A?Question For Experts

[nestbox]

OK, I know my bit about analogue recording, its greatness and shortfalls, ~but would someone once and for all kindly tell this experienced 53 year old... is DAT and the rest, really any better than tape being scraped across metal? Is it? Do the portables, specifically, of the pre DAT age, not perform very well, and possibly sound better, regardless of the clinical, lab-based specs, compared to the 'new' mediums.

Please -kindly- post replies to me directly, as well as on the forum, as I don't always have time to review all fields here.

Many regards. Mark.

[Nakdoc]

Helical scan data vs. analog magnetic fields? If you think about it, analog tape is recorded bit by bit; each magnetic crystal is one bit.
All I can say is DAT sounds really good recorded at 48kHz, but has no headroom. Those of you who are Deadheads have heard the difference between DAT and analog showtapes. My problem with DAT is my lack of confidence that the heads will be available 5 years from now. DAT headwear is significant compared to analog. The good news is DAT tape seems to hold up just fine, which can't be said for reel and some cassette tape.

[Skywavebe]

Hi Mark,

Dat tape is to be abandoned first. Reel tape will probably still be around a decade or so. Sony stopped making DAT machines in 1997.
Dat tape is highly sensitive to minute pieces of dirt on the already too small drum and it's interchange is even more critical than formats like VHS, Beta and the Umatic. Anyone who uses DAT as a archiving medium is not doing anyone any favors. In a recent conversation with Richard Hess- and I think he knows his stuff, he said to me to get program material off DAT before dealing with all the reels we have in waiting. I think this says what is needed about this format. There is no format that does not touch the tape. The closest thing we have to non-physical touch is the hard drive and most know how much you can depend on those- especially a present day Seagate. The larger the packing density of bits on the platter the lower the reliability- this is talking real case not what some manufacturer states- he is not going to pay for your lost data- ask him.

[Wilhelm]

Much depends on the materials chosen for the production of the medium, the storage of the medium, and the handling. BASF vaults have a tape recorded in 1935 that still plays and sounds better today on modern heads than it did then. Since the backing material was cellulose acetate, it is very brittle and must be handled gently; but the recording is sound. Recordings made at speeds of at least 7.5 ips on basic open-reel tape with polyester backing ought to last for a very long time. The biggest problem with reel tape was the use of an unstable hydropscopic binder by Ampex and Agfa-Gevaert that gave tape a bad name. BASF, 3M, and EMI did not use that product in their formulations.

The same holds true for cassette tape, but the more sophisticated the pigment used, the more unstable it is over time. Metal particle is the most susceptible to chemical changes (including oxidation); high-bias Type II formulations are next. It is important to keep all these tapes in an environment free from large changes in temperature and humidity and from sources of sulphur.

Helically scanned tapes take a beating when they are played; but if the formulations take that into account, they are no worse than high-bias tapes in terms of stability. Since most have been used for FM modulated or digital signals, slight differences in output over time have no effect on the output, unlike analogue audio tapes with noise reduction. (A VHS tape in production testing had to sustain 60 minutes of of still frame playing with no increase in dropouts at that spot once the tape had cooled, according to the testing standards where I worked.)

The enormous jump in data recording density on hard drives is due to perpendicular recording, which is far more stable than previous methods because there is no bit shift--the ends of the magnetic metal crystals reinforce their polarity for smaller, more stable flux prints. All other problems with hard drives, however, remain: bearings, motors, surface contamination, and so forth.

[nestbox]

Thank you to all those that responded, it somewhat clarifies the issue. Regs. M