Extremely low Reverberation Time Readings

[12083900]

Hi, 

Im new to the software and Im trying to calculate some simple reverberation times, Ive imported dxf geometry and the reverberation times are just incredibly low. I followed a couple of tutorials and had the same problem with the tutorial file compared to the results shown in the walk through.

The first one here was fine:

http://wiki.naturalfrequency.com/wiki/Ecotect_RT_Graph 

But the second one here has the same problem as when I import my own geometry, the times are always very low.

http://wiki.naturalfrequency.com/archive/ecotect/tutorials/acoustics-reverb.htm

Im not sure if it was related but I also had a problem with the materials library saying it couldnt find "Ecotect.lib" I have since worked out to go to user preferences and set the path for this but the only .lib i got was either default or ecotect_v4.lib so I assumed the latter was correct. 

It just seems that whatever I do I get very low RT even if i increase the volume and make the materials all none absorptive.

Ive attached some pictures showing the discrepency between the tutorial results and mine, and also my geometry and the results I get if I say all the material is "Timber Clad Masonary" 

Any help would be very much appreciated thanks.

[Pennetier1]

Hi 12083900, 

Well it looks like nothing is wrong on your hand...

I have ran both tutorials and indeed, I got the same results than you did - note that there is an error though in that the Reverberation Time.eco has its ceiling set as Suspended Absorber when at the begining of the tutorial, it should be Plywood.

Because that first tutorial was quite old, I have ran the same file using Ecotect 5.2 (2003) - sure enough the results are similar than those they posted on the tutorial.

Although there is a large discrepency, I would have to go with the results of the latest version, unless you are certain that these number are indeed much too low.  Unfortunately, I am not verse enough in acoustics to determine first hand if these number are in the ball park or not.

I hope it does clarify things a bit for you, if not create more questions...

Cheers,

[Pennetier1]

12083900, 

I have actually found the culprit and unfortunately, it appears that the newest version is in the wrong.

Where the software should calculate 370 m2 of surface area (necessary for sabine calculation), the newest version shows 2,647 m2...

I am trying to see what causes this error; I do not think it is a unit issue.

Cheers,

[Pennetier1]

Hi 12083900,

I have found the issue, and it is actually simple to solve!

The speaker being on the same zone as the main space to be analyzed is what is throwing off that high surface area number.

Solution: move the speaker on its own non-thermal zone, and it should fix the issue.

Let me know if you have more questions on this topic, otherwise please accept as a solution so that others can benefit from this information.

Cheers,