, but used the default settings. The channels shown from top to bottom are LF, RF, LB, and RB.
Some wonderful things are happening here.
1. CF power is reduced to around .707 , that magic number, in each of the LF and RF channels. There is no crosstalk in the rear channels.
2. LF is completely isolated at full power.
3. LS is shown at a reduced power level with some cross-talk to the channels of the right side.
4. LB is completely isolated.
5. CB is shown at the reduced power level with no crosstalk to the front channels.
6. RB is completely isolated.
7. RS is shown at a reduced power level with some crosstalk to the channels of the left side.
8. RF is completely isolated.
9. CF is shown similar to its original description (see number 1 above).
Bravo. This was only one test and involved no listening on my part. I know from other listings on this forum, that the phase of the output is also important in establishing a clean image. I have no knowledge on how to test that. Perhaps one the other readers will step forward.
I would hope to see similar results for the SQ test. A screen print for that test follows.
First I would like to draw your attention to the fact that the test tones travel in the following order: CF, RF, RS, RB, CB, LB, LS, LF and finally CF again. (Note this is the opposite direction from the QS example)
You have produced a fine start for the SQ shadow vector. Again I used the default settings for the parameters in your component. Here are some comments.
1. CF is produced at full power in both the left and right channels. It needs to be reduced to the .707 is each channel.
2. RF is full power with little crosstalk, excellent!
3. RS test tone is produced reduced (to .707?) in the RF channel, however the RB is still at full power and also needs to be reduced to .707.
4. RB is full power with little crosstalk, excellent!
5. CB is produced at .707 power in both LB and RB channels, excellent!
6. LB is full power with little crosstalk, excellent!
7. LS test tone is produced reduced (to .707?) in the LF channel, however the LB is still at full power and also needs to be reduced to .707.
8. LF is full power with little crosstalk, excellent!
9. CF is produced at full power in both the left and right channels. It needs to be reduced to the .707 is each channel.
All in all, an excellent effort. You are well on your way to a fantastic implementation. There have been many theories and products tackling this idea and are you are providing an excellent solution. Of course a lot of further testing is desired. Together with the insight of others, I know you will conquer this dream. Thank you.