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Metloef Bodhrans - 'Gemini'

Custom built for Paul Marshall

Drum Technical Explanation (kind of)

Genus - 'Pelo'... Species- 'Pelohran'

This is a unique drum, built over a period of months by Rob Forkner of Metloef and designed in conjunction with myself, Paul Marshall, officially a drum nerd.

This page is only about the drum's design, construction and the theories at work. There is no assessment of sound quality. For that you need to see the Review page which is not yet written

The Genus

'Pelo' is a term of my own definition, it comes originally I believe from a Romany word meaning brother or friend (although I cannot trace references to it) and came to me via my good friend Niko Thomas with whom I built the pelodaiko. A 'Pelodrum' refers to any drum that is playable by two players where both heads are independently tunable. The connotations of 'pel' as a common prefix used for 'skin' are recognised. The finish which simulates a pint of stout is not an accident.

The name 'Gemini'

It's a fairly obvious choice of name but the symbolism is too strong to resist. It is not Siamese because the drums can readily be separated. Rob has already built a 'Siamese twin' drum called Dolly

"In classical Greece the twin stars of 'Gemini' were named Castor and Pollux, legendary twin sons of Zeus and brothers of Helen of Troy. They were among Jason's crew of argonauts in quest of the Golden Fleece. Romans called the stars the "Twin Brethren" and associated them with the principle of brotherhood considered to lie at the foundation of their empire. In Egypt they became Horus the Elder and Horus the Younger. In Babylon they were the "Great Twins," and they were viewed as twins in Arabia as well. In China they were Yin and Yang, representing eternal dualism, the two halves of a circle, and contrasting principles of existence." Paraphrased from the Clark Foundation

Although I'm not someone who gives much credence to astrology apart from the occasional rubbernecking glance over someone's shoulder at the newspaper, I find the symbolism to be supportive. It is ironic that my own star sign is Gemini and that the drum arrived with me on my 40th Birthday, it shares my date of birth and in many ways I and the Gemini drum offer another pairing because of this. Gemini is an 'air' sign, air is a significant factor in this drum.

So, what makes this drum different?

You mean apart from the fact that it's the world's first 2.5ft deep two headed bodhran? :) LOL

A drum's total sound comes from three sources, the membrane vibration, the resonance of the enclosed air and the resonance imparted by the shell. A traditional bodhran design is a frame drum where the depth of the shell is less than half the width of the head membrane. In such a drum there is no air resonance effect in the sound and there is minimal shell resonance although damping the shell does inhibit the skin's free movement. It is not surprising that the skin is THE most important element of a conventional bodhran's sound. It is also widely held that the shell really only plays a structural role.

The distinctive sound of this drum that makes it different from any other bodhran comes from the synergy brought about by bringing the twins together to create a chamber of enclosed air. In effect this traps vibrations within the drum and they in turn trigger both shell and air resonance where the drum is free to vibrate in such a manner. Because of the manner of holding and playing a bodhran, shell resonance is seriously impaired and can largely be ignored. An independent suspension system (ISS) and very careful arm/hand positioning, i.e. where the shell is not in contact with anything, would be required to bring out shell resonance. Although do-able theoretically there would be many issues compromising the player's ability to support and freely interact with the drum and it is unlikely that such practical issues could readily be overcome and permit efficient playing.

The second head on the drum is of vital importance. It mirrors the resonant head on a drumset rack tom. Through proper tuning and control, this head will control overall sustain, envelope (pitch bend), and in the case of the pelohran, the drone tone of the drum. Rob and I had both been experimenting with this and other elements of the construction independently before coming together to build this drum, It was very cool to find a like-minded builder.

With two players playing, the drum sacrifices the drone and envelope considerations but then again, the fact that two players are playing the same drum brings its own sound characteristics and visual elements. With two players, the sustain coming from the reso head is gone and the effect of the air chamber is additionally negated by having double the absorbent flesh inside, yet it still retains much of the 'bigness' of timbre. In my mind this is a good thing because it helps deliver clarity allowing stroke discrimination between the two players.

This design technically makes the drum a cylindrical drum, belying its framedrum roots, I prefer to consider it a hybrid. In fact even as two separate instruments, both are cylindrical drums given Rob's 14" head x 12" shell dimensions. However with that said, the drum is clearly a bodhran in spirit.

