Aalto Acoustics Lab Facilities
They include three anechoic chambers (built in 1970; renovated in 2019), a variable acoustics room (built in 2019), a listening test room which meets the standards of subjective audio testing (built in 1999), three independent sound-insulated booths for headphone listening tests (built in 2011), standard acoustic measurement equipment and systems, such as measurement microphones and amplifiers, accelerometers, signal analyzers, sound level meters, an acoustic impedance measurement system, a laser Doppler vibrometer, and a dummy head. Additionally, the Aalto Acoustics Lab provides excellent audio reproduction systems for research and demonstrations, including reference-quality headphones and many Genelec loudspeakers.
The anechoic chambers and the acoustic measurement laboratory were renovated in 2017-2019 and were reopened for use in December 2019. The new wedges are shorter than the previous ones, making the chambers more spacious than before. The wedges absorb mainly high frequencies whereas the low frequencies are absorbed using damped metallic plates behind the wedges. This modern design is both more efficient than traditional techniques in terms of the use of space and absorption at low frequencies.
Furthermore, the sound insulation of the measurement spaces was improved. The background noise level in the anechoic chambers is now less than 0 dB.
After the renovation in 2019, the various special rooms were named after Finnish pioneers in acoustics and audio technology. The large anechoic chamber is called Lampio (after Dr. Eero Lampio, who designed the room in the 1960s), the multichannel chamber is called Wilska (after Dr. Alvar Wilska), the small anechoic chamber is called Köykkä (after Tapio M. Köykkä), the listening room is called Otala (after Prof. Matti Otala), and the variable acoustics room is called Arni (after Paavo Arni). The original absorption wedges in Lampio were replaced in 2005 and they were replaced again in 2019. Arni was an acoustic reverberation chamber in the 1970s and 1980s.
The seminar room of the Aalto Acoustics Lab is called Karjalainen, and the meeting room is called Martikainen. These names remind us of the first professor of acoustics, Matti Karjalainen, and of Ilpo Martikainen, who studied acoustics in Otaniemi, founded a loudspeaker company in Iisalmi, and was named an Honorary Doctor of Helsinki University of Technology.