Meeting Topic: Microphones
Moderator Name: Per Sjösten
Speaker Name: Håkan Lindberg, AES Life Member & Jörg Pohl, Neumann Microphones
Meeting Location: Göteborg
In order to reach out to the membership and make the society more accessible to those in other parts of the country, the latest section meeting was held in Gothenburg. We are delighted to report that the event was success with a healthy attendance of members and guests.
We were very fortunate to have been allowed to use Svenska Gramafon Studio as the venue for the presentations. Kalle Gustafsson Jerneholm gave visitors an open invitation to wander around the studios during a break in recording sessions with 'The Sounds'. The myriad of studios and performance rooms is filled with a cornucopia of eclectic recording equipment all of which is in working order and maintained by the in house technicians. Everything from analogue tape and mixing desks to tape echoes and spring reverbs adorns every available space. An impressive array of backline is also available ranging from Moogs sysnthesisers to sitars.
The first presentation was given by veteran microphone historian and AES Life Member, Håkan Lindberg. Starting in the 1900's, Håkan talked us through the development of microphones for recording from the earliest experiments with direct optical recording to the creation of ribbon transducers to the most modern large diaphragm devices. One of the most interesting aspects of his presentation were the archived orchestral and vocal recordings which clearly demonstrated that microphone and recording technology has been of the highest quality for several decades prior to the digital revolution.
After the break, Jörg Pohl from Neumann Microphones in Germany, presented us with the latest developments in digital (or more correctly, digitised) microphones. Locating the analogue to digital converters as close to the microphone capsule as possible provides a basis for noiseless transfer of audio. One of the major obstacles to overcome is the dynamic range of the converter. The best ADC devices currently have a dynamic range of 115dB whereas the best condensor capsules can achieve dynamic ranges of 140dB or better. Neumann take a novel approach of splitting the large dynamic range of the analogue capsule over 2 discrete ADCs which are then summed to an AES3 output. Another advantage of digitisation is the ability to communicate remotely with the microphone to change polar pattern, switch filters on and off and more besides. Bit 29 of the AES3 stream is used for this purpose and is described in AES42-2010.
The evening ended with Q&A, one of the points being the perceptibility of latency in digital microphones. The concensus was that because the delay is no more than the time of flight from the typical monitor loudspeaker latency would not normally be an issue.
Written By: Steven Liddle