Converting Higher Quality Audio to
16-Bit/44.1 kHz for CD-Burning

By Scott Stepenuck , Senior Technician

With today’s audio cards, it’s very common to have analog to digital and digital converters (A-D / D-A) that can handle higher than CD quality audio. Recording at bit and sample rates greater than 16-bit/44.1 kHz will provide you with higher quality recordings, however at this higher resolution, your mixed down files can’t be burned to audio CD. This month’s tech tip answers the following question:

How do I burn my project onto a CD if I used higher* than 16-bit, 44.1kHz audio?

We can accomplish this in SONAR (or Guitar Tracks Pro, Home Studio 2002, Home Studio XL, and Pro Audio) using an undocumented feature that draws upon Windows ability to convert sample rates using components built into the operating system. To do so you will need to be familiar with your sound card control panel, and SONAR's audio options.

One thing to keep in mind is that once you begin a project, you can not change the sample rate and bit depth of that project, you must decide on an appropriate sample rate / bit depth before hand. If you are transferring audio from a DAT or ADAT format tape, 48 kHz is very common.

This is an important consideration that cannot be overlooked. The sample rate in your sound card control panel MUST match the sample rate specified in SONAR. If this is not properly set prior to your actual recording into SONAR, your audio will not be salvageable through this process.

OK, now for the fun. Let’s begin.

1. Once your project is complete, you need to bounce everything down to a single stereo audio track. This is done from the Process Menu, selecting Bounce to Track(s).
2. Next, we need to export our mixed down track using the Export Audio function (found in the File menu)
3. In the Export Audio dialog be sure to choose 16-bit for the file bit depth.
4. After exporting the audio, close SONAR and open up the sound card control panel (for Midiman cards, usually the Delta Control Panel, for Echo Audio, usually the Echo Console, for MOTU it's the 324 console, etc.) Once the control Panel is open change the setting for your sample rate to 44.1 kHz.
5. Next launch SONAR and go to the Options menu and select Audio. In the General section change the Audio Driver Bit Depth to 16 bits. Change Default Settings for new projects to 16 bits and 44.1 kHz for the sample rate.
6. After making these adjustments, run the Wave Profiler**.
7. Create a new project. From the File menu, select New. The Normal option is fine for this.
8. Import the mixed down audio from the File | Import Audio command menu.
9. Confirm the bit depth sample for the file from the File menu, selecting Info, and clicking on Stats.  It should state the correct sample rate bit depth.
10. After you have done this you are ready for the final step.  Again, we need to use the file export audio command.  Be sure to select 16 bits for the Bit Depth and uncheck all Mix Enables.

This completes our conversion. You are now ready to burn you mix onto a CD using Cakewalk pyro or other CD burning software.

*Please note you will achieve better results when converting audio from 96 kHz to 44.1 kHz as apposed to 48 kHz to 44.1 kHz. You may find, depending on your source material that going from 48 kHz to 44.1 kHz may introduce noise into your final mix. This may need to be further processed through some form of noise reduction, be it an external editor, a DirectX plug in, or a hardware-based unit.

**Note: In some instances, with certain audio hardware configurations you may be prompted with an audio driver error dialog during this process. This is nothing to be concerned about. You will have to exit SONAR, re-launch, and verify these settings, repeating as necessary.

When you can successfully run the wave profiler without an audio driver error, you are ready to proceed.

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