The skins still remain the most critical aspect to the sound of the drum however resonance, instead of being only a percent or two of the sound, becomes a much more significant and unique element of the drum's overall rich tonal character.

This is a new bodhran sound.

The skins

Rob and I discussed much to do with the skins for the drum, skin type, thicknesses, processing, appliques etc etc. On the drum there are two types of skins used, Kangaroo and Lambeg. If the drum were to be headed with double Roo or double Lambeg, I suspect the sound may be different as each has a subtle timbral difference from the other.

Because I am from N Ireland, I have access to Lambeggers, those who make the Lambeg drum. Anyone familiar with contemporary bodhran making will know that a goatskin prepared for the lambeg drum is ideal for the new flexi-style bodhrans, those with an easier 'action' and multi-octave capability. I was able to put Rob in touch with a source who also supplies Seamus O'Kane's & Paul McAuley's Lambeg skins and as a result he now has a small supply (they are hard to get). One of his first tries at using the Lambeg skins was this gemini drum.

Rob has been using Roo skins for several years in his Metloef drums and knows the skins and the processing inside out. The skins really are pushed hard to achieve the qualities that are desirable and this effort is borne out in skins with incredible flex despite their slightly thicker nature (on this drum, 0.5-0.7mm).

The Lambeg skin on the Gemini drum was not fully processed in this way and although thinner (about 0.4 - 0.5 mm), it does not yet have the same physical flex qualities as the roo. It will take this side of the drum a few months to be played in (if I can make my mind up which side to play :). Since dispatching the Gemini drum Rob has more fully processed some of the Lambeg skins and I understand that the results are more than favourable.

Appliques more...

Each skin bears a weighted patch. Again it is co-incident that Rob and I both had independently been using weighted skins, both looking to the Indian Tabla for inspiration. In my own low-tech solution, I have been using lumps of Blu-tack, putty used for fixing posters to walls etc. Rob has gone much more hi-tech using neoprene. Even the Blu-tack does not interfere with the playing at all and infact has led me to develop further some playing techniques that are new to me.

The patch has a clearly positive effect on both the attack and the tone of the drum. It most definitely affects the manner in which the drum head vibrates, this is most clearly heard in its more focused sound which accents the fundamental tone as well as reducing incidence of wolf tones. A weighted drum IMO is more forgiving in its tuning although I do admit to being a stickler for very small tuning ball-parks.

Striking on the patched area of the skin gives three distinct regions of attack, there is an inverse relationship between attack and fullness of tone. Striking outside the ptched area gives a soft attack with a full warm tone, striking on the outer clear ring gives more attack with some tone and striking directly on the patch gives greatest attack but at the cost of tone. Striking any drum at its centre node will always provide a greater attack with least full tone and least overtones, this attack characteristic is emphasised by the patch.

Each drum also bears the now commonly seen 'ring of black tape' that helps to dampen further any undesirable tones. In the case of Gemini there is a single round of 1.5" tape.

Tuning Mechanism

Rob has used the standard Metloef tuning mechanism on both these drums. A common sense use of thumb screws means that finally I have a drum that does not require me to carry around some sort of tool, be it an allen key or a screwdriver. My Swiss Army knife is often pressed into service. I urge all drum makers who make tunable bodhrans to adopt these. Where there is little tone difference between drums, use of these screws will be sufficient to make a Metloef my primary bodhran

The screws go through a hand tapped brass block and impact upon a small flat brass strip that sits on what appears to be an acrylic inner ring. It's functional and it's very effective. The thumbscrews are a godsend and one can tune whilst playing without the distraction of locating a tool, the bolt, and bringing both together.


Overall, I'm absolutely delighted with the drum. I think that's clear.

Because it is a first, in many ways a prototype, it will take a little time to get to know it and its sound but it is clearly destinctive in terms of sound and appearance. There is much about the drum that is experimental, I'm sure that not everything will perform as theorised and the drawing board will be revisited for minor modifications.

All things considered, the broad thrust of the drum's design is a complete success, Rob did a super job of working with the weird ideas & theories in practical terms. We can't claim to know scientifically to the nth degree why every little element works, but they do, and we have a semantic understanding of the processes and acoustics. The drum is a clear hybrid both in terms of the instrument and the two minds that created it. There is more and better to come.

Huge thanks go to Rob.