Voice recording issues when the master copy is flawed

I’m sorry to both you all- but I though a form like this might be the best shot I have of getting some advice.
About 15ish years ago (give or take) my grandmother recorded family history on a cassette tape for me. She pas alway not long afterward-. I still have the tape- and friend were kind enough to place it on MP# and CD for me this year. However when at some point near the end, the tape got … grabbbled. It High pitched and squeky the her would indeciferablee (kind of like if you tried to press play and fast-forawd at once I suppose- or were talking with helium balloons) this happen in the original recording- supposedly do to low batters on the cassette recorder. I had hoped to be able to fix the problem with Audacity-I tried fiddling with both speed and tempo and pitch. So far nothings worked- I still hope i can be done- but i not a music person or a PC person- and I have no idea what function I need- or what the meesuremnts given on each mean.
If anyone can give me advice I’d be forever greatfull. This recording was made very shortly before she died, theres no way to ask her what she said. I hope to give copys of this recording to my family- especially my Dad since she was his mother.
Doe anyone have any advice at all?
Thank you in advance

take the original tape
slowly play it through a couple of times both directions
do NOT FF or rewind !

first though see if there is any sticky goo on the sides
if so you need to bake it
[google for proper way to bake a tape]

then play the tape again through any working cassette player
and make another copy

if you have a real sound card in the pc
with rca jacks
that would be good enough
if not buy the audio interface recommended on many other messages

do NOT use the little connector that the mike goes into

your existing cd and mp3 cannot be fixed at any cost you could afford – if at all

In Audacity 1.3.12 you have the Change Speed effect, which you can use to slow down any portion of the recording that is at a constant speed and too fast. If the sound is getting faster and faster, there is the Sliding Time Scale/Pitch Shift effect which can be used to incrementally slow down the recording. Finally, you can put a Time Track in your project and use it to control the speed of playback.

Change Speed: http://manual.audacityteam.org/index.php?title=Change_Speed

Sliding Time Scale/Pitch Shift: http://manual.audacityteam.org/index.php?title=Effect_Menu#slide

Time Tracks: http://manual.audacityteam.org/index.php?title=Time_Tracks

If the speed up on playback (slow down on recording) is severe, you may need to apply the effects multiple times. As I understand your post, you are mainly interested in transcribing what was said. These effects may be able to do the job. Don’t give up. It will certainly take much time and experimentation.

– Bill

The mains hum signal on the recording, (50Hz Europe, 60Hz USA), could be used as reference when correcting the speed.
Use Audacity’s “Analyse”, “plot spectrum” to see where the mains hum fundamental frequency has been shifted to by the tape speed change.

[This sounds like a job for an autotune-type effect but with real-time adjustment of tempo, rather than pitch, to correct for the variations in tape speed].

If this problem is on both your MP3 version and on the original tape, then I would recommend not messing with the tape just yet, (until we have exhausted all other options) as the recording is clearly very valuable to you.

It would be very helpful if you could give us some idea of how bad the damage is.
Are you able to edit the mp3 to make a short track with a couple of seconds of the “good” part and a couple of seconds of the “bad” part. Then Export the edited track in WAV or Flac format and upload it to the forum.

Thankyou all for the advice. I will see what I can do about uploading the file soon - Your quite right I’m a more then a little scared to risk the master cassette at the moment (though I appreciat the suggestion from who’s ever idea it was to use it.) I will try other the methods mentioned as well. Thank You all once again.

we need a better description of the real problem
posting a clip may let the golden ears here figure it out

sounds like you got a sticktion like effect at the end of the reel
with insufficient take up torque andor
too much static electricity or leaky goop holding the tape back –
especially if it were rewound of FFd before storage
with possibly some slipping on the capstan roller if it is too old and hard and slick

exercising the tape at normal speeds should not hurt it
(may hurt the player if there is sticky goop – so you will need to bake it first) [hold off on baking until you try the other methods]
you can move it slowly and safely by hand with a bic pen stuck in the reel. if no goop, all it needs is to be exercised at low tension to free it up. then play it on a good player with adequate torque.

There’s little you can do with the master cassette, so keep it safe as a last resort. “Stiction” and “gooey tape”, with the remedy of baking the tape, applied only to specific brands of reel-to-reel tape manufactured and sold from the mid 70s into the 80s. I have never heard of this phenomenon happening with cassettes. The squeakiness you describe in your original post as I understand it is a description of how the voice sounds, not a high-pitched squealing sound that underlies the recording. As you speculate, it seems likely to be an artefact of the batteries dying, although it could be from a poorly manufactured cassette jamming in the machine or too much back-tension at the end of the cassette.

In any case, working with the pitch changing effects seems your best bet at the moment, at least to make the words decipherable.

– Bill

i took it as a change in the voice at the end of the tape
presumably from mechanical issues

as you all noted
we need a better description of the problem
and a sample short clip to listen to