Andy
Honorary Member
OK, I feel compelled to post this up. I know it theoretically should be in the drums section, but I believe it to be of general interest.
Over the last couple of years, amongst many other things, we've really been digging into drum depth, & bass drum depth specifically. Everyone has their preferences, but there are some misconceptions touted as good advice, & through experimentation + testing, I want to put some of those misconceptions to bed. I'll try not to get too far into the science
Popular thinking is that a deeper bass drum delivers more bottom end. In some circumstances that can be true, but only to a point. Some think the reverse is true, & that's correct too, but as always, these individual factors need to be taken in context, & really, it's context that this thread is all about.
The basics:
All other elements being equal, the more shallow the drum, the nearer to it's fundamental the resultant sound will be. In a shallow bass drum, harmonics and inharmonic overtones are still produced, but are at a lower amplitude compared to deeper drums. Essentially, there's less space for them to establish, & less shell area available to augment the sound. As the fundamental is the lowest meaningful frequency the instrument can produce, it manifests itself as a clean "bottom end". This uncluttered sound has more of a clean note impression to it, & is therefore usually easier to distinguish in the mix too, but can sometimes be a bit "thin".
A deeper bass drum produces more harmonics & inharmonic overtones. An increase in harmonics can offer a "fattened" sound, rather like adding a chorus to a bass guitar (not an exact analogy). An increase in inharmonic overtones however starts to detract from the bottom end. Eventually, if the drum is deep enough, those inharmonic overtones can dominate and the result is often a nasty metallic sound. Dampening can reduce such inharmonic overtones, but it also diminishes harmonic overtones that are widely regarded as beneficial to a nice fat weighty sound.
Thickness:
Usually adds mass & rigidity, but not in every construction. Similarly, a thicker shell usually resonates less, but again, not always. A thicker shell will deliver the fundamental more effectively, but often stifles harmonics at the cost of increased inharmonic overtones.
Resonance:
A highly resonant shell often delivers the fundamental less effectively, as it promotes development of harmonics but also slightly sharp or flat harmonics, these being perceived as the "character" of the drum. A resonant shell usually produces less inharmonic overtones, but only when correctly aligned to mass. A high mass/rigid shell delivers the fundamental more effectively, but with the negatives mentioned under thickness.
Bearing edges, tuning, head choice, etc, all have a profound affect on the resultant character, but I'm concentrating on the non variables - the foundation of your bass drum sound. I'm also relating the following to the more commonplace ply shells. Solid shells can behave differently, & offer exceptions that can be exploited.
Deeper bass drums generally benefit from having a thicker shell. This allows for more efficient delivery of the fundamental, but usually requires more muffling to control inharmonic overtones. Such a setup is better suited to those wanting punch, presence, & projection. More shallow bass drums usually benefit from a thinner shell. This allows for more harmonics to be generated, & greater resonance usually sharpens/flattens those harmonics to produce a more wholesome sound.
A more shallow thin shell bass drum will generally produce more bottom end than a deeper thicker shell bass drum.
Extremes:
Any bass drum of square dimensions or above will produce excessive inharmonic overtones, almost irrespective of construction. The result is weak delivery of the fundamental and a confused voice that detracts from the lower frequencies. A bass drum who's depth is half or less of it's diameter will deliver the head fundamental with few harmonics or inharmonic overtones, due to reduced shell involvement. The result is a thin sound, but one that will effectively sit separately in the mix.
These are the basics, & assume an industry standard ply shell construction. Solid shells can be used to substantially augment the basics, but only to a point. Similarly, wood species can have some affect too. As with all drum constructions, all elements of the specification must be taken into account, as very little in isolation has meaning, but I thought I'd concentrate on depth & thickness, as they're the two subjects that crop up the most.
I hope some of you find this of interest, especially if you're soon to make drum choices.
Andy.
Over the last couple of years, amongst many other things, we've really been digging into drum depth, & bass drum depth specifically. Everyone has their preferences, but there are some misconceptions touted as good advice, & through experimentation + testing, I want to put some of those misconceptions to bed. I'll try not to get too far into the science
Popular thinking is that a deeper bass drum delivers more bottom end. In some circumstances that can be true, but only to a point. Some think the reverse is true, & that's correct too, but as always, these individual factors need to be taken in context, & really, it's context that this thread is all about.
The basics:
All other elements being equal, the more shallow the drum, the nearer to it's fundamental the resultant sound will be. In a shallow bass drum, harmonics and inharmonic overtones are still produced, but are at a lower amplitude compared to deeper drums. Essentially, there's less space for them to establish, & less shell area available to augment the sound. As the fundamental is the lowest meaningful frequency the instrument can produce, it manifests itself as a clean "bottom end". This uncluttered sound has more of a clean note impression to it, & is therefore usually easier to distinguish in the mix too, but can sometimes be a bit "thin".
A deeper bass drum produces more harmonics & inharmonic overtones. An increase in harmonics can offer a "fattened" sound, rather like adding a chorus to a bass guitar (not an exact analogy). An increase in inharmonic overtones however starts to detract from the bottom end. Eventually, if the drum is deep enough, those inharmonic overtones can dominate and the result is often a nasty metallic sound. Dampening can reduce such inharmonic overtones, but it also diminishes harmonic overtones that are widely regarded as beneficial to a nice fat weighty sound.
Thickness:
Usually adds mass & rigidity, but not in every construction. Similarly, a thicker shell usually resonates less, but again, not always. A thicker shell will deliver the fundamental more effectively, but often stifles harmonics at the cost of increased inharmonic overtones.
Resonance:
A highly resonant shell often delivers the fundamental less effectively, as it promotes development of harmonics but also slightly sharp or flat harmonics, these being perceived as the "character" of the drum. A resonant shell usually produces less inharmonic overtones, but only when correctly aligned to mass. A high mass/rigid shell delivers the fundamental more effectively, but with the negatives mentioned under thickness.
Bearing edges, tuning, head choice, etc, all have a profound affect on the resultant character, but I'm concentrating on the non variables - the foundation of your bass drum sound. I'm also relating the following to the more commonplace ply shells. Solid shells can behave differently, & offer exceptions that can be exploited.
Deeper bass drums generally benefit from having a thicker shell. This allows for more efficient delivery of the fundamental, but usually requires more muffling to control inharmonic overtones. Such a setup is better suited to those wanting punch, presence, & projection. More shallow bass drums usually benefit from a thinner shell. This allows for more harmonics to be generated, & greater resonance usually sharpens/flattens those harmonics to produce a more wholesome sound.
A more shallow thin shell bass drum will generally produce more bottom end than a deeper thicker shell bass drum.
Extremes:
Any bass drum of square dimensions or above will produce excessive inharmonic overtones, almost irrespective of construction. The result is weak delivery of the fundamental and a confused voice that detracts from the lower frequencies. A bass drum who's depth is half or less of it's diameter will deliver the head fundamental with few harmonics or inharmonic overtones, due to reduced shell involvement. The result is a thin sound, but one that will effectively sit separately in the mix.
These are the basics, & assume an industry standard ply shell construction. Solid shells can be used to substantially augment the basics, but only to a point. Similarly, wood species can have some affect too. As with all drum constructions, all elements of the specification must be taken into account, as very little in isolation has meaning, but I thought I'd concentrate on depth & thickness, as they're the two subjects that crop up the most.
I hope some of you find this of interest, especially if you're soon to make drum choices.
Andy.