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Bulk Digitizing Old Cassettes

All about the tools and techniques involved in capturing sound, in the studio or on location.

Re: Bulk Digitizing Old Cassettes

Postby ken long » Thu Dec 06, 2018 5:18 pm

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Re: Bulk Digitizing Old Cassettes

Postby Mobileman » Thu Dec 06, 2018 8:37 pm

All of you are awesome, I feel like I just earned my doctorate in "Advanced Cassette Digitization." Seriously, there is a wealth of solid, workable knowledge. Two very good suggestions are leaving them unprocessed, just transferred since the material will be preserved, as it is, and nothing more. This is difficult as I am not an audiophile by any means but it seems almost disrespectful to record a musical performance with more noise than music.
The low -pass filter should provide a great deal of relief for the listener, even if it does nothing to enhance the musical details. I'm not sure how to apply this at the input, but even without much experience a trial version of Ableton Live has in?out channel routing (or looping if that'a the the correct term). Though you can't save files with the trial version, I don't think it would be against the law to capture the playback and save it with another DAW.
Lastly, mentioning Izotope RX suggests a real easy solution. The newest version offers a features that listens to a sample, suggests presets to improve and then applies them automatically to the files.
All of this suggests that even though we have long thought of mixed music as impervious to "un"mixing, the future holds all sorts of possibilities.
Again, thank you all for your very kind concern and assistance. I'll try to let you know what transpires. Happy Holidays.
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Re: Bulk Digitizing Old Cassettes

Postby Tim Gillett » Fri Dec 07, 2018 12:43 am

Hi again Mobileman,

You seem to assume that the very muffled, noisy sound you report hearing is the best that can extracted from the cassette tapes. James, myself and Ken, all of whom have done this as paid work for many years have been trying to suggest the tapes may actually contain significantly better sound quality than you have been hearing.

None of us here knows what sort of playback machine you have been auditioning the tapes with, or its condition. Could you describe it?

As Ken wrote: "Yes there are tools for post processing but they won't restore that which was never captured."
For starters, before playing a cassette, have you tried James suggestion to carefully and thoroughly clean the tape path in your machine ?
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Re: Bulk Digitizing Old Cassettes

Postby MOF » Fri Dec 07, 2018 2:47 am

Don’t have the Dolby button engaged when you transfer the tape. Misalignment between the record and playback machines can cause a muffled sound. Better to have a slightly brighter but hissier sound in your case I would have thought. If there is a tape type selector then match that to your cassette.
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Re: Bulk Digitizing Old Cassettes

Postby Tim Gillett » Fri Dec 07, 2018 5:46 am

MOF wrote:Don’t have the Dolby button engaged when you transfer the tape.

Misalignment between the record and playback machines can cause a muffled sound.

Better to have a slightly brighter but hissier sound in your case I would have thought.

If there is a tape type selector then match that to your cassette.

Yes all good points.

Keeping Dolby or other NR off is important. It's difficult to undo Dolby decoding after the fact.

With slow speed cassettes, read head azimuth misalignment is very common but even more fussy if replayed on a mono machine, or stereo summed to mono. James mentioned this early in the thread.

Yes the rule when capturing is to capture everything, including all the tape hiss. Even if it is objectionable to our ears. This also keeps the inevitable tape machine preamp hiss to a relative minimum. Maximise the program signal so that it predominates and so masks the preamp hiss. Unless the playback is maximised off the tape head, the roles can reverse, preamp noise can predominate, and the inexpert person can assume all that noise is unavoidable tape noise.
A good test when replaying a cassette is to listen from the very start of the 5 second plastic leaders at the beginning of a tape side. As soon as the actual magnetic tape hits the head there should be a noticeable increase in clear, steady, sharp hiss. That at least suggests that the tape is in reasonably intimate contact with the read head.

"Tape type" is more easily undo able as it's a predictable, static LPFilter, and at only 4db at 10kHz, is fairly mild in any case. For people with HF hearing loss it may not even be noticed. But yes, better to capture it at "Type I " setting as (in this case at least) it's most likely they were Type I tapes recorded by a machine which assumed Type 1.

Another issue is the cassettes themselves. Especially older cassettes can have a worn, or damaged pressure pad. This can cause partial or complete loss of signal. The pad is also designed to provide a certain braking force on the tape. Without this "back tension" tapes can be chewed up by the pinch roller and capstan.
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Re: Bulk Digitizing Old Cassettes

Postby James Perrett » Fri Dec 07, 2018 12:17 pm

Tim Gillett wrote:Another issue is the cassettes themselves. Especially older cassettes can have a worn, or damaged pressure pad. This can cause partial or complete loss of signal.

That's a good point Tim which I forgot to mention in my previous post. I've had quite a few old cassettes recently where the pressure pad has come unstuck and gone missing. In cases like this I usually transfer the tape to a new housing.
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Re: Bulk Digitizing Old Cassettes

Postby Wonks » Fri Dec 07, 2018 12:20 pm

Unless it's an old blues recording, when it's a how, how, howsing.
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Re: Bulk Digitizing Old Cassettes

Postby Tim Gillett » Sat Dec 08, 2018 1:03 am

James Perrett wrote:
Tim Gillett wrote:Another issue is the cassettes themselves. Especially older cassettes can have a worn, or damaged pressure pad. This can cause partial or complete loss of signal.

That's a good point Tim which I forgot to mention in my previous post. I've had quite a few old cassettes recently where the pressure pad has come unstuck and gone missing. In cases like this I usually transfer the tape to a new housing.

Yes I sometimes reshell the tape or just replace the felt pad and its metal spring with a new one. But I try and avoid using the cassette pressure pad altogether, and generally use Nakamichi dual capstan machines with the pad lifter. Apart from anything else, I find the Nak type pad lifter extends the life of the valuable play head.

All the best,
Tim
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