Hi guys/gals,

I'm about to embark on a project to salvage my parents' collection of audio tapes. They are quite ancient, some almost as old as I am. Since I can only see threads regarding to salvaging LPs, I want to ask some questions:

1. What precaution(s) must I take beforehand?
2. How do I connect the tape player with my PC? I plan on connecting the earphone out of the tape player with the line-in of the soundcard. Will that do?
3. Would you recommend keeping the audio file as a big file with .cue's or split them into individual songs?

Thanks in advance. Any tip helps.

You did not say if they were reel-to-reel or casette. I have read that casette tapes "dry out" or lose their lubricant over time. A cure is to open the casette, spray it liightly with WD-40, lets it soak in overnight and then play it. OK, I have never done this so if I were you I would test it on the least valuable tape first.

Restoring audio tapes is basically the same as restoring vinyl, whether it be cassette-tapes or reel-tapes. Most important thing for the restoration is the quality and the condition of the tapeplayer that you are goin to use.
Try to get a good one and make sure that the heads and the rollers that touch the tape are perfectly clean. You can clean heads and rollers with alcohol.

There's not much you can do about the condition of the tapes. If they have suffered over the years and lost some of its audio signal (= magnetism) then you will get no better than that. I would be very careful in applying WD40 to the cassette. It may be good for lubrication of the mechanical parts but I don't know whether it will affect the tape itself. If the tape will run I would leave it to that.

You can connect the tapeplayer to the line-in of your PC and record the audio with any decent wave-editor. If you want to use the earphone-out on your tapeplayer you should check if the signal level is enough for the line-in. The latter generally requires a higher level than the earphone-out will produce. If possible I would try to find a player with line-out. That would match anyway.

Good luck !

@boojum: They're cassette tapes. I don't think they stick or something, but I heard you have to throw away this thin sheet of plasticky thing inside the tape, and check the cassette's rollers, perhaps replace the foam pressing the tape against the reading head.

@arpeggio: Thanks. I guess I'll have to borrow a line-out-equipped player then. You're right, testing the current tapeplayer with a new cassette doesn't produce enough power, even with volume cranked up to the max.

FYI I use Adobe Audition 1.5, which I think should be enough.

Oh, another question:

4. What volume should I set on the tapeplayer? I guess I must not set it to the max, am I right?

If you mean the level for the earphone-out, you're right. I would definitely not set it to the max. Because this is analogue equipment you will get a higher amount of distorsion in the signal. I would set it around 70%.
When recording you can adjust the level of the signal with the input level of the wave editor.

If you use a tapeplayer with line-out then it should have a fixed signal level. Mostly around 500 mV.

Ah, okay. Thanks for the pointer.

Well, now to prepare for days and days of recording...

Any suggestions in terms of wave-editor software? Thanks.

I use WaveLab and pepoluan has Adobe Audition (used to be Cool Edit Pro). Both are nice wave editors, but not for free.

A good wave editor for free is Audacity.
But there are a lot more.

Thanks argpeggio. One more thing. Once the tracks are encoded to wave, is there a way to edit the files, say, to remove unwanted "noise" such as tape hiss?

You may want to try to hunt down a component system cassette deck, i.e., one that hooks directly to a stereo receiver/amplifier at line level via red/white RCA connectors. No gain/level/volume adjustments on the tape player to worry about. You could then run it to your computer via a RCA-to-stereo-minijack adapter - these are fairly easy to find here in the U.S. at a radio shack or similar type electronics equipment store.

Also, just out of curiosity, I'd be interested in knowing what people do (if anything) to correct for "tape hiss." For example would it be better to record from a tape player having Dolby B or C noise reduction enabled, or to instead apply some sort of DSP/filter to the recorded WAV? EDIT: hiwaycallin beat me to this question by a matter of minutes.

Slightly OT but my first portable music device was a pre-"walkman" cassette player circa 1983 having only 3 buttons: play, fast forward, and stop.

Ah yes I saw such deck at my church. Kenwood, IIRC. Good enough?


Well, you really should turn on Dolby NR only if the tape is mastered with Dolby NR. IMO, whatever helps reducing noise, must be used. So I think I'll turn on Dolby NR if the tape is mastered using Dolby NR.

Also IIRC Audition has the capability of doing/compensating Dolby NR... I think I read about it in the help... will check it out.

From my old days of "hi-fi", Kenwood had (and perhaps still has?) a reputation for producing good audio equipment. Nice find.


Ah, I forgot that the tape itself needed to be mastered w/ Dolby NR! Shows how long I've been away from cassettes!

I have used an application called Algorithmix Sound Laundry. It would work okay but to find the right settings was a matter of trial and error. It has been some time now since I used it so I don't know if this app is still available.
Cool Edit used to have an option for Noise Reduction and of course Adobe Audition has it too.
Any application for pro sound engineering have plug-ins for noise reduction but unfortunately I don't know of any plug-in for free.

