TOPIC:

Hello,

The E.A.R.S. jig is indeed a great low-cost alternative to expensive counterparts such as the KEMAR or HATS with REW software. I've had fun measuring headphones and IEMs using this. However, what about measuring smart-glasses which have speakers located on the sides of the glass stem? I've made a 3D printed head model which is modified to fit within the space of the two metal plates (on which the silicone ear material rests). I am aware that jig may not be intended for use with smart-glasses and perhaps more suited to measurement of headphones and earphones.

Is it still possible to gather meaningful data for smart glasses? Due to their open-ear design and position a few centimeters away from the ear canal, the audio systems in these usually cannot generate sufficient SPL (84 dB with headphones, 94 dB with IEMs) at 300 Hz even at 0 dBFS of input. Whereas the SPL calibration procedure in the manual expects this condition to be satisfied.

Any tips or pointers in getting a reliable measurement? I am using the RAW compensation curves as I just want a reading of whatever reaches the microphone capsules. Do I need to change the gain switches in the device to 36 dB to make it more sensitive? If so, does the SPL calibration procedure remain the same? Is there also any justification to why 300 Hz is chosen, why 84 dB SPL is used for headphones but 94 dB SPL (equivalent to 1 Pascal) for IEMs?

Thanks!

Hello, 
If I understand correctly, you shouldn't do anything . You will indeed get an accurate measurement of what reaches the microphone and it will show a big low frequency rolloff.  To the extent that the dimensions of the E.A.R. are the same as a real ear,. that's how a person hears it.