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Synth overlay

The Soundslice synth overlay feature lets you hear synthetic playback and real playback at the same time. Here’s why that might be useful for you:

  • When transcribing, this helps you check your notation’s accuracy against the source recording. It’s great for verifying your transcriptions are correct, both in pitch and in timing.
  • When learning/practicing, this lets you play selected notation over an existing recording. For example, you can play a synthetic soprano part over a real backing track, in cases where you don’t have a real performance recording for the soprano part.


Synth overlay is available in our player in two cases:

  • If you’re in edit mode for a slice you’ve created yourself, synth overlay is always available.
  • If you’re in view mode, synth overlay is only available if the slice owner has opted into making the feature available via the advanced slice settings.

Also, it’s only available if you’ve selected a real recording for playback. If you have synthetic playback active, synth overlay wouldn’t serve much purpose.

Activating synth overlay

To activate synth overlay, open the recordings menu at the bottom of the screen. You’ll see a “Use synth overlay” checkbox there:


If you check this box, playback will use your selected real recording plus synthetic playback on top of it.

You can toggle this on/off at any time, and it works with any type of recording: MP3, YouTube or other video. It also works if you’ve changed playback speed or have an active loop.

Controlling synth overlay volume

You’ll probably want to tweak the volume of the synth overlay, to find a sweet spot between “Loud enough that I can hear it” and “Soft enough that I can still hear the original recording.”

Change the volume via the volume controls in our player, described on this separate page. If synth overlay is active, you’ll see separate volume controls for “Recording” and “Synth overlay”:


Controlling synth overlay instrument sound

Synth overlay uses whatever your slice specifies as its synthetic instrument sounds. But depending on the timbre of your music, you might want to change the synthetic instrument sound to make it easier to compare.

Here are two ways to do that:

  • The fastest way is to activate the real synth (not the synth overlay) and open the volume controls (see here). You’ll be able to change each instrument’s synth sound from this single screen.
  • You can also do this by editing an instrument and changing its synthetic sound there. (This option will only work if you’re the slice owner.)

Synth overlay and multi-part music

Does your slice have multiple instruments? No problem.

By default, synth overlay will play all instruments’ parts from your notation. If you’d like to mute certain instruments, use the per-instrument volume controls in our volume controls. Note you’ll have to temporarily switch to synth playback in order for those per-instrument volume controls to be available.

How is synth overlay different than normal synth playback?

The main difference is that it uses the timing from your current recording’s syncpoints instead of its own synthetic (perfect) timing. This is what makes it possible for the two audio tracks to line up — hence making it possible for you to aurally compare them.

Why don’t I see the “Use synth overlay” checkbox?

See the Availability section above.

How do I enable synth overlay for people viewing my slice?

That’s in the advanced slice settings.

Is there a keyboard shortcut for toggling synth overlay?

Not by default, but you can indeed add a custom one for it within our editor. See Customizing keyboard shortcuts.

I enabled synth overlay and the playback doesn’t line up! What should I do?

Here are a few things to check:

  • Make sure your syncpoints are as accurate as possible. You might want to drag certain ones left or right, making micro adjustments. Synth overlay uses your syncpoint data to know when to play the synthetic sound — so this is within your control if you’re the slice creator.
  • If you’re using YouTube, sometimes there’s a slight delay due to YouTube buffering. This commonly happens the very first time you hit Play after loading the page. In this case, try pressing Pause, then Play again, and it might work itself out.
  • If all else fails: are you sure the timing in your transcription is correct? ;-)