....terrific comments, I laughed until I fell off my horse.
I nominate the video above for a "BIGGIE" award, it's like those 'Look At Life' films from the 1960s, and it's very well edited. Take a look-see.......
Yep I know that ”toneburst” sound too – but I think that was more of an internal tonal quality check to see if the sound reproduction was up to standard while manufacturing the XDR's.
I gotta say the XDR's in their transparent shells were a godsend compared to the dross that came before – the late 70s/early 80s EMI white shell/blue ink tapes are just plain sh*te that haven't stood the test of time - then or now. The Dolby B NR sounded like you were listening to it with yer head up a camel's arse. Might've been alright for James Herriott but not I! And the thumping dropouts...
Really a bad quality product for the fans... But it's not true that technology was limited back then - I bought a couple of EMI tapes (here and here) from Greece from the same period and they were amazing quality (many of them have also been uploaded by Dr. Zoze on Tape Media here) – they still play like a dream today and were built like a brick... erm... tape reproduction factory. I swear you can bang nails in with 'em all day and they'll still play-up lovely... And the tracks were in the Proper Order... :-z
I know that cat farting sound. I never paid any attention to it - just thought it was the noise of the tape join going over the play head. You live and learn!
Remember those XDR cassettes from the 1980s? They had a "tone burst" at the start and end, for some reason. (Probably the same reason blank tapes had graphs printed on them - to convince us this was real high-tech stuff!)
I love those screwed shells – if the tape plagged up, you could take them apart and fix it – I've saved many a blank and some pre-recorded tapes that way ;-) But the heat-fixed or snap fix shells... fk*n"&%!grr*cn*t*arse#!
Interesting dialogue guys – I saw something on You Tube that may provide an answer about how tapes were manufactured whilst having little or no room for Ultrasonic Welding (sounds like a mid-80s metal band from Birmingham...). – whilst the tape was wound fully in the shell.
In these clips, the tape shells have been pre-assembled with only a length of leader tape between the spools - thus solving the tape-damage problem whilst heat-fixing takes place – there's no “sound” tape in the shell at all - it's wound on later, as mentioned by TopPopper, giving plenty of room inside the cassette for all manner of clever engineering fabrication shenanegans ;-).
The leader tape is extracted out of the cassette mechanically, and whilst one end of the leader is held, the other end is cut, and gets some “sound” tape is spliced into it. The “sound” tape is then wound back onto the spool inside the cassette, and to finish off, the end of the “sound” tape is spliced back onto the “held” end of the other spools' leader tape. So no fannying about with heat-fixing component parts whilst fragile magnetic tape is 1/1000th of a inch away.
How does the machine know when to stop winding? Well, there's some sonic blips that trigger the stop mechanism – you can sometimes hear them at the start and end of sides on old EMI tapes – they sound like a cat farting (brpbrbrbprbpbbprr).
Thanks for the info, now I am sure I've come across cassettes that's easy to prise apart, and click them back together again, handy for fixing tape breaks etc. Better than gleuing, welding or screwing (Pardon the entendre!). I've occcasion to replace the casing with the c30,60 or 90 cases, which do come in handy, but dead fiddly to get the tape around the spools and the slots, before closing the cases together! I've a few other Canadian tapes by Def Leppard, 1 by Tom Petty that are screwed, you can look them up.
The idea of ultrasonically welding the cassette shell, within millimeters of the tape spool, gives me the heebie jeebies. It must be a very precise process. Is it possible they wound the tape into the casing after the welding was done? Maybe not - but the whole thing sounds improbable to me. It's quite amazing technology in its own way.
Of course, my "lots of ladies in white lab coats on a production line, with tiny screwdrivers " description was pure tongue in cheek, and of course "a five headed monster with magnetic screw heads" was much more likely - wonder if that multi-headed screwing machine was made by Hydra Corporation?
Sonic welding sounds like the answer, but have you noticed how close the two tape transport wheels are to the two lower welding lug points, which must have had the leader tape already installed on the hubs, prior to sonic welding, and close to the point of the weld.
Viewed through a transparent cassette moulding, it looks like 2mm distance, whilst the top two welding lugs are over 10mm from a full spooled hub, and even further from an empty spooled hub. The fifth welded lug, situated behind the pressure pad presents no problems, either.
WIKI: "Ultrasonic welding is an industrial technique whereby high-frequency ultrasonic acoustic vibrations are locally applied to workpieces being held together under pressure to create a solid-state weld. It is commonly used for plastics, and especially for joining dissimilar materials. In ultrasonic welding, there are no connective bolts, nails, soldering materials, or adhesives necessary to bind the materials together... The ultrasonic energy melts the point contact between the parts, creating a joint. This process is a good automated alternative to glue, screws or snap-fit designs."
Interesting. My hunch is that the "glued" tapes aren't glued - they are somehow welded by the use of heat. As you say, prising them open is difficult and it tends to split the plastic rather than the two halves coming neatly apart along the seams.
As for why, I suspect that applying heat for a few moments is cheaper than purchasing five scews, hence it's cheaper to manufacture welded tapes. By the way, I doubt the screws were manually applied - I'll bet there was a five headed monster with magnetic screw heads, which could do it in a trice. Still more costly though.
This tape media site gets more interesting day by day......
Take a look at the cassette shell above, it has the five machine screws to hold the two parts of the cassette shell in place, not permanently glued together as on the majority of mass duplicated cassette tapes produced for retail sale.
The custom black polystyrene shell also has "Made In Canada" embossed into the moulding, so I wonder why a 1986 cassette tape has the screws present, when in UK from at least 1972, most duplicated tapes were glued together, at point of production, never to be taken apart.
I have used cassettes since 1968 or so, and have repaired plenty that had snapped tape and other ailments. Just try to get apart a cassette shell that has been glued together without totally destroying the shell.....it's not easy.
I have well over a thousand blank cassettes, as well as plenty of retail pre-recorded cassettes, and the majority of the Sony, TDK, Hitachi, Maxell, Philips, BASF etc. shells can be disassembled for repairs, if necessary.
I have a few cheap crap blank tapes that I bought used, and they seem to be of the glued variety, so it makes you wonder why the tape duplicating plants used glued together cassette shells, instead of that shown above.
It must have been a time constraint, because having staff screw thousands of cassettes together would not earn any more dollars, so glueing was cheaper and quicker.
( just hold that thought, lots of ladies in white lab coats on a production line, with tiny screwdrivers assembling the two cassette shells and all the gubbings that go inside them, then screwing the shells together with five chrome plated tiny screws......I'd have gone nuts after one hour... )
How come blank cassettes are screwed together then, they must have been assembled on an automated production line, and they didn't charge £6.99 a pop for the resultant product, ( I know you'll bang on about the artists royalties.....they got about 10p per tape, the rest went to the record company, VAT and the retailer....)
...rant over, I'll go and lie down quietly now......