Room and Organ Acoustic Measurements of St. Jakobus Church Ilmenau - Part 1: Omnidirectional Room Impulse Responses

This is part of a dataset of organ recordings and room acoustic measurements of St. Jakobus Church, Ilmenau. For an overview of the complete dataset, please refer to Room and Organ Acoustic Measurements of St. Jakobus Church Ilmenau.

This dataset is an assemblage of omnidirectional Room Impulse Responses (RIRs) for multiple source receiver combinations in the church.  The file ROAM-JIL-Omnidirectional.sofa containes all the data like the RIRs themselfs, source and receiver positions, and other metadata. The data is provided as SOFA (v. 2.1) with convention SingleRoomSRIR 1.1 in accordance with AES69-2022.

Nine Earthworks M30 omnidirectional micropphones were used as receivers and distributed around the church. Microphones 1 - 6 where placed very close to the organ pipes to minimize the influence of the room in the recordings. To compare the immissions for the organist and the audience, microphone 7 was placed in front of the key desk and microphone 9 on the ground floor between the pews. Microphone 8 was suspended from the upper gallery in the middle of the nave, a position commonly used for organ concert recordings. 
Note that the positions of the microphones inside the organ are approximate, as it was not possible to take a direct bearing to the zero reference point.

A subwoofer and two loudspeakers were positioned as close as possible at the mouths of the facade pipes without risking damage to the organ.  To mimic the pipes radiation pattern, directional studio monitors (Genelec 7360A and 8341A ) where chosen.  On the opposite side of the church, in front of the altar, an omnidirectional source (Outline GSR Speaker and Subwoofer) was placed in order to have a significantly different place of excitation and to be able to perform room acoustic analyses in the classical sense.

Exponetial Sine Sweeps with a length of 15 s and 4 s of decay time were used as excitation signal. For the Genelec Subwoofer, the signal ranged from 18 Hz - 1 kHz, for all other loudspeakers from 20 Hz - 22 kHz. The Genelec 8341A speakers were calibrated to 90 dB SPL at a distance of 1 meter at 1 kHz. For the Outline GSR speaker with subwoofer and the Genelec 7360A, a similar level of approximately 90 dB SPL at a distance of 1 meter can be assumed.