Hi
Is there any way I could use REW to measure the Speech Transmission Index (STI) of a room?
STI measures speech intelligibility and is based on the Modulation Transfer Function (MTF) of a system (a room in this case). The idea of STI is to send a signal (usually a pink noise) which is filtered to have the spectrum of human speech. The signal consists of 7 octave bands from 125 to 8000 Hz. Each octave band is modulated by 14 one-third octave-wide frequency bands starting from 0.63 Hz to 16 Hz, resulting in 98 MTFs.
Thankfully, MTF for each octave band and modulation frequency can be derived from the impulse response using the following equation (ICE 60268-16):
mk (fm) = [|∫hk (t) e ^(-j2╥fmt) dt|]/ ∫ hk (t)^2 dt
Both integrals are from 0 to ∞.
where,
hk (t) is impulse response of octave band k;
fm is modulation frequency.
This is the theory, but I have no idea how to implement that. Your help is highly appreciated.
I know the equation looks messy, but I do not know how to type it here correctly. If possible, I can post a picture of the equation in the right format.
Thank you!
Is there any way I could use REW to measure the Speech Transmission Index (STI) of a room?
STI measures speech intelligibility and is based on the Modulation Transfer Function (MTF) of a system (a room in this case). The idea of STI is to send a signal (usually a pink noise) which is filtered to have the spectrum of human speech. The signal consists of 7 octave bands from 125 to 8000 Hz. Each octave band is modulated by 14 one-third octave-wide frequency bands starting from 0.63 Hz to 16 Hz, resulting in 98 MTFs.
Thankfully, MTF for each octave band and modulation frequency can be derived from the impulse response using the following equation (ICE 60268-16):
mk (fm) = [|∫hk (t) e ^(-j2╥fmt) dt|]/ ∫ hk (t)^2 dt
Both integrals are from 0 to ∞.
where,
hk (t) is impulse response of octave band k;
fm is modulation frequency.
This is the theory, but I have no idea how to implement that. Your help is highly appreciated.
I know the equation looks messy, but I do not know how to type it here correctly. If possible, I can post a picture of the equation in the right format.
Thank you!