Reel to reel speeds in audacity

I have:
Windows 7
Audacity 2.0.2
Tape recorder/player for only 19 speed
Tapes with 9.5 and 4.7 speed
I have digitalized tape on 19 speed instead of 9.5 or 4,7
How to slowdown speed in audacity from 19 to 9.5 and 4,7?
And how to speed up from 19 to 38.1 ?

Effect > Change Speed. The speeds, at least in the US are all double and half of each other. 15 IPS, 7.5 IPS, 3.25 IPS, etc.

However you are not going to get pure, clear audio. Record electronics and playback electronics are all adjusted for each speed and ideally, the type of tape. If you play a tape at the wrong speed on the wrong machine, all the quality control systems are going to be wrong. If you expect music, then that may be a serious problem. If you just need to understand someone speaking, then it may be close enough.


Effect > Change Speed only for LP’s, not for reel to reel tapes… help with percentages …?

P.s. i use soviet speed standard, not US standards

If you know the original length of the selection and its target length, you can calculate the percent speed change thus:

( ( (original length) - (target length) ) / (target length) ) * 100 = percent change

For example, if the selection is 3 minutes 21.73 seconds and you need it to be 3 minutes 15 seconds, the calculation is:

original length = 201.73 seconds, target length = 195 seconds
((201.73 - 195) / 195 ) * 100 = 3.451%

The calculation works the same if you want to lengthen the selection, just enter the resulting negative value.

Sill no help… I don’t know original length of the selection and its target length…

Here is same as with vinyls: 33rpm played on 45 and recorded, then slowed from 45 to 33 in audacity

I played 9.5cm/s on 19cm/s speed and recorded with audacity…

Help… Here are lots of tapes… with 9.5cm/s speed

So the recording plays much too fast and you need to slow it down to half speed?
(9.5 - 19) = -9.5
(9.5 -19) / 19 = -0.5
((9.5 -19) / 19) x 100 = -50%

When you slow down the digital recording of the tape to half-speed there will be a noticeable loss of high frequency content compared with playing the tape at the correct speed: the slowed digital recording won’t have anything above 10kHz, which is OK for speech but slightly dull for musical performances.

Solved. Thanks.