Quick Audio Mastering with Reaper

In this quick tip, you will learn how to do quick mastering with Reaper. Bear in mind that Reaper still lacks some important features as full-fledged mastering software. However, it has sufficient tools that can transform your ordinary mix into a broadcast-ready song.

Assess the mix before mastering

STEP1.) Check if your mix is ready for mastering. The first step is to load the track in Reaper by going to Insert Media –> then locate the high resolution mix down in your computer.

STEP2.) Ensure that you are working with a 24-bit mix down. Select the waveform and then go to Item –> Source Properties. 24-bit mix down is strongly recommended for mastering. If it’s not 24-bits, you need to do another mix down in 24-bits.

STEP3.) Make sure that the maximum peak amplitude of your mix down is below -3dBFS. Play the song in Reaper from start to finish. Look at the master level meter after finishing the playback. The maximum peak should fall below -3dBFS. If its not, you need to go back to your mix, lower down the master level meters until the desired headroom is achieved. For details on how to prepare your mix for mastering, you can read this tutorial on setting correct audio mixing levels for mastering.

In the above screenshot, the maximum peak level is around -7dB which is OK because its less than -3dB.

Audio mastering steps in Reaper

STEP4.) Mastering is a process. It usually starts with cleaning up the audio, EQ then finally limiting at the last stage. This is the simplest approach. Although mastering engineers often have a lot of additional processes to further enhance the audio; it‘s not included as the scope in this quick tip. Let’s proceed with cleaning up the audio start and end. Go to Edit –> Select all items. Then go to Track –> Envelopes –> Toggle Volume Active. You should see the volume envelopes.

STEP5.) Clean up the start of the audio especially the long silence as well as the end of the audio. You can do this by moving the volume envelope points. This is important because sometimes this will contain some noise which is not part of the song. For more details, you can read this tutorial on Reaper volume envelope.

STEP6.) Mastering effects (EQ, limiter, etc) should be added to your master track. To enable master track in Reaper, go to View –> Master Track. You will then see the master track added to your project.

STEP7.) You can then start adding your mastering effects to the mastering track. Supposing let’s start with parametric EQ. You will use this to adjust the presence, sibilance and bass to your mastered track. To add EQ effect, click FX button.

STEP8.) Using your accurate monitoring environment, sculpt the frequency response to provide the best sounding/flat response. Supposing your mix down lacks mid-frequency and high-frequency response; then you might have the following EQ settings as shown in the screenshot below. It is a good practice that you don’t cut or boost more than 3dB in any frequency bands during mastering. Severe EQ issues can be best fix during recording or mixing. Learn some other EQ mastering settings tips in this tutorial.

STEP9.) You need to get the audio statistics after EQ, you can do this by adding the effect JS: schwa/audio_statistics next to the parametric EQ.

STEP10.) With the audio statistics plug-in added; play the song from start to finish. The plug-in will automatically gather audio statistics data. After completing the statistics at the end of the song; take the average of the RMS total loudness values (L and R). You will need these data to set your limiter. After taking the average, remove the audio statistics plug-in from your master track effects because it’s not needed anymore.

STEP11.) Supposing you target an after-limiter average loudness of -16dB; this varies depending on your loudness expectations. In really loud masters, this can be -12dB and beyond. Take note that as you increase loudness, the dynamics can be affected so set a realistic loudness target that won’t damage the original mix dynamics. The rough formula for limiter threshold would be:

Threshold = RMS total values (average of L&R) + 16dB.

Therefore the threshold settings would be:

Threshold = -27.18dB + 16dB = -11dB

Add a limiter plug-in to your mastering track after EQ; and set the threshold settings. If there is an “out of ceiling” setting (such as Waves L1); set it at -0.3 to provide a little headroom.

As a golden rule, make sure you preserved the dynamics in your recordings. Read this tutorial on how to make radio friendly mixes.

STEP12.) Play the audio in Reaper. Monitor carefully for the presence of distortion, pumping, clipping and severe loss of dynamics in your work. Re-adjust your limiter or EQ settings if necessary. If all are OK, select the final section of your mastered audio. This will highlight only the important sections (see the white background sections on the screenshot below).

STEP13.) If all are set and the sound of your mix down is now big and broadcast ready; render the results by doing a high quality mixdown in Reaper. Take note of the following pointers:

a.) The sample rate should be the same as your source audio (mix down).
b.) The bit depth should still be 24-bits.
c.) When closing your mastering project, do not forget to save it always.
d.) You can re-measure the audio statistics after mixdown using the JS: schwa/audio_statistics plug-in , you have at least attained your target loudness which is near -16dB after limiter.

The resulting 24-bit audio is the final master, keep this as a backup. This is the source file for your distribution either in CD-audio or MP3.

Some tips on distribution

STEP14.)If you want to distribute your masters as MP3, you can read this tutorial on mp3 encoding with dithering and sample rate conversion. This is where you will implement appropriate sample rate conversion or dithering. As a rule of thumb, sample rate conversion should be done before dithering.

If you want to distribute your masters in CD audio format, unfortunately Reaper is not capable to create Red Book CD or burn audio to a CD. In this case, you need red book CD authoring software such as Sony CD architect. For more details, you can read this tutorial on red book CD audio standard.

Content last updated on June 14, 2012