Drum Size Question

Hollywood Jim

Platinum Member
I have been shopping for a 12 inch diameter rack tom. And trying to decide what depth I want. I have been wondering about drum depths and why they are in standard sizes.

I understand the need for standard drum diameters. So that standard sized drum heads can be manufactured and sold. But why are drums made in standard depths?

It seems that if a drum were designed for optimum tone, sound projection and tuning ability, the depth of the drums would not be in standard sizes.
I can imagine it would be difficult to market tom sizes such as 12 x 8.75 or 13 x 9.64, etc.. However, if it was discovered that the optimum depth for a 12 inch diameter maple shell at 7.5 mm thickness was 8.75 inches, then that could become the accepted normal depth.

So my question is why are drums, in particular rack toms, made in standard depths of 8, 9, 10, 11 and so on?
Has someone experimented to find out how different drum depths affect the sound and the ability to tune the drum?
And did they find that the optimum depths turned out to be exactly 8, 9, 10, 11 inches?


( Andy, please pick up the white courtesy phone! )



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KarlCrafton

Platinum Member
Did you do a "golden ratio" for you depth examples?

I ask because I played on a wood snare a few years ago that was made with the GR, and I was amazed at its sound.
Just a standard Keller shell, but the depth was the GR for a 14" diam.

Not sure why shells were originally 8x12, 9x13, etc..., then "standard" became 9x12, 10x13.
I've had all the depths for 12-14, and the traditional sizes sound, and react the best for me. The other sizes just seem to have too much "air" within the sound. Even 1" deeper than traditional aren't as pleasing.
I prefer shorter floor toms as well. A 13, or, 14x16 sounds better to me than a 16x16.
 

Red Menace

Platinum Member
You don't need a 12" rack tom Jim. You should buy my Tempus snare so that I can buy a Supraphonic.

Dooooo eeeeet...
 

Hollywood Jim

Platinum Member
Did you do a "golden ratio" for you depth examples?

I ask because I played on a wood snare a few years ago that was made with the GR, and I was amazed at its sound.
Just a standard Keller shell, but the depth was the GR for a 14" diam.

Not sure why shells were originally 8x12, 9x13, etc..., then "standard" became 9x12, 10x13.
I've had all the depths for 12-14, and the traditional sizes sound, and react the best for me. The other sizes just seem to have too much "air" within the sound. Even 1" deeper than traditional aren't as pleasing.
I prefer shorter floor toms as well. A 13, or, 14x16 sounds better to me than a 16x16.
I forgot, is the "golden ratio" 1.5?

A 1.5 ratio would give me an 8" depth for a 12" diameter drum. And an 8.67" depth for a 13" diameter drum.

Yeah, I think I have too much air to move with my existing toms. I currently have a 12" dia x 10" deep and a 13" dia x 11" deep.

I want to try something shallower, but I don't know what to expect with different depths.


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mmulcahy1

Platinum Member
I get what you're saying about the standard depths - or lack the of.

My toms are 10x8 & 12x9. My 12" tom is sweet with it's 9" depth. I couldn't imagine it being 7.5" or 8" like I see on other kits. To me, going up 2 inches in diameter and 1 inch in depth makes sense.... 8x7, 10x8, 12x9, 14x10.... This puts the 13" tom in a weird place, though.
 

porter

Platinum Member
I forgot, is the "golden ratio" 1.5?

A 1.5 ratio would give me an 8" depth for a 12" diameter drum. And an 8.67" depth for a 13" diameter drum.

Yeah, I think I have too much air to move with my existing toms. I currently have a 12" dia x 10" deep and a 13" dia x 11" deep.

I want to try something shallower, but I don't know what to expect with different depths.
Golden ratio in decimal is 1.618. Dividing the diameter by that would get our 'optimal depth'. So for our typical sizes, you'd get:

10" x 6.2"
12" x 7.4"
13" x 8"
14" x 8.7"
16" x 9.9"
22" x 13.6"

and so on. That's pretty short for a floor tom and this would intimate that Tama has the right idea with their "hyper-drive" 10" toms which are 6.5" deep. However... I think that if there is an "optimal depth" for any particular diameter of drum, it probably depends on thickness/material/etc. and isn't a universal constant for all drums of that diameter. I mean, common practice already totally botches the golden ratio for floor toms, and those sizes generally sound great!

It is interesting that the GR applied to a 22" kick gets us close to a 22x14" size, which I think most of us on this forum would take as divine justification for that great size ;)

I went for 10x7.5", 12x8", 15x14", and 20x15" on my custom kit. I definitely prefer the shallower rack toms for placement over the bass drum, but I doubt I'd really notice/care about the sound difference if the toms were 10x8 and 12x9 or whatever.
 

