AFMG Network Forum

ChrisH · Member

Interesting to note on the AFMG newsletter that the IEC 60268-16 speech spectrum is being incorporated into the GLL viewer. I always apply the speech spectrum to any loudspeaker input signal when making STI predictions for PA/VA systems.
However, many consultants and audio engineers do not, insisting that the STI, or STIPA calculation takes care of the speech spectrum. To me this means that not only is their total SPL prediction wrong, but also the octave band SNR and hence the STI/STIPA are wrong too.
Can AFMG confirm for the record that applying the speech spectrum at the input stage is essential for STI predictions?

daniel · Member

"I always apply the speech spectrum to any loudspeaker input signal when making STI predictions..."
That's what I do. And also consider the crest factor: sine = 3dB, speech approx. 12dB! Otherwise the total SPL calculation is not correct.

coliseum8299 · Member

Hi ChrisH, at what stage are you applying the speech spectrum? I can only see the choice of either Pink Noise or Multitone in the "settings" tab under Room Data (EASE 4.4).

Is what you're saying that many users do, is use the Pink Noise setting in the Room Edit mode, then view the STI figure the Eyes module, but this is really wrong since the input signal isn't STIPA in the first place?

There seems to be another way to do this with STIPA as the input signal in the first instance in the Room Edit module, is that correct?

AFMG Silke Bögelein · Member

In EASE 4, the male speech spectrum should be added as a loudspeaker filter to receive standard conform STI simulations. Settings in the Calculations Results Window are post processing settings for the STI.
However, in our new product EASE 5-FE, among others, the Speech Spectrum is now an optional input signal.

coliseum8299 · Member

Hello Silke, thank you for your response,

Can you describe a click by click process to apply the male speech spectrum as a loudspeaker filter in EASE 4.4 in order to obtain accurate STI results please?

ChrisH · Member

Hi Coliseum - if using EASE v4 you can manually input the IEC 60268-16 male speech spectrum in the speaker SPL settings for each octave band. If you want you can save the EQ ('save file'), then load the file next time.