Typically these devices are expensive, not so if you are willing to build your own. ETF provides a virtual slide show that explains the basics on small room acoustics and how ETF can be used to measure and interpret small room acoustics. Features of ETF High resolution measurement of low frequency resonances ETF provides two three-dimensional graphic displays that can be rotated by 90 degrees or examined with a top view option. This is ideal for loudspeaker quality assessment as well as fine tuning with an electronic equalizer. Adjustable gating provides the capability of performing high resolution pseudo anechoic measurements of loudspeakers.
Reverberation time is a measurement of the acoustic liveliness of a room.
ETF can be used to check listening rooms and studios for reverberation time. Absorption can be added or removed if required. Many tools designed for this purpose can give erroneous results with no hint that the result is erroneous. Do not under estimate this tool because of its low cost. Compare it with anything currently available.