As to Dolby NR I confirm what pepoluan stated. If the tape is mastered with Dolby then you should play back the tape with Dolby on. If not, then you should leave Dolby out, otherwise you will get a completely wrong frequency response in the play back signal.

edit: Remedial Sound just came up with the same warning

If you don't have a Dolby NR-capable tape deck, you have to suppress the treble part of the signal, i.e. slide the treble slider to its lowest setting. IIRC if you have a graphic equalizer, bottom out all sliders from 14kHz upwards. Or was it 11kHz?

Argh, I forgot... Now I have to hunt the info through Google

.... ahh Dolby, that was in the 70's and the 80's ...

For people who really want to dig into this subject, here's an interesting thread in HA Forums 2003:

How to Clean up Cassette to Digital

Have fun !

Ah, never thought it would be that complex before, esp. the azimuth correction.

Hm... I think I'll take my chances due to 1) The huge amount of cassette tapes my parents have and 2) I think I'll use the church's Kenwood tape deck, and if I tinker with it and it sounds muffled during the next use in church...

I'd rather trying to fix everything up with Audition. Been getting great results post-processing some local artists' album recordings nowadays

Adobe Audition 1.5 (and above) has a REALLY useful feature - spectral waveform editing. I've been using it to remove unwanted motor and AC hum from my vinyl recordings - I record a waveform of the track, warts and all, then view the waveform in the spectral view. Using that feature, I can select a band of frequencies to process, so I select 0Hz - 4KHz of silence (basically groove noise before the record begins, just to get a representative sample of the AC hum and stuff), capture that as a noise profile using Audition's Noise Reduction feature, then apply the Noise Reduction process to the entire waveform - I find it works incredibly well when you apply it to a band of frequencies.

It's not the be all and end all, but provided you tweak the Noise Removal settings just right, I'm fairly sure you could achieve some excellent results in attenuation of excessive tape hiss, before you do your EQing (because you'll need to do some subtle EQing) whilst still keeping the original sound pretty much intact.

Happy experimenting...

*gasp* Christopher, you're leaking our secret away!

There is this one : http://www.hydrogenaudio.org/forums/index....t=ST&f=1&t=8990
My father advises to rewind the whole tape before playback if it has not been played for a long time, however I don't know if this is just a snake oil remedy or something useful. I know that old tape tends to stick to itself, and that the rewinding is aimed at unsticking it.

I've got a dead cassette. The tape had become completely slippy. The right side reel would pull the tape at high speed through the playback mechanism. The pressing rubber was not capable of holding it at the right speed, it was slipping through ! The cassette reel could also be turned by hand like a roll of paper that you strengthen. Instead of stopping at the end of the tape, it would go on turning over itself, making hissy noises.

I've read an interview of someone of the Star Wars crew. He was saying that in order to remaster the old movies, they had to use tapes 20 years old, and that some of them had become unuseable. Their trick was to heat them for a short time in an oven. But this is a tricky process. They melt some of them by mistake

I was messing around with tape restoration some years ago, but my results were very unsatisfying. After 20 min of playback there was a thick brown film on the head (i'm talking about 30 year old tapes), that was hard to remove and eventually i never used that casette deck since then.
I've found it much easier to download the songs from p2p instead, with better quality and much less work.

Another reason for doing this I've heard is that when you've been playing parts of the tape, rewinding, fast-forwarding, playing again, etc, the tightness of winding will differ between the parts that were wound at different speeds or in different directions (makes sense especially for single-motor decks). Upon playback this could cause some change in pitch every now and then.

pepoluan, this is a little guide I wrote about how I digitise cassette tapes: linky

As I say at the end of the guide, this might not be the perfect way to do it, BUT this is how I do it and have achieved some great results.

I actually use my Rockboxed H120 instead of my PC now (using the Recording Enhancement Pack at the mo too, which is just great).

Certain tape formulations, used in a certain former time period, possibly from a single major manufacturer (Ampex?) are very subject to "shedding" after enough time has passed. This is due to moisture absorption. Baking the tapes restores them. This is a very widely practiced and safe practice but can only be successful under careful temperature control. A fairly in-expensive home method uses an incandescent lightbulb with a brightness control,, mounted in a cardboard oven -- with a good quality thermometer. After adequate calibration, the oven will hold the set temperature pretty well under normal in-the-home conditions.

Tips from when I used to use cassettes a lot:

Cleaning

You really should clean the deck before running cassettes through it, it'll greatly reduce the chance of tape disasters. If you can't find one of those cleaning cassettes with cogs and (clean) reciprocating pads in (which you soak with isopropyl alcohol / IPA - cheap from a chemist / pharmacy) then you'll have to do it by hand, which can be fiddley. Don't use one of those "Head Cleaning Cassettes" consisting of a short run of white tape - they make negligible difference to the bits that matter.

