Quick and accurate locking grouped audio stems recorded w/o a click track to a fixed tempo

Cubase
1

Hi everyone,

I am learning how to use Cubase Pro 15. In my usual workflow there is one task that drives me crazy and takes me a lot of time, because I do not know how to do it in a simple and fast way.

What I need is to convert audio stems — for example vocals, drums, bass and other instruments — from songs performed live, without a fixed tempo, where the drummer/percussionist did not use a metronome click, into stems that are strictly locked to a specific, consistent tempo throughout the whole song.

I am convinced there must be a much simpler and faster way to do this than the method I am currently using, but I have not been able to find it.

So far I have tried the following:

  1. Detecting the closest approximate global tempo. This does not work very well because there may be significant tempo changes throughout the song.
  2. Grouping the stems with “=” so that they can all be edited together.
  3. Activating Free Warp.
  4. Using the drum stem to adjust the audio alignment to the tempo.
  5. If the drum stem is in 4/4 with the snare on beats 2 and 4, using the snare as a guide. The problem comes with more complex drum parts and time signature changes.
  6. The problem also appears when the BPM variations in the stem are significant.

Even when everything goes well, it still takes a lot of time and work. I am convinced there must be a fast and reliable way to do this without audio artefacts or tempo errors.

What I have in mind is something like this:

“Automatically detect all tempo changes and assign them to the corresponding points in the stems, then change everything to, for example, 100 BPM, so that all points are converted to 100 BPM and the audio stems are properly aligned to that click, without having to edit every single point manually.”

Does anyone know how to do this in Cubase Pro 15?

Thanks in advance.

2

If there are significant variations in the tempo for the original tracks, you’re not likely to get them locked to a single fixed tempo very easily, and anything you did that might seem to try to do that quickly would likely result in the tempo being off, possibly significantly, in at least some parts of the song.

The way I approach this sort of thing – and I should note that I’m usually doing it with MIDI tracks, not audio, for example because I want to start sketching out a song by just playing a piano accompaniment, and I don’t want to do that with a metronome or click track is because part of the reason I’m doing this is to see where the tempo goes naturally when I play the song (I’m usually singing at the same time, too, though I don’t record that) – is as follows:

First, once the track is recorded, make sure and set it in time mode, not musical mode. (At least for MIDI tracks, and with whatever default preferences I have set in Cubase, MIDI tracks always default to musical mode.)

Second, use the Time Warp tool to align measures (and/or finer gradations) to the actual playing. If the tempo doesn’t vary too widely, it will help to set a tempo that is somewhere in the ballpark of what was played as a starting point since that may get the measure boundaries to at least be closer to where they ultimately need to be. If the tempo is fairly steady, it may be good enough to do this for some large number of bars – maybe even just the start of the song (not including pickups that come before the first downbeat) and the end of the song. However, most of my stuff varies quite a bit in this scenario, so I’m usually doing it every 2-8 measures as a starting point, except for areas with speedups or slowdowns, where I’ll probably at least get it down to one bar, and maybe even finer gradations if the change in speed is gradual.

While doing the above, I’m generally playing the track back with the click active so I can hear if things are mapping out pretty reasonably. At this point, though – “Third” – I’ll go through the entire song and refine any areas where things get off to any noticeable degree.

Fourth, at least after saving and backing up the results to this point, if I don’t want to just go with the tempo map I’ve just created (which is pretty much always the case – I want to at least smooth out the variations, though not necessarily to create a fixed tempo), I set the tracks back to musical mode, then edit the tempo track directly to set specific values and delete entries between desired tempo changes. I may do some math before doing this, for example tofigure out what the average tempo was. (If you did the whole song in the first step, you’ll likely get that from the tempo map itself at that stage.)

In my scenario, I’m not going to use the original scratch track. I’m just using it to map out the song structure and establish a tempo map for recording the real tracks. However, as long as you’re not making to severe of changes that would lead to audio artifacts, and you’ve made the tempo map conform to the actual playing sufficiently tightly, I don’t see why this couldn’t also work for your scenario.

One additional thought for your scenario, and this comes into areas I have not tried. If you’re extracting drum tracks as audio, could you use audio-to-MIDI conversion – maybe just of the kick or kick and snare, to use for building the tempo map? Perhaps that might give better odds of using any automated tools for this sort of thing than working with more complex portions of the audio? (I’ve never had any luck with automatic tempo detection for my scenarios, but, if I’m doing it with audio, I’m probably doing it with a full mix to use for practicing or something, or maybe as a guide if I’m recording a song based on a demo that I only have as audio.)

3

Thank you very much for trying to help.

Yes, that is quite close to the kind of workflow I am already using, although in my case I am working with audio stems, not MIDI. I should also have mentioned that, before doing the tempo-mapping work, I keep the audio tracks in linear/time mode rather than Musical Mode.

What I am trying to do is this:

I have several audio stems from the same live performance — for example drums, bass, vocals and other instruments. The performance was recorded without a click track, so the tempo is not fixed. It may drift, for example, between 97 and 105 BPM simply because it was played live.

My goal is not only to create a tempo map that follows the original performance. What I need is to take that variable-tempo multitrack audio and conform all the stems to one strict fixed tempo, for example 100 BPM, while keeping all stems perfectly aligned with each other.

