The ADS C3 cassette deck can play at the standard 1 7/8 IPS, but also at 3 3/4. The double speed mode increases performance, including: noise floor, wow and flutter, and high frequency reproduction. At single speed the deck already performs very well, but the quality at double speed puts this deck in contention for the highest quality to be had from cassette. It even approaches the reel format, with the noise floor and wow/flutter being the only specs really holding it back (while still being very good for cassette). Lucky for us, those faults don’t exist in the Nebula programs! Many tapes were used, with some of each type (I, II, III, and IV), and of various qualities.
Most were sampled twice, usually with the first time being done in a way to get the best representation of that tape with this deck, and the second time to produce a ‘less perfect’ result. Double and single speed modes were used. Dolby B and C were used, but in some cases neither. The deck requires the user to manually select the EQ mode for the type of tape being used, and often the ‘wrong’ type was intentionally selected, to get different tonal results. This set has a large variety of sounds. Altogether there are 31 unique effects, each in 5k and 10k options!
Some of these effects are fairly flat across the frequency spectrum, extending beyond 20khz, and down below 20hz! Those can be used as you would use a reel to reel program, for a subtle tape effect. Others have an upwards incline in the high end, making them fairly bright. Those can be used as enhancers. The high-end boost and the added tape saturation can be very useful for making something seem louder (and more defined) than it really is. Then you have others which smoothly filter highs or mids in various ways.