The Autotune System

The huge rims are held onto the drum with pairs of metal rollers (on the early drums, nylon blocks were used later). Inside the rims are metal runners, set at an angle. One of these runners has a toothed track set into it which engages in a gear wheel, set in the tuning block.

The early drums are fitted with sets of machined steel rollers. The rims have angled runners which engage in these.
Using the supplied ratchet on the single tuning lug drives this toothed gear.
One of the angled runners has a toothed rack which engages in the gear.

This gear is turned by a ratchet, which turns the whole rim. Consequently the head is either screwed on or off, just like a giant jam-jar lid. The big advantages are extremely fast tuning and head change and the ability to tune any head on any part of the kit whilst sitting at the drum stool (well - you might have to stretch a bit on a big kit!).

Here is a twelve inch Tom without rims or skins.
First we place the skin on the drum.
Next we place the thin fine tuning ring on top of the skin.
The chrome rim is now placed in position with the rack engaged in the toothed gear.
The ratchet is now used to tension the skin, about a quarter turn should do it.
It is now possible to adjust the tuning with one hand, whilst hitting the drum with the other. The whole sequence takes about 30 seconds.

This part of the system works quite well. There are just two slight problems:

One is that rotating of the rims can put a 'twist' in the skins, causing ripples at the edges. This is easily overcome by slightly over tensioning then backing off a little to allow the tension to even out. A dab of vaseline helps, too.

The other slight problem is that whilst the tuning range is very big, with old skins (ones that have stretched a bit too far) it is possible to run out of adjustment if you are after very high tunings. This doesn't happen on conventional lug tuned drums.

The Fine-tuning system.

Oh dear. This is the weak spot of the kit!

The Arbiter flats and Arbiter AT drums use a different principle and it is interesting to note that the fine-tuning idea has been abandoned. On a flats or AT kit you can increase or decrease the tension of the whole skin, but if a few heavy rim shots put a slack area on one side of the skin there is nothing you can do other than to put up with it or change the skin. Having said that, providing the skins are in good condition then the drums should tune nice and evenly, which is something that is very difficult for many of us to achieve on a conventional kit!

On the original Autotune kit the drums are provided with a fine tuning mechanism. This consists of a number of screws which pass through the rim.

The square headed screw passes through the chrome rim and presses into the thin metal ring underneath. This tensions the skin in that area.
The thin metal tuning ring bends under the influence of the screws to selectively tension parts of the skin.
Have a look under the drum riser next time you play a venue, see if you can find a few of these ;-) On later kits they were burred over on the end to stop them falling out.

Underneath the rim but above the skin is a thin metal ring, like a huge washer. When the screws are screwed in the ring is pushed down onto the skin and tensions that part of the skin. It is a little like the way a conventional drum is tuned in principle - but alas has several serious problems in practice!

First: The metal rings are rather thin. A conventional drum rim, being fairly thick and heavy, bends smoothly and gradually between the tensioning bolts. The thin rings tend to give a sharp indentation, putting a narrow ripple into the skin. If you are lucky, this is what you want, but more often, this misses the slack area you wish to tension so instead of tightening up a slack spot, you keep the slack area and put two sharp ripples either side of it.

Second: There aren't enough tension screws. The floor toms have six, the 12" tom has five, the 10" has four and the 8" has just three.

Third: The heads stay stationary on the shells and the rims rotate when you tune the drums with the ratchet. Imagine you have just spent ten minutes carefully tweaking the fine tuning screws to get the head nice and evenly tuned. You then tweak the whole rim up or down a bit with the ratchet... and all the carefully adjusted screws now line up with the wrong bit of head!

Fourth: The screws can be screwed in so far (whilst desperately trying to take up a slack area of an iffy skin) that they will actually bend the metal ring, so when you screw it out again, it stays tight at that spot until you remove the ring and straighten it out again with a hammer or with pliers!

Fifth: If the skin is nice and even and the fine tuning isn't required, the screws are slackened off. On the early drums there is nothing to keep them in place, so they rattle loose and fall out. That is why many Autotune kits these days will have at least some fine tuning screws missing (they are lying under drum risers and stage curtains in venues throughout the country!)

The one drum where the shortcomings of the fine tuning mechanism really spoils things is the snare drum. The tighter tension on the large diameter skin as well as the probablity of rim shots means you are more likely to encounter lack of even tension. Consequently the tuning system is much more likely to show its failings here than on the Toms. When I purchased my kit I did so without the snare drum, choosing a Slingerland Sound King instead. I think this was fairly standard practice.

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