Experimenting with overbias: Observations on SM911 for 8 track
- Thread starter shedshrine
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A Reel Person
It's Too Funky in Here!!!
Interesting.
The last cal I did, Tascam 34, the manual said 3-4 overbias for 456 @ 250nWb/m, so I did 4db overbias on each channel. It just seemed easier and more accurate to shoot for 4 rather than 3.5. That's IIRC. I figured if the manual said 3-4db, anything in that range would be acceptable.
The last cal I did, Tascam 34, the manual said 3-4 overbias for 456 @ 250nWb/m, so I did 4db overbias on each channel. It just seemed easier and more accurate to shoot for 4 rather than 3.5. That's IIRC. I figured if the manual said 3-4db, anything in that range would be acceptable.
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Beck
Guest
And every type (Brand/model of machine) is different. Bias settings for a given tape depend on head gap and tape speed. Normally if you have a machine correctly setup using 456 then SM911, SM468, Scotch 986, etc, will sound "Right." But anyway, there is a window for bias setting. It is not necessarily a precise number, but more of a set to taste situation.
WarmJetGuitar
New member
Does this mean that 456 is close enough to SM468 so that you won't have to recalibrate between these tapes? If yes thats great news to me.
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Beck
Guest
AGFA/BASF/EMTEC SM468 was one of the tapes traditionally used on machines setup for 456. I set my machines for 456 and leave it there. I use Everything from Scotch 206 and Quantegy 406, to SM911 and SM468 without making any changes. Back in the day I also used Scotch 226, but that stuff has all gone sticky and I wouldn't touch it these days.
Some people, like Frank Zappa, even spliced 456 and 468 in together on the same reel. Gives you an idea how close they are in practice.
468 is not technically bias compatible, but in practice it works for most people except those who are really picky and will even rebias with each reel of tape, even the same brand and model tape.
The only truly bias compatible tape still being made is SM911. Back in the day we also had AGFA 469 and Scotch 226 that were made to be drop-in compatible with 456, but both of those are the worst for sticky shed now. SM468 or PEM 468 (original AGFA model number) are all good.
WarmJetGuitar
New member
Pwew, then after all I didn't making that much of a mistake when I left some 468 with the second G16 that has arrived to our small studio. It was the only blank tape we had left that I knew wasn't sticky, I had noticed that we'd bought all the empty non-sticky tape he had and the guy assumed that we wanted it calibrated 468. I felt so stupid for not mentioning we meant to use SM911/456 most of the time but after all it wasn't so bad. But it sounded slightly off when I tested the machine with a psychefolk recording we've done using some +3 Maxell tape on our uncalibrated G16. It was recorded with pretty hot levels while on the newly calibrated G16 it looked as fairly conservative levels dancing around 0. Weird. I don't mean to be threadjacking, but how come?
Better just stick with the uncalibrated G16 for the rest of this album and it calibrated for 468 later I guess. I know it's stupid starting a long project with an uncalibrated machine but it sounds fine and we're on a tight budget and MRLs are expensive.
I'm rambling, perhaps I should get some sleep.
miroslav
Cosmic Cowboy
I have both my Fostex G16 and my Otari 5050 BIII calibrated for 456/911...but I'll use 468 without even blinking.
I would complete the song(s) you've started with the deck uncalibrated....mix them down or transfer them to a DAW or whatever your plan is.....then calibrate the deck for 456/911 and continue recording with a fresh reel. If you have 468, you can use that also, like Beck said. You don't need to sweat the differences between 456/911 and 468.
Better to wirj with a calibrated deck than not....even if you think it "sounds" fine.
I've recalibrated my G16, and then pulled out some older recorded tapes, and you can easily hear/see the differences...mostly in the levels.
I would call the 468 just a "cleaner" version of the 456/911....IOW, it doesn't as as much color as the 456/911.
IMO...I don't think 456 and 911 are the same either. I mean, they are electronically compatible/interchangeable...but I would call the 456 the most "colorful" when hit right, then the 911, then the 468.
Beck can chime in...I'm sure he has a more detailed perspective on the subtle sonic differences between 456, 911 and 468.
I would complete the song(s) you've started with the deck uncalibrated....mix them down or transfer them to a DAW or whatever your plan is.....then calibrate the deck for 456/911 and continue recording with a fresh reel. If you have 468, you can use that also, like Beck said. You don't need to sweat the differences between 456/911 and 468.
Better to wirj with a calibrated deck than not....even if you think it "sounds" fine.
I've recalibrated my G16, and then pulled out some older recorded tapes, and you can easily hear/see the differences...mostly in the levels.
I would call the 468 just a "cleaner" version of the 456/911....IOW, it doesn't as as much color as the 456/911.
IMO...I don't think 456 and 911 are the same either. I mean, they are electronically compatible/interchangeable...but I would call the 456 the most "colorful" when hit right, then the 911, then the 468.
Beck can chime in...I'm sure he has a more detailed perspective on the subtle sonic differences between 456, 911 and 468.