How to slow down audio file as if it were tape in Cubase

I am digitizing some old 1/4" mono recordings.

My tape deck’s slowest speed is 7.5 ips but some of the recordings were clearly recorded at 3.75 ips and therefore are double speed and up an octave when I attempt to play them.

So how do I create a double-length audio file at the correct pitch in Cubase 10?

Obviously I can do a pitch shift and then a time-stretch - but is there a method of simply slowing the whole thing down by 50% in one hit? - there should be no need for resampling or interpolating old material - just padding the bit stream would do it… But is that possible in Cubase?

By the way these recordings are around 45 minutes each - so not short wav files.

You could digitize it, then edit the header on the audio file to halve the sample rate.

If you’re wanting to render/export the resulting file then you’ll have to resample somewhere along the line i think.

A quick way is to select the waveform, go to Audio Menu, Processes, Resample and use the difference control to get what you want, and it will auto process the audio as you try different rates. Not sure what quality you’ll get though, depending on your record sample rate.

The other option is to import/record the audio into your project with the project sample rate set at 88khz (Project > Project Setup > Record File Format) if your hardware supports this. Then once you’re done drop the sample rate of the project to 44khz and chose to NOT convert the audio files.

One other option is to time stretch in Cubase to double as you’re doing and then select ‘elastique pro-tape’ mode as the Algorithm, when you stretch a waveform in tape mode cubase won’t try to retain it’s current pitch/octave.

Audacity is probably the better choice for this kind of task however as it’s a direct sample editor.

Another way: You’d lose a generation but you could dump it into Cubase at 7.5ips. Then switch your tape speed to 15ips and record it back onto tape. Then switch tape speed back to 7.5ips and play it back into Cubase.

There are more than one VST for this. An example is https://www.pluginboutique.com/product/2-Effects/35-Pitch-Shifter/2173-Tape-Stop

Also Vinyl by Izotope might be all you need. https://www.izotope.com/en/products/vinyl.html

Some options:

  1. If you change the time stretch algorithm to ‘Elastique Pro - Tape’, you can then use the time stretch tool to double the length of your audio file. This should give the result you’re looking for.

  2. Use the Cubase Pitch Shift processing window to shift the file down one octave but UNCHECK the ‘Time Correction’ option.

  3. Record the file at a high sample rate (e.g. 88.2kHz) and then change your project sample rate to 44.1kHz. Now you have a ‘44.1kHz’ file playing at the correct speed.

Loopmash, the effect plugin, does have tape stop, and different tempo options - not sure if this is what you’re looking for, but it does work.

Thanks for all the replies - I found a different workaround which is actually really easy, and onboard Cubase without making any odd adjustments…
So I thought I’d share in case anyone else needs to do anything similar…

  1. Add new sampler track
  2. drop the entire recording from piano roll into sampler
  3. create a midi region
  4. draw a note at C2 (one octave below default pitch) - and increase it’s length to double the length of the recording
  5. Either render in place - or export as wav

Worked perfectly!

Yes, but this way your are actually resampling the content which deteriorates its audio quality to a certain extent. Therefore, I consider the third suggestion made by J-S-Q as the best one since it does not involve any resampling:

This is basically equivalent to what has been suggested by GlennO:

Best regards

Miloslav

Thanks Miroslav - yes I see what you mean. Very fair point.

Frankly these 1960s recordings are not good enough to worry too much about that detail - and even the bias differences between the tape machines (the old domestic flat-deck ones vs my Revox running at the wrong speed!! ) are probably affecting EQ curves a bit.

So my trick of playing a sample out of a sampler an octave down is definitely the quickest dirtiest way of doing this without too much extra processing or loss of quality. I can do the whole process in about 10 seconds (not including the rendering time)

I used Izotope RX 7 to get rid of motor rumble and other extraneous noise.

The results are audibly pretty damn good under the circumstances.