Re: 4Pi measurements [message #74246 is a reply to message #74245] |
Wed, 24 October 2012 15:11 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to previous message](/forum/theme/AudioRoundTable/images/down.png) |
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Wayne Parham
Messages: 18757 Registered: January 2001
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Illuminati (33rd Degree) |
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I agree with you - I wouldn't worry about your calibration. I think that's most important when you need a solid reference, like if you were planning to publish your charts or make some sort of formal comparisons. But for what you're doing, I am already comfortable with what you have. In a way, your four π speakers can be used as a reference, because they look just like what I would expect except for an additional first-order LP filter function above 2kHz. You can mentally conjugate that curve and feel comfortable with it.
On the low-end, that's not uncommon either. At very low frequencies, a Delta-Sigma converter has a hard time, it's just the nature of the process. That's why some measurements systems take forever when measuring low frequencies. They're trying to compensate for that. An old Nyquist converter just uses successive approximation, so low frequencies are easy. But Delta-Sigma is a different process, and does not work well at very low frequencies.
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