Originally Posted by MoultiPass
Here’s how I would do it in BIAB:


1. Prepare the audio files outside BIAB

Make sure all stems come from the same session:

Same start point (bar 1, or the same pickup),

Same tempo,

Same length / same end point.

If needed, line them up in a DAW (Reaper, etc.), then:

Export one stereo “reference mix” (the full song, or drums+bass only),

Keep the individual stems (bass, drums, etc.) exactly as they are, with the same start.

BIAB will use the reference mix to find tempo and chords, then you will place the stems on BIAB’s tracks.

2. Create the BIAB song and sync the reference audio

In BIAB, create a new empty song.

Set the time signature (4/4, 3/4, etc.).

Set an approximate tempo close to the song’s real tempo (just to start).

Import the reference mix:

Audio > Import Audio (or drag the file onto the Audio track).

Open the Audio Chord Wizard (or Audio > Chord Wizard (Audio), depending on your BIAB version).

In the Audio Chord Wizard:

Locate where bar 1 really starts in the audio (after any pickup/click),

Place bar 1 at that point (Set Bar 1),

Adjust the bar lines so that the main beats in the waveform line up with BIAB’s bar markers,

Let BIAB detect tempo and chords.

When you are satisfied with the alignment:

Transfer the tempo and chords back to the main BIAB window.

Now BIAB’s bar grid, tempo and chord sheet should follow the original audio.

3. Import the stems and generate RT/RD

On the BIAB side:

Keep the reference audio on the main Audio track (optional but useful for comparison).

Import the stems:

Place each stem on its own Utility track (or appropriate BIAB audio track),

Make sure they all start at the same time position as the reference audio (bar 1, or the same pickup beat).

Generate RealTracks and RealDrums:

Choose a style and generate RT/RD tracks at the tempo and with the chord sheet that BIAB detected.

Because the bar grid is now aligned to the original audio, the generated RT/RD should line up with the stems.

4. Check that everything is really in sync

Use the waveform view in BIAB (Audio Editor / tracks window):

Zoom in on the kick drum or strong beats,

Check that the peaks of:

Original drum stem,

Original bass stem,

Generated RealDrums,

Generated RealTracks (bass, etc.)
all fall on the same beats and bar lines.

If things are a little off:

Go back to the Audio Chord Wizard and correct the bar markers,

Or fix obvious tempo detection errors (wrong bar length, wrong first bar).

5. Audition and compare

Now you can:

Mute/unmute original stems vs generated RT/RD,

Compare groove, feel, and arrangement,

Keep switching RealDrums/RealTracks variations while listening against the original stems.

As long as the tempo map and bar alignment are correct, you should see and hear that the main beats are lined up in the waveforms and on the bar grid.

Note: this works best with songs that have a constant tempo or only a few simple tempo changes. For very “live” tracks with a lot of tempo drift, BIAB’s tempo mapping can be more limited, and a DAW with a detailed tempo map may be necessary.

Thanks, this shows how to do it with all original audio generated outside BIAB (original audio and stems). Is it possible to do the same but generating the stems within BIAB? I think the latter is the schenario that has caused confusion (at least for me). It would be good to know if it is at all possible or if the best approach would be as suggested here to prepare all original audio and stems outside BIAB).

BIAB 2026, Studio Pro 8, Song Master Pro, Win11 Home. i7-9700K CPU, 32GB, ESI MAYA44eX, ZOOM UAC-2, Guitar Pro 8, Transcribe, (EZKeys2, EZD3, SD3, EZBass, EZMix3)
Amateur: fiddle, guitar, vocal, beginner on bass.