“Furthermore, Herb’s quote above regarding 70-80 degree orientation was speaking specifically of DRC, STC or RT60 measurements. He actually says that in the quote linked to HT Shack.”

Correct – the section of the article you are referring to is clearly titled “In-room measurements.”

John

Furthermore, Herb’s quote above regarding 70-80 degree orientation was speaking specifically of DRC, STC or RT60 measurements. He actually says that in the quote linked to HT Shack.

Frequency response measurements are a different story. Again referring to the HT Shack link from which Herb’s quote was taken, he says this in the sentence before it: “… If you’re trying to measure the freq response of a particular source [e.g. a speaker], measure with the mic pointed at the source (which will minimize the effect of the mic body)…”

For the record, Herb has never advocated pointing the mic at the floor for any kind of measurements. Here is the mic orientation he recommends for various types of measurements (http://www.hometheatershack.com/forums/spl-meters-mics-calibration-sound-cards/15951-cross-spectrum-microphone-calibration-service-usa-26.html#post609630). John Mulcahy, creator of REW, also recommends the same thing (http://www.hometheatershack.com/forums/rew-forum/62260-calibration-error.html#post554918).

I would guess that the drop in response above 30kHz (in Figure 4) of the Dayton mic is a result of the microphone’s size. There was some recent videos made on microphone 101 on the eevblog that I found interesting – http://www.eevblog.com/2014/04/12/eevblog-602-introduction-to-microphones/

Chris

Thanks again. -Andi

Also, I’d check the max SPL specs of the mics you have, the Dayton is specified at (only) 127 dB, a quick look at the Aco Pacific site shows some of their mics have a spec up to 175 dB.