“I’ve never heard my harp recorded like this before. This is exactly the way it sounds when I’m playing!” - Gayle Levant
1.1 - Overview
Since its birth in the early 1920’s by Dr Walter H. Schottky and Dr Erwin Gerlach, the ribbon microphone has withstood the test of time by becoming one of the industries most sort after type of microphone for recording various instruments and vocals within a recording studio. With memorable works such as Nuemann’s U87 Ribbon Microphone, Royer Labs R-series ribbon microphones, each manufacturer has adapted and almost perfected the infrastructure of the ribbon microphone. From the early experimenting with the components, such as how the ribbon is corrugated to how it is suspended and how much it is suspended by, to the use of magnets either side of the ribbon, to how thick the ribbon should be for the best in quality and what basic physics has taught us over time is the thinner the ribbon for better transient response and the response in any high end frequencies.
1.2 - Context
As a transducer, microphones are a unique transducer that convert the acoustic energy of a sound, or the sound pressure, that have been with us since the 1870’s, back when telephone engineers required the need to transform the human voice into electric currents to be sent down a wire to a recipient, which is then converted back into a sound that is heard through another transducer, the loud speaker or in telecommunications, the receiver. Ribbon microphones fall into the family of Dynamic Microphones. The other in this family being known as a moving coil microphone. Julian David, a German Audio Engineering associate theorizes that a ribbon microphone is “mechanically low tuned”, a ribbon microphones resonant frequencies rest in the low end. In an ideal world, any assistance from the ribbon is quite high and the dampening of the ribbon is especially low. Julian David also states that above the resonance, the impedance of a ribbon microphone is controlled by two key components: the ribbons mass and the mass load of air. (Julian David 2010) In his ribbon motor analysis, I have taken several points into account for my own research and analysis of my own microphones, these points will be examined and discussed in chapter 3.1 - Research.
1.3 - Summary of Aims and Objectives
Below is a list of aims and objectives I will have completed by the end of this final project.
To build two fully functioning ribbon microphones.
To identify how different ribbons affect the outcome of an audio recording.
To compare the outcome of each recorded signal and discuss the results.
To compare each ribbon, analysing the pros and cons of each one.
To research past experiments and adapt my own accordingly to have the best outcome and success.
To have two operational microphones.
To have a number of recordings from each microphone.
To understand how all components coincide and work together for a microphone to operate fully.
To acquire further knowledge of the ribbon microphone.
While pointed above, on a whole the primary objective of this investigation is to identify and compare the difference in frequencies and in the frequency response in a final recording of two ribbon microphones, each with different ribbons inside. One microphone will host a ribbon that is 1.2 microns thin and the second with host a ribbon that is 4.0 microns thin.
2. Literature Review
2.1 - Overview
The significance of this research is to gain crucial knowledge in the design and building of a ribbon microphone. Throughout this process, the insight that previous developers and builders of ribbon microphones, both past and present has been an intrical part of the stages of the research, design and the building process of both my microphones.
“A ribbon microphone solves a number of specific problems in the studio” - Gino Robair (June 2011)
While being an almost quick fix solution in the studio, ribbon microphones hold a purpose, like other types of microphone, to catch a sound as naturally and as true to the source as possible. However, unlike other types, a ribbon microphone is known as a velocity microphone, meaning that with the use of a thin aluminium foil that is electrically conductive placed between two magnets (or poles) to produce voltage by an electromagnetic induction.
2.2 - The Microphone Book (2ND Edition), John Eargle, 2004
The components that go into making a ribbon microphone cannot be overlooked. This area alone is the most important when moving forward in designing and building any microphone. Through this, Eargle’s The Microphone Book comes into play in this project by hosting an array of information and tips on the corrugation of the ribbon and the density of the ribbon itself. With this investigation being focused on the ribbon themselves, the difference in the outcome of the recording is not covered in this book and where this investigation picks up on that and will help in filling that gap. This book also hosts informative diagrams that will aid this process in the physical application process. Eargle explains response curves of ribbon microphones stating that the design of a ribbon microphone produces a “predictable” uniform pattern. With the use of high powered or high energy magnets, with this information along with the “improvement of base sensitivity” will lead to interesting results. Eargle’s point about the higher energy magnets with “new magnetic circuit materials” which allow for sensitivity improvements in the base which also allows a better beneficial switches which include the use of a shorter ribbon with better polar pattern behaviour and better high frequency response and performance.
3. Design & Build
3.1 - Research
The research part used through this process, within the literature review for background information and information on the importance of each and every part of a ribbon microphone. However, through this, information that was sourced was predominantly from as far back as the 1950’s, this was somewhat useful and adaptable to my own research.
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