I vote Dragon.
BTW 76Doublebass, you're confusing dbx's expanders (1bx, 3bx, 5bx, etc) with its companding noise reduction system for recording. The former were single ended and intended to enhance/restore dynamics to existing material. The latter were designed for tape noise reduction and used an encode function on record followed by a decode function on playback. They are entirely different classes of product.
dbx noise reduction used brute force 2:1 compression on the encode side followed by 1:2 expansion on playback. It is a constant slope system and did not really require calibration to the tape, unlike Dolby B,C, and S.
The Dolby NR schemes did little processing when the signal level on tape was above a predefined point (the Dolby level - look for the double D symbol on the cassette deck level meter), and performed most processing on signals below that level. That also meant that if playback levels did not match record levels exactly, the Dolby system would mistrack. This made pre-recording tape calibration and playback azimuth alignment especially critical.
dbx simply applied constant compression/expansion to the signal without regard to level. As others mentioned, that made the signal unlistenable without dbx decoding.
BTW 76Doublebass, you're confusing dbx's expanders (1bx, 3bx, 5bx, etc) with its companding noise reduction system for recording. The former were single ended and intended to enhance/restore dynamics to existing material. The latter were designed for tape noise reduction and used an encode function on record followed by a decode function on playback. They are entirely different classes of product.
dbx noise reduction used brute force 2:1 compression on the encode side followed by 1:2 expansion on playback. It is a constant slope system and did not really require calibration to the tape, unlike Dolby B,C, and S.
The Dolby NR schemes did little processing when the signal level on tape was above a predefined point (the Dolby level - look for the double D symbol on the cassette deck level meter), and performed most processing on signals below that level. That also meant that if playback levels did not match record levels exactly, the Dolby system would mistrack. This made pre-recording tape calibration and playback azimuth alignment especially critical.
dbx simply applied constant compression/expansion to the signal without regard to level. As others mentioned, that made the signal unlistenable without dbx decoding.