Working on a project to convert 66 r2r tapes(most about 50 years old) to digital. An old Akai r2r player and Audacity have made this a breeze. I have a tape containing my wife’s grandmother talking. It starts out chipmunk speed+ and then over 20 minutes becomes almost unrecognizable because it is so slow. My player appears to be fine, it appears to be recorded that way.
In audacity I can change the speed, but this appears to change a constant to another constant. Since the recording perceptly slows down over time I don’t have a constant speed. Any ideas on how to correct it? I’m using Audacity v 1.2.6 and a newbie not understanding alot about audio tech speak.
Firstly check the tape player. There is a pinch roller that regulates the tape speed, this gets dusty, hard and shiny over time. Clean it with pure alcohol (surgical spirits, IPA, or similar) and allow it to dry thoroughly before putting a tape in. Then test it with a known good tape.
Assuming that you still have the problem, Upgrade to Audacity 1.3.5. It has a feature in the track menu where you can add a “Time Track” and draw a line using the “envelope tool” to adjust the speed progressively. It will be very difficult to get it exactly right, but you should be able to make significant improvements.
Thanks for the insight, very impressive new tool set.
Question on working with the time track and envelope tool - I can change the speed of the track, but because of the drastic difference It will require either doing it multiple times or changing speed on part of the track and then using the time track tool. Is there a way to “multply” the time track effect so that it can slow it down more?
If you click on the “Name” of the time track you will see a drop down menu. There is a menu option to change the “range” of the time track. This brings two pop-up windows, one to set the slowest speed (as a %) and one to set the fastest speed (also as a %).
I’m not sure how well this will work for large shifts in speed - it gets a bit jerky on my machine, but that may be because I have a very old computer. Let me know how you get on.
That worked incredibly well. As the conversation went along the woman’s voice talked about needing to buy new batteries for the tape deck and how playing other tapes on her player were very slow. Since they stopped and started the tape multiple times the speed varied, but with the tools I was able to smooth it out so you can’t tell.