DBX Type II and Cassettes

[braxus]

I received my second Aiwa XK-009 deck last April. (I sold the first one in 2006). Anyway I had to try it out to make sure all is well. I noticed this deck picks up hum from nearby speakers or components that other decks seem to isolate. No matter. I decided to try out a recording on DBX since I never did give that noise reduction system a listen, having used all the Dolby variants over the years. Today I stick with Dolby S. But the XK-009 was before Dolby S came out, so it was designed with DBX as its premiere NR. So I plunked in a Denon DX-4 tape and a Carpenters SACD. I set the bias after figuring out how to do so on this deck. Its a little different in function then my Sony, as certain buttons have to be engaged to work. Anyway I got the bias down pat and was off to recording. Put a couple songs I knew well from the Carpenters SACD. Started to record. I was surprised with DBX how well the voice presentation was kept from the disc being recorded. It wasn't at all compressed sounding, as I've heard stories of how DBX can suck the life out of the recording. Didn't seem to be the case here. I wasn't sure if I heard some slight pumping in quieter parts of the song as it was ending. I didn't compare it to the source to know for sure. It was slight though. It could also be my imagination. All I know is the recording on a couple songs sounded quite full of life and stayed true to the source better then I expected. I had the meter with this normal bias tape and DBX pegged to plus 10db. Some moments it went to 12db and a couple times as far as 14DB. It didn't sound distorted one bit. If this was Dolby, I doubt it would go as high. I do know the DX-4 tape can handle a lot of signal, since it is a high end normal bias tape. One last test was to listen to the tape while recording dead silence. I cranked the preamp volume to full maximum. I heard some slight hiss which I wasn't expecting. I'd thought with a deck with DBX advertised with 95db signal to noise, I shouldn't hear any hiss. But to be fair I switched it over to Dolby C, then B, then off. The hiss with C engaged quadrupled over DBX and off was quite hissy. So DBX does work- just not miracles. I'll still stick with Dolby S since that is compatible with other decks and I have two decks that use it. But using DBX was fun to try and I now know what its like using it. DBX was the reason I got the XK-009 deck, in case I'd need to use that NR in the future for other peoples tapes. With Dolby C the XK-009 deck sounded pretty good- as good as any other deck I've heard. Below is a pic of the deck I just got. You can also see the American DJ DB display I also just got sitting on top of the deck. That piece is too wide to fit inside my current rack. I am designing a new rack to fit all these stereo pieces I can't all fit in the one rack I currently have. I keep having to swap out decks to use them in my system. My 8 track is now sitting unplugged on another shelf in the room. Anyone have any idea which car decks used DBX in them? I suspect they were from the early mid 80s.

Also is it true DBX tapes must be recorded with lower levels then with Dolby? I would have thought that the higher compression DBX uses would allow a stronger signal to be put onto the tape. Again I successfully recorded up to 14db on my one tape with DBX, but I'm told not to do this?