"Record output of Sonic Hologram process, for playback in my car" project brief status update:
(1) Phase 1 complete (not without some issues to overcome, see below). WAV file recorded on PC, and then burned to CD for playback in my car.
Although my car does not have a USB/SD digital input to its media system, it does have a CD player which obviously is just as good. So while I certainly could create a FLAC file from the WAV and then write it to my Cowon J3 player for "analog" playback in my car from the J3's headphone jack into the car's AUX 3.5mm stereo input, I decided I might as well just use a physical CD as yet one more alternative "digital" format (of the WAV master) instead of the unavailable USB drive or SD flash card. Really shouldn't make any difference in seeing what "recorded sonic hologram" sounds like played in my car, since the FLAC file is digitally identical to the WAV->CD anyway. So it's just a matter of which "player" and DAC is utilized to go from digital to analog for listening. I don't think this should have any effect on the "3D illusion" I'm interested in experiencing.
Tomorrow I will actually play it in my car, along with the original "master" CD. Subjective evaluation and comments to follow.
(2) I ran into an immediate MAJOR problem after getting all of the cabling done, to connect the RCA preamp output (of my T2) into the line-in of my PC's sound card. When I activated "listen to this RECORD device on default PLAYBACK device" when setting line-in as the source, there resulted a very severe 120hz ground loop hum. There is no hum when I "listen" to the microphone (plugged into mic-in of the sound card). But this line-in (RCA cable) coming from outside the PC, i.e. from my audio system, well the RCA cable connection of the two systems obviously has introduced this very bad hum.
Fortunately, I had actually faced (and solved) this very same issue back a year or two ago when I hired Lorr Kramer to render a PRIR measurement in my car, using my A8. We staged the activity in a building garage that had an available power outlet, but once again there was an RCA cable connection from the A8 to the AUX input of the car. And that produced the very same type of hum I experienced tonight connecting my audio system to my PC via RCA cable.
The solution back then (and once again tonight) was to "break" the electrical connection facilitated by the RCA cable which was responsible for the ground loop, while still facilitating the passage of the audio signal. And the trick was to use an analog-to-digital converter fed via RCA-input from the source device, which was then connected via optical cable to a digital-to-analog converter, which then fed RCA-output to the target device. The net result is to have the audio signal "fly through the air via optical, not via copper", thus passing "data" but not involving electricity... and thus eliminating the possibility of a ground loop.
Did the same thing tonight to connnect the RCA output of my T2 preamp to the RCA input of my PC, going through the ADC (on the left in the photo below) and then to the DAC (in the center of the photo below). Each of these gizmos is 5v-powered through a USB cable, like a phone charger or in my case I have a power strip with multiple USB ports for charging (on the right of the photo below):
(3) I had really wanted to create six individual "tracks" on the CD, as there truly are Parts 1-6 on the original CD. Unfortunately there really is no discrete break (or silence) between each "part". They just run consecutively, with one part suddenly becoming the next part without a clear separation.
So I just could not create six discrete "tracks" as I intended. I don't really care, though, for the purpose of this project. So I just created the CD with one large 39 minute "track". Not any type of real problem, and certainly has zero effect on playback in the car and what I will subjectively conclude.
(4) I always put a sticky CD label on any CD I burn, and so I scanned the original CD and duplicated its artwork onto my own printed label. And then I went to print it on my Canon Pixma 9000 II photo printer (which hadn't been used for several months). And naturally, 3 of the 8 ink tanks (R, G, and PM) needed to be replaced!! That's how they make money (at about $20 per tank). R and G last a relatively long time. PM gets used up very quickly in quality photo printing. So it cost me $60 just to be able print this one stupid CD label.
==> Nevertheless, Phase 1 is now complete. The proof is in the pudding, so we shall see how it tastes.