The Compressor tuning system
The compressor tuning frame is a funnel shaped, relatively high tuning rim, which influences the overtones and the overall frequencies of the bodhrán in a positive way.
The Compressor tuning frame
Drums fitted with the compressor rim show a more defined, clear and dry sound compared to a classical tuning system, therefore these drums can be heard better when mixed with other instruments without being loud or obtrusive. The clear sound makes the compressor tuned drums your best choice not only for studio work and in an amplified live environment, but also for acoustic sessions.
If you compare the structure of overtones to a classical bodhrán you will realize that the compressor frame provides a more regulated and a clearer structure. This means that the partial tones have a sharply bounded line and undefined overtone areas are often compressed to one defined overtone. Since all overtones are well structured it is easier to mix the drum either on stage or studio. The bass is also less boomy/roaring and better controlled.
Another advantage, apart from the positive influence of the sound, is more playing comfort. The funnel tuning rim gives the skin hand a nice rest. As no screws are touched, you get a comfortable and ergonomic place for your skin hand. Along with this, the tuning screws have changed from single tuning blocks to a solid wooden frame going all the way around the drum. This provides a solid fixation along with a more professional look.
Martin O'Neill hat den Kompressorstimmrahmen getestet, ohne zu wissen, was die Intention des Tests war:
"I've been playing the drum loads and my overall impression is that mic'ed up the bottom end seems more controllable (i.e. Not so boomy), fairly even across the range…
One difference not sound related that I do prefer is the funnel shape of the tuning rim makes it more comfortable to play. Small thing, but does make a difference."
Details of the studio tests
If you compare the overtone structure of a classical bodhrán with that of a compressor drum, you will notice that the compressor drum has a clearer, more ordered frequency structure. This means that the partial tones have a sharply bounded line and undefined overtone areas are often compressed to one defined overtone.
Two pictures (top and center right) show the frequency analysis of a new RWE with a new skin (not played in). The first picture shows the results of the classic tuning system, the second shows the result of the new compressor tuning system.
The curves represent the presence of the frequencies in the full tonal spectrum. The peaks are representing the partial tones, meaning the basic tone and the overtones. A defined tone has sharp and marked off peaks, whereas a noise has less to no peaks.
Compare the pictures of the drum analysis, with the picture of the structure of overtones of a guitar (bottom) to see how big the influence of the new rim can be.
These pictures show analysis taken from free vibrating drums.