I'm not sure about that particular DBX unit but I used a four channel DBX Type One Pro (4 channels) with an old Teac 3440 years ago. On certain things it did great and on others (especially bass guitar) it pumped and breathed like crazy. That was long ago though and from what I understand DBX NR is much improved now.
I don't know a thing about the Tascam unit. How does it work? The best alternative to DBX (as far as I know) is Dolby A or SR or both. Even so, I'd settle for Dolby C before I'd take on an old DBX unit again. As far as I know however, no multi-channel Dolby C units exist. The MKIII is eight track isn't it? Boy, its been so long I just don't remember anymore. I would think it's got around a 70 DB S/N ratio at 30 inches per second. That's good enough to go sans NR in my opinion. That outboard NR gets darn expensive. Back when I had my DBX unit, it was around $200 per channel even then. I don't even want to think about what Dolby A costs!
