AFMG Network Forum

M.Ermilio · Member

So we are switching over from our TEF20 into EASRA so we can make GLL data with this test system. (We already have other EASRA measurement systems setup already)

This system used TEF20 because it's a LARGE speaker outdoor measurement with the microphone 27' from the DUT. With the TEF20 that gave us a accuracy of +/- 1dB as long as our sweep times were longer than 10sec.

Right now my problem is that with only taking the TEF20 out and plugging in EASRA the results are all over the place. Above 600hz the consistency just starts to fall apart. With a swing as much as 10dB. This is with a 10.9 second sweep time with 1 average.

Adding in averaging makes the results even worse. This is with 6 averages per curve.

What is the difference between the two systems here? And why does averaging curves together cause huge drops in magnitude?

I'm not seeing a TDS signal when I go to run sweeps, is there no way to perform a TDS sweep without the EASRA Gateway? That's a pretty big problem since it's no longer in production. How am I supposed to use the TDS module? What is different about the Aubion equipment that my RME equipment cannot also do?

~Mike Ermilio

Waldemar · Member

Hi Mike,

it is surprising me also, that you measure such big uncertainty for high frequencies.
May be it is due to the large distance of 27' outdoors. Was the weather very windy?
The measurements should be done better in an anechoic room, of course.
The TDS algorithm in EASERA can be done with the AUBION interface only. The algorithm must rely on the full compensation of the electrical run time in the device.

M.Ermilio · Member

Waldemar, Yes an anechoic room would be nice but it was not windy that day. And while the room we do have is very accurate for smaller speakers the size of the horns and cabinets we're measuring does not work in that room.

I plugged in the Aubion X.8 following the manuals instructions. I will try taking measurement today with it and will report back my findings.