SP395 SoundPro Audio Integrator
Form7492
Operation Manual
31
ACOUSTICS
This main menu selection includes the SP395’s Acoustical Analysis functions. These functions
are typically used to analyze sound or acoustic parameters in a room or space. These functions
typically use a microphone for input. The standard input source is the left input unless otherwise
noted. Also, phantom power is normally used to power the microphone.
The SP395 Acoustic Tests Include:
Real Time Analyzer (RTA)
FFT Analyzer
Energy Time Graph
Reverb Decay Time
Multi-Band Decay
The Acoustics Tests menu.
Real-Time Analyzer
The Real Time Analyzer or RTA is essentially an audio spectrum analyzer which graphs the dB
level of each audio octave or 1/3 octave band. Each band is graphed as a vertical bar, with the
height representing the SPL level of the individual octave or sub-octave bands within the audio
spectrum. The graph displays either a 15 dB or a 30 dB range. The display is updated
approximately twice per second, with selectable signal averaging times from 1 to 60 seconds.
The filter-based RTA responds much more quickly to changing sound levels than does the FFT
Analyzer function (below). The RTA function has frequency resolution to 1/3 octave. You can
use the fast-responding RTA function to analyze the frequency response and levels of live voice
and music. The 1/3 octave resolution is particularly useful, as this closely duplicates the
resolution of the human auditory system.
The RTA function includes an ANSI X curve weighting network for motion picture theater setup
is included. The SP395 RTA function uses ANSI Class 1 filters to separate the spectrum of the
audio signal at the microphone or left line input into octave band or 1/3 octave band segments.
RTA graphs can be stored to memory or compared with the “difference” mode for before and
after analysis.
The internal signal generator can be used to provide a pink noise test signal while using the RTA
function. RTA graphs can be stored and recalled for viewing and analyzing at a later time, and
the data can also be downloaded to a PC, or can be viewed in real time with the TerraLink
software.
