22. When I record audio in PowerTracks, why does it not sync up with my other audio or MIDI tracks?

Identify if the problem is that (1) a MIDI track is consistently out of sync by the same amount throughout your song, or (2) your MIDI and/or audio tracks drift out of sync over time.

(1) MIDI track is out of sync by the same amount throughout your song

You might be using a software synthesizer such as the Roland VSC or Microsoft GS Wavetable for MIDI playback (check this in Options | MIDI Devices). Software Synthesizers usually have noticeable latency because the sound is processed by your computer's CPU before being sent to your sound card. This means that there is a delay between when PowerTracks sends the MIDI data and when you hear it played. There shouldn't be a problem if you are consistently using the same MIDI Output Driver, but if you are having trouble syncing audio and MIDI there are a couple of settings in PowerTracks that you can use to correct the problem:

  • The Audio I/O Delay setting in Options | MIDI Devices. This will delay the start of audio playback and audio recording, which is useful if you want to attempt to keep audio playback/recording in sync with MIDI, especially if you are using a software based synth for MIDI playback. Normally, you will set this to match the Synth Output Latency Delay. If you are finding that the audio comes in before the MIDI (MIDI is slower), increase this setting. The audio will be delayed by the amount in milliseconds that you specify. You may have to experiment a little to find exactly the correct delay. Note that while the Synth Output Latency setting should normally be set to the same value as the Audio I/O delay, the Synth Output Latency setting is quite different; it is only for keeping the visual display, such as displayed times and highlighting of notes, in sync with MIDI playback. It doesn't have any effect on what you actually hear.

  • The Offset In MS setting in Options | Preferences | Audio can be used to make an adjustment to the timing for the purpose of keeping the MIDI and audio in sync. You can make an adjustment to this setting if the sound card's audio timing is early or late in comparison to the MIDI. For example, if the sound card's audio is being heard later than the MIDI, you can try increasing this setting, which will delay the MIDI timing to match the Audio timing. The default for this setting is 0.

Note:

*If you are using the Roland VSC as your MIDI Output Driver, you can adjust the VSC's response time in the VSC Settings window: Open the VSC panel, click on the Setup button, and click on the Performance tab. You may be able to get it down to slightly below 100 ms without experiencing any audio glitches, depending on the speed of your computer.

*If you have PowerTracks Pro Audio 9 or higher, you may want to consider using the VSC-DXi rather than the stand-alone VSC. In general, the DXi version is better to use when working with both MIDI and audio.

(2) MIDI and/or Audio tracks drift out of sync over time

If you are only working with audio, or your tracks don't remain consistently out of sync by the same amount as described above, check to see if you are using more than one sound card. In other words, are you are playing back different tracks through different sound cards? It is possible that the clocks on your sound cards are not perfectly in sync.

There are two places you can choose your audio drivers:

  • In PowerTracks Pro Audio: Options | Preferences | Audio | [Drivers].

  • In the Windows Control Panel: Multimedia (Win 98/ME), Sounds and Multimedia (Win 2000), or Sounds and Audio Devices (Win XP), in the Audio section.

In PowerTracks, if you have "Microsoft Sound Mapper" selected as your audio driver, PowerTracks will use whatever is selected in the Windows Control Panel. If you have a driver *other* than the Microsoft Sound Mapper selected, PowerTracks will use that driver. Make sure you don't have the Sound Mapper selected in addition to another driver. To correct this problem, you will most likely need to use a single sound card for audio playback.

Another thing that we have encountered that might cause tracks to drift out of sync, is if the sound card is recording and playing back at different sample rates. This seems to be a somewhat common issue with some SoundBlaster cards. The first thing you can try is to set PowerTracks to 48 KHz sample rate, which is done in Options | Preferences | Audio (File type pull-down). If that doesn't help, take a closer look at your sound card's software and make sure that it is set to the same sample rate as PowerTracks.

If that doesn't help, follow the suggestions in FAQ 87 for improving audio performance on your computer.


Alyssa - PG Music