Back when I used to record on to tapes, I would try to get CR02 or Metal because they provide better sound quality. I know that they have higher bias which allows for better sounds, but I’m curious, what happens when you put the player int Cr02 or Metal setting? I don’t know that much about bias and am pretty much a layman about this, so if someone could try to explain in simple terms, I’d appreciate it. The one thing that is noticeable to me is that the treble seems to be reduced. this gives me a small idea, but I’m still a little lost.
It’s not the higher bias that improves the quality, you just need a higher bias to magnetise the (better quality) chrome/metal tapes.
The wiki article does a good job at explaining what biasing is for but I’ll try a simplification. If the tape was perfect the amount of magnetism applied to the tape would accurately follow the audio signal. Real magnetic materials don’t do that, for one thing you need a certain amount magnetic oomph to get any signal recorded at all. One thing the bias does is to push the signal over the ‘dead spot’ just above and below recording silence.
The loss of treble in the chrome/metal setting is just because those tapes have a different EQ setting from ferric tapes. Essentially they can cope with louder high frequencies, so these are boosted more when recording and filtered out more on playback.
Any better?
Yeah, that helped. Thank you.
Hopefully you answer one more question for me. When the tape selection on the player is set to Chrome or Metal, what does the player do differently?
When playing it just uses a different EQ curve for different types of tape.
When recording it uses a heftier bias (and signal) for chrome than ferric, and even more for metal. That’s why some decks can’t record (properly) on metal tape, the head can’t generate enough magnetism to drive the tape.
Anyone care to explain Dolby?
Dolby is noise reduction by companding - COmpression and exPANDING. On recording, the treble is boosted. On playback, the treble is cut (which reduces the mostly high-frequency tape hiss). Note that this was the simplest form of Dolby, and that many more sophisticated noise reduction systems (including the far superior DBX) followed.
My understanding of Dolby is this: Hiss at a certain (high) frequency is the nature of the beast with cassette tapes. If you just filter out the hiss, you lose some of the music in that same frequency range. So what Dolby does is boost the music in that range on recording and then apply filtering on playback. The filtering removes (most of) the hiss and brings that part of the music back down to its normal level.