Bearing Edges -- Drum Sound Physics Part II

In the second installment of this series on drum sound physics I discuss bearing edges and their affect on a drum's performance. Let's see if I can't distill this topic down to the important bits. Come join me!!

0:00 Introduction
2:11 Bearing edge definition and purpose
6:55 Keeping it simple -- two basic types of edges
9:50 Sharp edges
12:24 Round edges
17:10 Roundover edges
20:43 Single cut edges
21:41 Dual/counter cuts
22:13 Effect of edge angle on 'event horizon'
27:05 Effect of edge angle on drum shell mass
28:53 Conclusion

Graphics used for teaching in this video came from:

[ir]

I never understood any of this terminology before. This video is excellent, I now know what people are talking about. Thank you.

[boomerguy]

Wonderful video! I love the way Sonor in their 1982 catalog, has a conclusion that says what we already knew: "One size does not fit all." There is no best choice. Hmmm...doesn't that apply to everything in life?
Even with the very best choices in drum bearing edges, woods and other things, each of us will end up with a favorite choice which has been modified by what we like to do to our drums in terms of size, heads, tuning, sticks or anything else. Still, this was an educational video worth watching.

[mikecrisis]

You’re my spirit animal.
Details details details but you’re ability to not wander too much allows the listener to learn the “why” as well the application.
Bravo!

[Drumma]

Oh the variables! Feels almost infinite when you really think about it. I hope this nerdy journey doesn’t end with just the drum itself, and you end up tackling topics like a drum vs room size and materials, temperature and humidity, etc. You have the insight and use a great approach to deliver the engineering and physics information related to drums. I’ve been searching for this level of detail. Keep it up!!!

[morrinsville]

Thanks for the excellent excellent information, i thought my old 60's drum kit didn't have bearing edges now i know its a vintage round over, I was just about to go get bearing edges cut, but now I have a much clearer idea about the effects!! Very very helpful thank you!

[ardethcain]

Just hanging out in my studio and letting this vid run in the background. Once again... BRAVO! Great info for the masses. Clear, concise and succinct.

[oleran]

Rick Beato should get you on his show. Not only would the discussion be fascinating, but the mannerisms you two share might make for a unique experience for you both.

[miked]

I'm loving this series mate.. I just got into building a unique type of stave shell so your information is invaluable.. cheers

[tommyp]

The Einstein of drum physics, great content!

[JohnJohnson-rcci]

Ok Joel. Good work. Further to the Sonor Signature Series and Designer Series Kits the bearing edges are 45 degree sharp on the outside edge of shells, these edges are very sharp. I believe this coupled with the very thick shells is what gives these drums their very distinct sound. This has been an interesting listen. Thank you. Shalom.

[bowiemusic]

Great. I appreciate your analytical approach and break down of the details of how drums are made and the impact on the sound. Thanks.

[EricT]

Loving these videos - actual facts and the science behind it instead of the folk "wisdom" that surrounds these complicated instruments.

[davidepolitti]

I was looking forward for the next episode of the series! Keep it going!

[TomCawoski]

Very good explanation of drum bearing edges!!! You mentioned about tuning issues with bearing edges that aren't true. How would you describe the sound (excessive overtones) of a drum/tom that may have a bearing edge that isn't correct and how bad would it have to be before you would modify the edge to correct the problem or have someone do it for you? I was taught to never modify the bearing edge in any way. Thanks for another great video!!!

[reverendobrown]

Great video, straight to the point, sufficiently detailed but not too on!!

[EversonBernardes]

The drumhead contact with a shallow angle edge cut will not only bleed off more energy to the drum shell as you mentioned (obviously, dependent on the mass of the shell), but it can also introduce a waveshape distortion to the drum sound.

Think of it like this: the head vibrating pattern is essentially a complex sine wave, fundamental note overlapped by a series of harmonics. That contact limits the motion in one direction, flattening the apex of the wave asymmetrically. The edges of the head have a larger proportion of high order harmonics (i.e. mic the edge vs. the center of a head and you'll get two very different harmonic profiles), so you'll distort most there, creating a bunch of additional new harmonics.

That will probably be heard as a louder, brighter "crack" on stronger hits followed by a faster decay and "deadening" of the sound.

EDIT: create a playlist for these physics videos! Better to have them automatically play one after the other.

[AndrewDrummer-uu]

I learnt a great deal again I can't thank you enough see you next time brother

[willymccabe]

This was super informative!! Great video. Finally someone took the voodoo out of bearing edges!

[paulblahuta]

Hey, very interesting to know. Appreciate the physics around your approach buddy.

[drumminjesus]

Great info, I am enjoying this learning process. Thanks!