Notbob

Senior Member
There is one reason and one reason only why shells are certain depths. It's all controlled by the drum bag and case cartel. They've got a lock on it. They make certain sizes and everyone else has to conform. Youse don' wan yer drum to be shakin aroun in dere, amiright? Bad things could happen, eh? I mean, it'd be a shame if yer drums, I dunno, caught fire or sumpthin because of the friction of a too tight case. Am I making myself understood?

There is nothing that a good conspiracy theory can't solve.


In all honesty, I think drum depths came about this way:

Harry: "How deep should we make this shell?"
Barry: "How's about this deep?" (holds hands apart)
Harry: "What's that, about 10 inches?"
Barry: "More or less"
Harry: "OK, 10 inches sounds good to me"
Barry: "Yeah, that's what she said!"

After decades in the engineering field I get the impression that most standards started out as eyeball approximations which, if successful, were then measured and rounded off to the nearest convenient number.
 

Hollywood Jim

Platinum Member
Golden ratio in decimal is 1.618. Dividing the diameter by that would get our 'optimal depth'. So for our typical sizes, you'd get:
10" x 6.2" 12" x 7.4" 13" x 8" 14" x 8.7" 16" x 9.9" 22" x 13.6"

and so on. That's pretty short for a floor tom and this would intimate that Tama has the right idea with their "hyper-drive" 10" toms which are 6.5" deep. However... I think that if there is an "optimal depth" for any particular diameter of drum, it probably depends on thickness/material/etc. and isn't a universal constant for all drums of that diameter. I mean, common practice already totally botches the golden ratio for floor toms, and those sizes generally sound great!

It is interesting that the GR applied to a 22" kick gets us close to a 22x14" size, which I think most of us on this forum would take as divine justification for that great size ;)

I went for 10x7.5", 12x8", 15x14", and 20x15" on my custom kit. I definitely prefer the shallower rack toms for placement over the bass drum, but I doubt I'd really notice/care about the sound difference if the toms were 10x8 and 12x9 or whatever.
OK thanks !!

Good information.

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DrumEatDrum

Platinum Member
It's been said (although not 100% proven) Gene Krupa was at the Slingerland warehouse, he picked out a 9x13 tom, and a 16x16 floor tom out of the drums they had, and declared those to be the ultimate sizes, and it just sort of stuck.

But you could say there really are no standard sizes. Early drum kits used Chinese toms, with the 9x13 not making an appearance in the Ludwig catalog until the very late 30's. And even in the 1940's you can see 7x11 toms and 14x16 toms in catalogs. And in the 50's, Ludwig had a 12" depth bass drum available.
http://www.vintagedrumguide.com/ludwig_drumsets.html

Then in the 80's, everyone went power sizes, but different manufactures had different definitions of what a power depth was. "Traditional" depths were very rare on new kits for a good 10-15 years.

And then DW came out with the FAST sizes, which were neither traditional or power.

And now we're back to so-called traditional sizes.

It's been an evolution over time.
 

cornelius

Silver Member
...So my question is why are drums, in particular rack toms, made in standard depths of 8, 9, 10, 11 and so on?
Has someone experimented to find out how different drum depths affect the sound and the ability to tune the drum?
And did they find that the optimum depths turned out to be exactly 8, 9, 10, 11 inches?


( Andy, please pick up the white courtesy phone! )
I’m not sure exactly where “standard” depth sizes came from - something about the size of hat boxes back in the day, but not sure about that...

I will say though, that 8” depth for a 12” tom is the magic size. I also found it interesting that traditionally a 16” concert tom was 14x16 instead of 16x16...

Anyway, the only time that heard of someone actually doing the math, was John Good from DW. This was years ago, but I remember something about him noticing that two things happen with a drum shell - air moves from the top head to the bottom, and vibration travels down the shell. His approach was to make those occurrences happen in sync with each other (vibration moves faster than air) - hence his FAST tom sizes - which have become somewhat of a standard over recent years...
 
D

drumming sort of person

Guest
And did they find that the optimum depths turned out to be exactly 8, 9, 10, 11 inches?
Who is "they" and what is "optimum"? Everyone hears things a bit differently, so there is no optimum anything for anyone. You can get toms in a number of different depths. Get whatever floats your boat. Better yet, get some rototoms.
 

