Calculating new BPM once tape speed has shifted....help!

Hello!

I would love it if anyone can help me with this. It’s stopping me importing projects into ableton.

Basically what I’m trying to do is accurately calculate a bpm once i’ve modified the tape speed. So for example. I have a track which is 118 BPM on the OP-1. I shift the tape speed via the white knob to -3. Slow it down a little. I now want to play these 4 tracks recording them into ableton but I don’t know the new bpm to set my ableton project at. I can see after clicking the metronome button that on the right, “T SPEED” is isted at 1:0.8. So I could presume the new bpm is 118 x 0.8 = 94.40 BPM. This doesn’t seem to be quite right. It’s not really on the beat. The other way I have tried to calculate it is when playing back on tape, I can see by holding shift that it displays the tape speed at 84%. So maybe that’s it? I try 118 x 0.84 = 99.12 BPM. I’m not sure this lines up either. Is my maths wrong? Should I be doing it some other way? Maybe I am just terrible at lining up audio to metronome in ableton? Someone help!

Many thanks in advance!

this might help…
http://mp3.deepsound.net/eng/samples_calculs.php

or loop a section of tape on the op1, then use the tap tempo button.

Set the metronome page to beat match with the Green and it will lock the op-1 sequencer bpm to the tape speed,calculating it for you.

don’t count out rounding errors and such too.

Thanks so much guys, Spheric your solution seems to work. @docshermsticks, can you expand on what you mean?