The manual sections I have been looking at are mainly:

  • Tempo Matching Audio
  • Matching Audio to the Project Tempo
  • Extracting a Tempo Definition Grid from Audio
  • Free Warp
  • Tempo Detection
  • Time Warp
  • Set Definition from Tempo

So far, the only reliable method I have found is still quite manual: create or correct the tempo map, use the drum stem as the main reference, and then adjust warp positions — sometimes only using the snare on beats 2 and 4 as a practical guide. This works, but it takes a lot of time per song, especially if the tempo changes are significant or if the drum part is complex.

What I am trying to find out is whether Cubase Pro 15 has a faster and more automatic workflow for this specific case:

  1. Detect the variable tempo of the original audio performance.
  2. Create the corresponding tempo definition/tempo map.
  3. Apply that information to a group of aligned audio stems.
  4. Then force/conform the whole set of stems to one fixed BPM, such as 100 BPM, without having to manually edit every warp point one by one.

Is there a proper Cubase workflow for doing this with multitrack audio stems, not MIDI and not just short loops?

Thanks again.

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4

Have a look at this video:

Creating the tempo map usually takes the longest and the more accurate you are the better the result. The rest is done very fast.

5

FWIW, I understood what you were trying to do, but I’m pretty sure the manual tempo map creation is needed – i.e. “the nature of the beast” – and that will be similar for both MIDI and audio as the freely-tracked content. (The setting it to time mode instead of musical mode may not be necessary for audio if time mode is the default for audio.)

The video Johnny linked is an excellent tutorial on this. (I’d forgotten about it, but I had seen it before, though I originally learned the method from another video.) The one thing I wasn’t aware of (for audio specifically) starts around 10:30 in the video, where he tells Cubase the audio was tracked to the tempo map that you’ve manually created prior to simplifying the tempo map you’ve just created. (This part happens automatically with MIDI when I switch it back to musical mode.)

Early in the video he shows a potential shortcut for this, but he ultimately discards it and does the mapping manually – the shortcut he shows just gives him a starting point for the tempo that makes it a little quicker to set up the manual tempo map.

This is the part you really need to do manually. However, depending on how steady the tempo in your source tracks is, you may be able to do it more or less granularly – this is what I was alluding to when talking about doing it every few measures, but then correcting things on a more granular basis if needed. Dom shows this in the video, too, though he seems to adjust things every measure.

This is the part I was missing due to having only worked with MIDI, but he discusses at the point in the video I mentioned above.

I alluded to this part – basically just deleting tempo markers – and he showed that in the video a bit after the time stamp I mentioned – the part I was missing is mandatory before doing that.

6

Hi Johnny!

This is what the doctor ordered!

This unknown funtion (for me) “Set Definition from Tempo” and the easy and fast workflow: “Tempo detection => Warp Grid => Set Definition from Tempo” is the solution that I was looking for. Thanks!

On a side, for sure, manual adjustment will be the best way to fix the tempo. Absolutely true, but it is time consuming and not always we work on something that requires that effort. In this case, the tempo detection, some few changes and fix the tempo map with Set Definition from Tempo is the solution. For me it has been a hidden treasure until now!

On the other hand, patient manual work on stems like the example that Dom Sigalas said (old live record or preparation for later work) is the other way and also another hidden gem.

Once again a big thank you for your help.

7

Personally, that video for all it’s good intentions is useless in some scenarios. There are a couple of critical pieces of info left out in the first minute or so (as I remember from when I first tried to follow it a few years ago).

I figured things out after a bit of head scratching at the time and chalked the omissions to assumptions made in the video.

At any rate, if the op yanks all the live tracks to a fixed grid, he’s gonna say “yay”…but likely blind to anyone else then commenting “dude…this thing now sounds like canned karaoke territory”…imo.

When I do these types of projects on live stuff, I might align the drums only…and then listen to the other stuff. Maybe nudging a bit…maybe not…point being the 8 guitar players and 6 bass guitar players :slight_smile: were …at the gig…mentally locking their very-human playing to the vibe and the drummer. Which…imo…may just well be vital to the result, even with a gridded drummer.

The limit will likely be the op saying “hey, I don’t have patience to do it that way”. :slight_smile:

8

Thanks for your help, Rick!

I guess that this matter is explained and I am pretty sure that I am not the only one looking for it.

Thanks for your help.

9

Hi Dos,

I guess that the video shows the methodology. I agree with you that, in most cases, a kind of freedom is desirable but, when I have to work with some stems to fix the song to a specific tempo this method works better than my previous one that was absolutely manual (precise but time consuming).

So, with this method now I can decide how to do it and how many minutes/hours I want to work on it. For me, it is a great discovery.

10

There is no single thing on Earth ever created by a human being where all other human beings agreed upon. Why does it have to be different here?
Somebody asked for a hint on how to go about a certain task. The video is very likely to give them that hint. Turns out that it actually did.

If it doesn’t work for your scenarios then I hope you’ll find a fitting workflow. And if you do and the workflow involves Cubase it would be dandy if you can lay it out here or even make a video about it.

11

Hey, what can I say… the video title is “this is the real secret”…and it wasn’t in my case :slight_smile:

So, yes, you have a point…Dom’s video is the real secret unless it isn’t :slight_smile: