Princeton University  




The 3D3A Lab consists of three adjacent sections:

1. The Anechoic Chamber

2. The Listening Room

3. The Control Room


1. The Anechoic Chamber


The 3D3A Lab is equipped with a highly reconfigurable anechoic chamber that was built in-house and that has adjustable/removable walls which can be moved on casters. It measures w: 3.0 m, l: 3.5 m and h: 2.2 m. The walls, floor and cieling are covered with 1 foot x 1 foot melamine square wedges. The wedges are 8 inches deep and give the chamber a cutoff frequency of 425 Hz. The chamber is lit with strings of green diode lights that give it a pleasant ambiance. The lighting and the fact that the chamber is not soundproof, make it a pleasant environment for human test subjects.

Two dummy head microphones are availble for measurements in the anechoic chamber and the listening room. The first is a Neumann Ku100 dummy head (called Fritz):

and the second is a B&K 4100-D (called Lars):


2. The Listening Room:


The 3D3A Lab's Listening Room was designed to be similar to a typical home or studio environment. The level of sound reflection can be conrolled by repositioning fiberglass panels (RFZ panels by RealTraps). There is a wide choice of loudspeakers ranging from passive concentric to active loudspeakers and 2 Hsu Research ULS-15 subwoofers. A survey of the directivity of loudspeakers in use at the 3D3A Lab, can be found here.


3. The Control Room:


The control room is equiped with state-of-the-art audio equipment, computers, processors and acoustical diagnostics tools. The equipment includes:

1 B&K Microphone Type 4189 scientific microphone
1 B&K 2693-A-OS4 Two-channel DeltaTron conditioning amplifier
1 B&K 4231 microphone calibrator
2 DPA 4060-BM miniature microphones (for in-ear binaural measurements/recording)
1 Neumann Ku100 dummy head microphone
1 B&K 4100-D (HATS) dummy head microphone
1 EmmLabs Switchman Control Center
2 Lynx Aurora 8 8-channel AD/DA converters with 2 Lynx AES16e PCI Express cards
2 Millenia HV-3D 8-channel microphone preamps
2 Bryston 6B SST Pro 3-channel (150 W/channel) amplifiers
1 Bryston 2B-LP Pro 2-channel amplifier.
1 Coleman Audio M3PH Controller/Switcher and passive volume control
1 HR-UDC1 Universal Digital Audio Converter by Radio Design Labs
1 Furman IT-20 II Balanced Power Conditionner
1 Furman PL-Pro DMC Power Conditionner
2 Nicolet and HP oscilloscopes
3 Apple Macintosh computers with > 2 TB storage (HD and solid state).
Various laser aligning and leveling tools
Various custom-made loudspeaker and microphone stands with multiple degrees of freedom
Various sound absorption panels, foam, wedges, and room treatment material.
Audio and Acoustical Analysis Software: Plogue Bidule, SIR2 Convolver, FuzzMeasure Pro, SpectraFoo CompleteX.
Various specialized acoustical analysis software developed in-house using Mathematica.