To clean the tape deck by hand I used cotton buds and IPA. There used to be chamois head cleaners available, like the tools a dentist uses, only with a little square of chammy leather on the end. This was to avoid getting bits of cotton bud everywhere, but you can always see when you've done that and get them out in the end.

Use a bright light to see what you are doing.

Give the heads a quick wipe with a cotton bud dipped in IPA - they're rarely very dirty.

The bits that really need cleaning are the pinch roller (rubber roller) and spinning metal post it traps the tape against. There will be two sets of these if it's a dual direction deck.

Set the deck playing with the door open. Sometimes you'll have to defeat a micro-switch that confirms a cassette is present. It'll be alongside the switches that detect if a cassette has had its record protection tab broken out. Other times you'll have to spin the take-up capstan with a spare finger to prevent the auto stop activating - that can be a pain.

Hold a cotton bud dipped in IPA [edit: I have since found out this can dry the roller and cause cracking, although I always got away with it. Rubber cleaner should be used] and against the now spinning roller, turning it as it gets dirty. If the deck hasn't been cleaned for a long time you could go through both ends of half a dozen cotton buds before they come away clean.

Give the spinning metal post a clean too - pausing the deck can help here, but if that doesn't work then the cotton bud will get trapped a few times, but it's easy enough to unravel it all and get the cotton bits out.

Re-tensioning

Tape, especially if it has been played in a car or walkman, can get unevenly wound so the sides of the spools aren't flat. This can drag against the slip-plates inside the cassette excessively, causing pitch shift, or even jams.

On any cassette deck - I always used an old portable with the door taken off - rewind the tape from one end to the other whilst applying gentle pressure, with your finger, to the capstan the tape is coming from. With really unevenly wound tape it could take a couple or so of runs through, applying a little more pressure the second time, but not enough to cause the motor noise to change.

C120 cassettes

These were made of extra thin tape and can be troublesome. They jam more, wrapping round the pinch roller all too easily, can stretch and even break, and they suffer more readily from shedding of the magnetised coating, causing drop-out in the audio. Fortunately they weren't often used for music, only voice, and you're not likely to come across commercial recordings on them.

Find someone that has one with at least Dolby B NR, and HX PRO - these logos will be labeled on the unit itself. If you find someone that will lend one to you for the length of time it will take you to complete your project you won't regret it. I personally think it's better than using some noise removing filter in commercial end-user software (not professional studio remastering technics) that could very easily have unappealing results such as mildly to drastically changing how songs sound quality-wise. I tried some noise reduction within Cool Edit 2000 back when I was converting my cassettes and I quickly abandoned it because the results weren't that great.

To reiterate southisup's comments; it wouldn't hurt buying one of those tape path cleaning cassettes to keep the tape path, rollers, heads, etc., as clean as possible from the old cassettes since they'll be shedding oxides - most drug stores should sell them dirt cheap.

Also inspect the cassettes to see if they are in need of being transplanted into a new cassette casing, or if they need a new foam cushion.

That's what I did before I began my tape->digital conversion project back in December 2003. I however didn't do it in the mindset of unsticking tapes. I merely wanted them wound tightly so that they wouldn't get jammed in the tape deck. Doing that also helped me found a few defective tapes that would have probably been eaten by the tape deck.

One additional question:

My church's sound engineer told me to play this "Tape Demagnetizer" casette every 5-6 casettes that I played, with the deck unconnected to anything (except power).

That casette is not a normal casette, it has its own battery and what looks like an electromagnet on a cam, moving it up and down to & from the reading head. No magnetic tape at all.

What is this thing? And what effect does it make on the deck?

It's allot safer than waving around a large VHS type tape demagnitizer which could easily damage nearby T.V.'s and other devices.

It's one of these and looks like this (although I can't say it works or doesn't work):

Magnetic tapes work by storing the signal as a magnetic pattern. The magnetic field in the tape tends to induce a magnetic field into any metal parts of the tape deck that contain iron. These induced field then adversely effect other tapes that are played or recorded, the general vicious circle. Demagnetizing clears the induced magnetic field from parts in the tape path.

I don't know how well such a device as you describe works, relative to more traditional demagnetizes, but the recommended schedule seem excessively frequent.

@Andavari: Um, I think that looks like it somehow... the one handed to me was made by Philips and all moving parts are orange-colored.

@AndyH-ha: Ah. Based on your explanation, I think my friend's advice is not too excessively frequent as the tapes I'm about to play are old tapes, thus the ferrous particle may affect the head more adversely.

And remember that this is a *vital* tape deck that I borrowed

Then, ask the owner his/her opinion.

-brendan

The one responsible for the deck did provide me his unsolicited opinion, as I posted previously, of demagnetizing every 5-6 casettes.

