Steve_Graham@ub.cc.umich.edu (10/09/90)
Many of my reel tapes were recorded on stock made in the 70s, which recently has been found to squeal. Because I had been having problems with tapes squealing I had obtained Last's formulas 9 (tape head treatment) and 10 (tape treatment). Today I tried to play my tape of Shostakovich's 6th symphony. I'd never considered this to be a very good recording; it had quite a lot of upper frequency grit and grain, which I had attributed to the fact that I'd used the very inexpensive dbx NX-40 noise-reduction unit to record it. This device has lots of sonic problems that are corrected in the dbx 224x which I now use when I need noise reduction. The tape started to squeal right away, during the opening bars of the work. So I decided to try the Last treatments. First I applied formula 9 to the heads and tape path, hoping that it would not be necessary to treat the tape itself, a thing about which I have misgivings. After treating the heads I tried the tape again. It soon started to squeal, but before it did I got quite a surprise: about 85% or 90% of the grit and grain had vanished! Could it be that much of the sonic trouble I had attributed to my cheapie dbx were really the result of scrape-flutter? I don't know, but I wonder what this will do for my *other* tapes! Meanwhile I still had the squeal to deal with. I tried applying Last formul 10 to the tape. I had high hopes for this, from reading what others had said, but it didn't seem to change anything. I listened to the tape-deck itself to see if I could find out where the squeal was coming from, and it was strongest at the playback head. So I gave that head an extra dose of head treatment, and also reduced the tension (playing a 10-inch reel on 7-inch tension) and was able to play (and enjoy) the tape successfully. So it is still an open question how effective the Last products are for reducing tape squeal problems. (Certainly the stuff is expensive!). But the tape head treatment does seem to improve the sound, something I had not at all expected. As I learn more I'll try to keep you posted. --Steve (sg2@ub.cc.umich.edu/USERHEFX@UMICHUB.BITNET)
jj@alice.att.com (jj, like it or not) (10/10/90)
In article <6840@uwm.edu> Steve_Graham@ub.cc.umich.edu writes: > > >Many of my reel tapes were recorded on stock made in the 70s, which >recently has been found to squeal. Because I had been having problems with (just leaving in the first line for context) Sounds to me like Steve has demonstrated the definitive version of "scrape-flutter". This is a mechanism where the irregularities in the tape's passage over the head introduce sidebands (well, a blecherous form of FM modulation) into the recorded signal. It's one of the absolutely WORST subtle tape defects (it's on ALL tapes to some extent). Furthermore, some people LIKE it. Oh, sigh. In any case, the reason things may have sounded better while the conditioner was on the head could well be that the scrape flutter was quite lowered, ergo things did sound better. The squeal is indeed an awful form of scrape flutter, that's audible from the periodicity of the change in tape speed due to some dynamic contraint or other. -- Rince *Copyright alice!jj 1990, all rights reserved, except Philib *transmission by USENET and like free facilities granted. 'A *Said permission is granted only for complete copies that Choeil *include this notice. THIS MEANS YOU.
lstowell@pyrnova.pyramid.com (Lon Stowell) (10/15/90)
Considering that this is the high-end board, this may get flamed..... but... I have a friend with a Nakamichi RDAT set-up who just recently began portation of all his priceless reel-reel tapes over onto RDAT. Unfortunately most of the older tapes had lost their lube and squealed like stuck pigs... LAST saved the day... Too bad there is no inexpensive WORM recorder for real archival, but hopefully the RDAT tapes will last long enough till there is... The WORM is the acronym for "Write Once, Read Many" technology. Specifically a CD recorder for the home. We have a Sony WORM here at work, but who wants to buy a Pyramid at $200K just to record and playback audio and/or video? Or would that be ultra high-end audion... WORM would be able to record onto CD's which, rot rumors to the contrary, would likely outlast ANY magnetic tape formulation....