AFMG Network Forum

mpincus · Member

Stefan:

Thanks for the information. I wasn't that interested in the trace file. So, I ran it with just the impact file, and it worked fine.

I do have another question - same project, but different topic. So, feel free to move this to a new string...

There are some studies that show how intelligibility decreases as SPL increases (over 85 dB, I think). Does Aura's STI algorithm take this into account, or does it simply compare direct sound to reverberent+background noise?

- Michael

Stefan · Member

Generally there are three ways to calculate the STI in EASE:

1) Standard Mapping, this utilizes a rather historic approach by deriving RaSTI from AlCons. The calculation of AlCons does consider the specified Noise levels.

2) AURA Mapping calculates the STI from the echograms as defined by IEC 60268-16.

3) EASE Probe / AURA Response calculates the STI from the impulse response as defined by IEC 60268-16.

However, none of these functions directly includes the two actual additions to the standard, which are taking into account octave-wise noise levels as well as signal masking.

You are right, the latest version of the IEC specifies how signal levels can be taken into account, too. This particularly reflects the effect of lower intelligibility if one octave band is very "loud" and thus masks the other bands.

The next major EASE Version will improve all of the above by unifying and extending the functionality already available.

Stefan

John Foulkes · Member

Stefan,

When you say that none of these functions take into account octave-wise noise levels, does that mean that the AI/PI calculations in Eyes do not consider the noise data entered as part of the Room Data?

And what about the Aura STI calculation? There's no "noise on" setting like in the standard Eyes calculation dialog, so it's not clear to me that the data is included in the calculation.

Note: I just put in the request to update to 4.2; these questions are based on 4.1.

Thanks!