GruntersDad

Administrator - Mayor
Staff member
Suggesting that the sizes are dictated by the bag and case cartel is like my mom's (RIP) theory that planes are late to arrive so that people at airports will pay more for parking.

And then why does Sonor have so many 17.5 deep bass drums?
 

bobdadruma

Platinum Member
I did some experimenting with tom depth differences a few years ago.
I found very little audible difference in sound between an 8x12 and a 7x12 tom.
At least my ears couldn't detect it. I found the same to be true with 7x10 and 8x10 toms. 1 inch depth difference doesn't seem to be enough to make a big sound change in toms.
 

Tommy_D

Platinum Member
I think its about balancing the tonal and sonic qualities of the drum. A 12x7 may really sing in the middle to higher tunings, but doesnt have enough "oomph" to get a clear low tuning. They end up sounding muddy at low tunings. A 12x8 is probably pretty similar as 1" isnt going to change too much. However a 12x9 and 12x10 bring more grunt and lower tones to the drum. It probably brings more complexity to the sound as the higher tunings can have clear stick definition with bright attack but have darker undertones in its resonance. There is also a greater ability to get pitch bend in the slightly deeper drum. If you go too far in your depth and enter in to the "power tom" sizes you begin to lose your ability have clear higher tunings. They become pingy and lack resonance. Mid and low tunings work best with this depth drum.

So its all a matter of balancing what the drum can do. The 12x9 is probably a standard size because it can play just about everything. Its a "jack of all trades/master of none" sort of drum. Thats not to say its bad. Its actually pretty great for us drummers. You buy a kit with standard sizes and you are ready for just about anything.
 

keep it simple

Platinum Member
( Andy, please pick up the white courtesy phone! )
Sorry I'm late to the party Jim.

Ok, I'm going to be a bore, & start by restating something that purveys everything we do in drum design - Features / specifications (& that includes depths) in isolation are close to meaningless. Only features / specifications, when considered in context with every other aspect of the design, make a meaningful difference. For example, you could say that you can't really hear the differences in depths, in shell thickness, with or without a wrap, weight of hardware, hoop type, bearing edges, etc, etc, etc, & that may be true, but only within a certain context. Hearing the differences in all these elements depends on how those elements sit within an overall design.

The above absolutely applies to golden ratios, nodal points, & a whole raft of often sweepingly applied "rules". I've come to these conclusions through comparison trial style research - lots of it., & non more so than depth.

The relationship of depth - diameter is easy & well understood. More shallow = less overtones (both the ones you want, & the ones you don't), a cleaner fundamental. Deeper = more overtones (again, both the ones you want, & the ones you don't - but typically different ones), & consequently a diminished fundamental. That's all fine, but the final result can be augmented massively by other features / specifications.

Of course, "standard" depths are a product of fashion to some extent, but also what tends to work best across a range of standard constructions, standard tunings, & pleasing to the average drum company customer. Players tend to order drum sizes / depths based on their past experiences. If those past experiences have been within a standard range of constructional types, then standard thinking will apply, & the standard is perpetuated, often for good reason.
 

Hollywood Jim

Platinum Member
Thank you Andy, Bobdadruma, and Tomm_D.

That is really what I wanted to know.

I knew that diameter, bearing edge, shell thickness and shell material had a big influence on the sound of a drum.
I was trying to understand why some toms were difficult to tune. And I was trying to decide which size toms to buy.

It just seemed strange to me that drum designers somehow settled on even numbers of inches for depth; when they could be making drums at any depth they want.

And I knew that if Andy were selling a 12 inch diameter drum and the depth of say 9.570600003 inches made the drum sound and perform perfect, then he would be building them at that depth.


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keep it simple

Platinum Member
And I knew that if Andy were selling a 12 inch diameter drum and the depth of say 9.570600003 inches made the drum sound and perform perfect, then he would be building them at that depth.
We sometimes build to odd depths Jim, but it's never as a result of calculation. A standard depth for one series of snares we produce is 5.75". The reason behind it is simple. In that design, we think 5.75" delivers exactly what we want in terms of characteristics compared to the more standard 5" or 5.5". In the same series, we prefer 7" depth to the more standard 6.5". Same reasoning behind that decision too.
 

Hollywood Jim

Platinum Member
We sometimes build to odd depths Jim, but it's never as a result of calculation. A standard depth for one series of snares we produce is 5.75". The reason behind it is simple. In that design, we think 5.75" delivers exactly what we want in terms of characteristics compared to the more standard 5" or 5.5". In the same series, we prefer 7" depth to the more standard 6.5". Same reasoning behind that decision too.
Very good !

Thank you for the help.

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