Originally Posted by Free
Good memory Charles!!
Yes, that was me, and D-Box is more than just vibration, it is motion that is synchronized with the movies, in the same way that the movie score is created, so each movie has a motion code.
I went back through some of our old correspondence. I believe at that time, the D-Box was called the Odyssee. It turns out that the problem you were having at that time was that the Odyssee wasn't working because of a bad XLR-RCA adapter to get the S/PDIF signal to the controller box.
But then there was another problem. With some SuperBit discs (remember those???) there was a popping noise with your Lexicon MC12 during the disc's menu. It happened with the Ayre DVD player, your Panasonic D-VHS player, and even your Tivo box from time-to-time.
We never solved that at the time, but I still have the e-mails where the guys from Lexicon were giving you the run-around even back then. (I guess some things never change...)
You were the only one who had that problem, so we ignored it at the time because it also happened with other sources. We figured it must have been the Lexicon. Years later, we had more problems with an Arcam SSP that was very popular and did the same thing.
So we did our usual investigation and found out that the problem was the Dolby spec. Dolby sends out their data in "packets" and each packet has a header saying how long the packet is supposed to be. It turned out that the SuperBit discs violated this structure, but only with the sound effects in the menu.
The Dolby spec never said how the MPEG decoder in the DVD player was supposed to handle these bad packets, and it never said how the decoder in the SSP was supposed to handle these bad packets. The result was a popping noise (a *loud* one!) during the menu of improperly authored discs.
Lexicon wouldn't (or couldn't) change their firmware. Arcam wouldn't (or couldn't) change their firmware. Pioneer couldn't help us because the decoder we were using was discontinued (they changed models every year).
So we ended up writing a special program in our FPGA. It would monitor the audio signal. If there was a Dolby Digital ID in the header, we would then look at the length of the packet. If the packet length matched, we would let it through. If it didn't we would mute the digital audio output. Problem solved.
This was easy to implement on the DX-7 as it only required a firmware change. But the D-1 didn't have an FPGA! So we made a daughterboard and added an FPGA to monitor the audio signal and look for bad packets.
Roger, if you're still reading this thread, you'll understand some of the reasons why I still cringe when I hear the words "Dolby Digital". That was a lot of work for a small company like us. But we were the ones who solved it. Not the authoring company that made the defective disc. Not Lexicon. Not Arcam. But Ayre. At that time we had two engineers -- me and one other guy. It was a pain in the ass. But we did it -- somebody had to.
In all fairness, we couldn't have solved the problem without Dolby's help. They were actually unbelievably great about the whole thing. They analyzed the disc. They found the problem. They tried to get Pioneer to fix it. They bent over backwards and had tools and equipment to trace down the problem. They never charged us a dime. Things went kind of slow, but that's always the way it is with big corporations.
The bottom line is that there was never any problem connecting to the D-Box, except for a bad XLR-RCA adapter. It was the disc authoring problem that had you eventually sell the DX-7, even though it had the best picture you had seen....