Ah, my bad, should have read back to the beginning.

If he also gave you the demagnetizer use that. Otherwise, the faux-cassette based ones are probably safest compared to wands. However, examine it closely and test it out on a cheaper deck first. The ones I remember from back in the day typically had a low-friction coating on the demag head to prevent damage to the deck head, and the coating should be clean and intact.

-brendan

The age of the cassettes, or the stability of the ferrous coating, is irrelevant. This is not about cleaning debris from the tape path, it is only about magnetic fields. Older tapes that are losing their coating only have the potential of creating less magnetic contamination, never more.

There is a problem of sorts with these mechanisms, depending upon the tape deck. Most better quality decks will only move the tape heads into playing position when turned on. Most demagnetizers of this sort have their on switch activated by pressure against the tape heads. This means the tape deck must be powered on to use the device.

The circuitry in the demagnetizer, or at least in most of them, puts out a very strong signal that will overload the associated tape deck electronics. You most certainly don't want to have any speakers or headphones able to receive a signal while doing the task. I guess you cross your fingers and hope nothing inside the tape deck becomes too unhappy.

I don't recall ever seeing anything to suggest that the magnetization of the tape deck parts is in any way damaging to the deck itself. The magnetic field only adversely effects tapes being played or recorded in the deck. When the deck is demagnitized, the end result is the same to the deck whether the field build-up resulted from 5 cassettes or 500 cassettes.

Hm, this demagnetizer has its own power switch. The cam action actually oscillates the demagnetizing head up and down a track inside the cassette, but the demagnetizing head never touches the reading head.

Well, my friend did warn me to make sure the deck is not connected to anything except the power lines. Since he's been using the demagnetizer for quite some time, I guess the deck is just compatible with the demagnetizer.

Okay *crosses fingers* here I go...

Oh and keep those inputs coming in... anything to prevent me re-doing this 200+ tape salvage project is surely welcome

If you're going to clean the heads after each tape (which you probably should with old tapes) then use a very soft cleaning device. Some of the "head cleaning tapes" were very rough, and will wear out the tape deck heads very quickly - certainly before you get to the end of your 200 tape project!

Demagnetising after every 5 tapes is just stupid. Are you sure it is a demagnetiser? (Or if it is, is it a good one?). The ones I've used don't have moving parts - they don't need it - there's a fixed head which outputs an AC magnetic field to demagnetise the head in the deck. Job done.

Just play the tapes. Don’t bake them or oil them! Buy a few new blank cassettes, of reasonable quality with screwed together (not glued) cases, so you can easily take them apart. Then, if you find a tape that won’t play properly (and that includes making a “squeaking” or “squealing” noise while otherwise playing “properly”), open up that cassette (small screw driver if it has screws, carefully prise it open if it doesn’t) and put the magnetic tape itself into the case of the new tape. That way, only the tape is old – all the rollers, pads etc are new. It might help.

If you're not going to set the azimuth correctly (and note that many decks don't let you set it) then you might as well not bother doing the job at all. If you trash the high frequencies by using a different azimuth to play the tape from the one used to record it, then no amount of post-processing is going to recover them properly (though CEDAR claim to make a $5000 box which can try).

Finally, if you're going to perform noise reduction in software, do it carefully. Most people try to remove all the noise and end up trashing the sound in the process. Better to leave all (or some) noise than remove some of the content or introduce processing artefacts.

Cheers,
David.

P.S. If these are home recordings of important events, they’re probably worth saving. If they’re commercial music cassettes, you’re wasting your time if the music is available on CD. Even if you can’t now (I don’t know if you’re a school kid or an adult!) one day I’m sure you’ll be able to work for the time it takes to transfer and restore the tape to earn more than enough money to buy the CD! So don’t waste your time.

@2BDecided:

I have a Philips-brand cleaning casette that does not use an abrasive tape, instead it uses this crazy looking mechanism with a foam(?) that gets wiped back-and-forth over the reading head. It also has the same material that is pressed against the capstan & rollers. All the foam materials are replaceable, and the kit includes 3 replacements for each.

I tried measuring the magnetic field, and yes I think the demagnetizer is a demagnetizer. It's a bit difficult measuring how powerful the field is as the demagnetizer keeps moving. I don't know why it must move up and down, but my friend swears by it.

As for azimuth correction, I decided that I don't dare to do it. Some of the sorriest looking tapes seem to still be bright enough, and all artifacts caused by crinkling of the tape.

And don't worry, I'm quite experienced enough in processing audio (did some mastering for some local bands, actually), so I know how much I should manipulate my audio. One rule: Always work on a copy of the original

And finally, no they're not home recordings, but most of them are not (and most likely, will not) be available on CDs due to... a lot of reasons. These 200 tapes are the irreplaceable ones. The other 300 or so has been replaced with CD's or MP3s downloaded from the Internet.