Subject: [AUDITORY] low frequency noise in booth - UPDATE From: "Ferguson, Sarah Hargus" <safergus@xxxxxxxx> Date: Mon, 7 Jan 2008 16:23:10 -0600 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Many thanks to all of you who responded to my call for help in dealing with the 16-Hz noise I was encountering in my sound booth. I was surprised to see how many people have had similar problems, because it's something I've never run into before (though I guess I've only calibrated in a total of 6 booths over my career).=20 I tried several of the suggested solutions, including changing the orientation of my coupler and placing the coupler on a soft surface (neither of those helped). I checked the spectra of my speech and babble calibration signals and determined that C weighting would have no impact on them. Unfortunately, the noise level was still close to 70 dB C.=20 Finally, skimming Arlinger (1997) made me think to try my **2-cc** coupler - and that solved the problem. Measured in this coupler, the noise is 40 dB C or 50 dB SPL, low enough for me to measure my signals at my actual test levels.=20 All of this raises a larger question about calibration, which I'll pose in a new thread.=20 Cheers SARAH FERGUSON ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~=20 Sarah Hargus Ferguson, Ph.D., CCC-A Assistant Professor Department of Speech-Language-Hearing: Sciences and Disorders=20 University of Kansas=20 Dole Center 1000 Sunnyside Ave., Room 3001=20 Lawrence, KS 66045 office: (785)864-1116 Speech Acoustics and Perception Lab: (785)864-0610 http://www.ku.edu/~splh/Faculty/FergusonBio.html=20 =20