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  #31  
Old 01-17-2019, 10:05 AM
Earl49 Earl49 is offline
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Originally Posted by JimCA View Post
....Why is it that several report (Kramster, Kindness, Captain Jim's soundtest report listener's, me and others) that the X7 sounds louder than the larger Emeralds?
Because it is hard to quantify psychoacoustic perceptions of subjective things like loudness and tone quality. I hear the differences too, but putting a meaningful number to them is a challenge. I certainly applaud Alistair's attempt.

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Originally Posted by ac View Post
If you have a phone and are curious how loud your guitars are ...
ac, I've looked at all those apps since I nearly always have my iPhone with me, but don't always carry my $6000 sound meter. SPLnFFT is my favorite. The short answer is that they are seriously limited by the phone's on-board microphones. They can give decently accurate results -- if you also spend about $300 for an external microphone to plug into the headset jack, and assuming your phone has a jack. Newer iPhones don't have an external jack.

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Originally Posted by JimCA View Post
....Maybe it's just that "Loudness is a complex issue"?
I said this was complicated. Byudzai showed a set of equal loudness curves, where the relative "loudness" of low, middle, and high frequencies are shown on continuous lines at various levels. Those curves were developed under controlled laboratory conditions by juries of listeners who rated the subjective loudness of each level and frequency on each curve.

There are six acoustics textbooks sitting on my desk right now, each with multiple chapters discussing sound quality, measurement, loudness, and how to quantify noise in general. So just imagine the challenge that I face trying to explain sound and noise levels to a City Council at a public hearing. You introduce a bunch of concepts (like A-weighting and averaging levels over time) to fairly assess the overall situation versus the one aspect that people are concerned about - momentary levels created by one particular sound.

One recent example: a truck terminal next to a trailer park. It seems an obviously incompatible situation on the surface. But those homes are only 500 feet from the interstate, with frontage on a road that has significant industrial truck traffic already, under the flight pattern of the airport, and about 1500 feet away from major railroad tracks. There is plenty of background noise in the area already, and overlaying the expected noise from a few dozen trucks per day showed no net increase in the area. That was NOT a popular conclusion with the residents....
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  #32  
Old 01-28-2019, 12:29 AM
casualmusic casualmusic is offline
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Would it matter if this test is dBA or dBC?

Thanks.

.

Last edited by casualmusic; 01-30-2019 at 10:18 AM. Reason: deleted befuddled ramling
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  #33  
Old 01-28-2019, 03:21 PM
Earl49 Earl49 is offline
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Originally Posted by casualmusic View Post
.......Would it matter if this test is dBA or dBC?
Yes it would. A-weighting rolls off the very low frequencies to better correlate human hearing and judgment of loudness to the meter's reading. It is essentially the inverse of equal loudness contours. C-weighting is essentially uncorrected (except for the most extreme highs and lows) and better reports content with low frequencies. For example, dBC is used by many noise ordinances when dealing with amplified music and industrial noises, where dBA would definitely under-report the levels versus the actual perceived annoyance. The Wikipedia link that I provided earlier show a graphic with the relative corrections of dBA, dBC, and others.

The best way I've come up with to explain how we selectively hear higher frequencies better is : It doesn't matter much to your survival if you hear distant thunder or a roaring waterfall. It makes a huge difference hearing the twig snap nearby as the Grizzly bear sneaks up behind you!
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  #34  
Old 01-30-2019, 10:11 AM
casualmusic casualmusic is offline
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Earl.

Thanks for the clarification. Guess it's less complicated than I thought.
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