The Beat Detective Hack!
Time correction on your drum tracks can be a can of worms. There are many arguments for and against editing your drums, as well as a multitude of different techniques you can use to achieve the “performance” you’re looking for. Today, I want to specifically focus on Pro Tools’ “Beat Detective” and its functionality and a few tips on improving performance.
Here is a quick rundown of “Beat Detective” and its functions. For those who are familiar with Beat Detective, please feel free to scroll down past the summary to the HACK.
Beat Detective will analyze the transient (hit) points and generate separation markers on your audio regions.
It can then separate the region and allow for it to be time corrected.
Your separated regions can now be corrected or “time aligned” to your taste.
How heavily it should be corrected to the grid is up to the taste of the producer/engineer/artist or the context and genre of the song
Now that your regions have been chopped up and moved, there will be dead space and gaps which will cause glitches and silence around the separation points
By filling the gaps and cross-fading, beat detective can smooth out many of the “glitches” that the time correction has caused
Make sure to listen through the tracks carefully even after the detective has done its thing. While it is effective, there will almost always be a few spots where there are still artifacts from the editing.
Beat Detective is a very useful tool for drum editing. However, this sleuth is not without problems and makes its fair share of mistakes. One of the common issues is mis-identifying the transient points during its analysis for region separation. Since drums are typically recorded with multiple microphones, Beat Detective’s algorithm will focus on whatever it deems to be the most “obvious” transient.
Here is a situation where Mr. Detective has identified the Snare drum correctly (click on image to see enlarged view):
Here is a situation where it is identified incorrectly (click on image to see enlarged view):
I don’t have a technical explanation as to why there are incorrect analysis points (a question for the much more qualified programmers at Avid), but in my estimation there is too much information for the detective to analyse. The milliseconds of delay between close mics and ambient mics also contribute to this. In this example, I have grouped all the drum mics together to be analyzed (named “Main Drums), so the points have been generated based on all the mics including Multiple Close Mics, Overheads, Stereo Rooms, a Back Iso Room, and even a Hallway closer to the parking lot than the drums!
Here is a LIFE Beat Detective hack! Instead of grouping all the microphones of the drums together, create a separate group specifically for the analysis of the region separation. Depending on the song or the section of the song, pick 2 to 4 of the most prominent instruments to include in this group. I usually name this group “BD”. In this case, I used 3 microphones: “Kick In”, “Snr Top”, and “High Hat”. Temporarily turn off your “Main Drums” group, select the “BD” group and analyze. By feeding the algorithm less information, we can allow it to identify the transients more accurately. Once you have all your edit points, turn the “Main Drums” group back on, select the regions and separate.
While this little trick will cut down on the number of wrong analysis points, it is not foolproof, so you will still have to be careful of mistakes. As well, if there are other drums that are not in your “BD” group, you will have to manually add the analysis points in.
I hope this makes your editing life a little bit easier! I would love to hear any other tips and tricks you may have for Beat Detective and editing. And please don’t hesitate to reach out to me for clarifications, questions, or to point out anything I’ve overlooked or made mistakes on.
Also, video version of this tip to follow!