Audio Asylum Thread Printer
Get a view of an entire thread on one page
|For Sale Ads|
In Reply to: RE: Dynamics Measured.... posted by BigguyinATL on April 20, 2017 at 11:28:00
And if you do the same thing with the microphone at a normal distance away (say 2 feet)?
I think Inmates point is that sure, at 5 inches the scissors will make 150 db peak but at 2 feet away it will be a LOT less.
You sort of have this backwards. Sure at two feet the level will be less. but you loudspeakers are 6-7-8 feet away so compared to two feet away they have to be putting out 6dB or more output than the Coke can at 1 or two feet. 114dB adjusts down to about 104dB in a typical room - then add 6dB for the loudspeaker distance distance and adding two loudspeakers (assuming a mom placement gets you back up to 110dB peak capability.
While it could be the level that you are interested in, there is also the interest in preserving dynamics. Sure in a Public address world - the loudspeakers would have to be putting out a lot of SPL to make a coke cane sound realistic at 100 ft. So high efficiency is paramount in that application. But I feel that if we really had recordings the preserved the dynamic range of a piano or drum kit or even the bite of a reed, many audiophile stereo systems would be driven into clipping.
Another think the measurements bring out is that it is important to listen in a quiet environment to preserve dynamics. The best and most expensive listening rooms I have been in are designed for 10dBA or lower background noise levels - with the HVAC running! The standard microphone on the sound meter can't go that low but (as you see in the pic) we do make a mic that can go that low...
"The hardest thing of all is to find a black cat in a dark room, especially if there is no cat" - Confucius
"You sort of have this backwards."
Not really. His point is simply that the sound of scissors cutting paper, at some "normal" distance, say from your hands to your ears, is a very small sound, and that, as you move the microphone (or your ears) closer, it's louder. At a normal distance, it ain't anywhere near 140 dB peak.
If you want to reproduce that sound, and hear it from 8 feet away AS IF you were 2 inches away, that's a different ballgame.
BTW, regarding studio rooms... When I was in Studio D at Fantasy in Beserkeley, it was like being in heaven! Quiet, spacious, nice visual asthetics, and Alison was easy on the eyes, too. Forget recording - I could hang out in that room just to unwind or have lunch!
Anyway, regarding sound levels... Did you know that the SPL of a trumpet can be up to 200 dB at the bell of the horn?! Holy crap! Somebody told me this years and years ago. Ever since, I've wondered if most trumpet players know this, 'cause especially these days, lots of them use "clip-on" microphones on their horns. I remember recording the Buddy Rich band, and the trumpet soloist was practically eating the microphone, and it sounded like a f-ing kazoo. On the other hand, Doc Severinsen uses a Sennheiser 441, and, doesn't eat it.
I heard 150db at the bell not 200db. What was your source for that number?
I don't recall the figure but it is quite high.
This high speed video captures what they called a shock wave produced by a trumpet however a traditional shock wave is visible on the rarefied side.
The second video is a system i developed the transducers and control electronics for which here is operating in the mid 160dB's at about 21Khz and at least up to 175dB, i never saw any kind of shock wave even at those pressures (although at 175dB one could light a cigarette with acoustic friction).
I don't remember, it was a long time ago. Anyway, I play the trumpet, and it can be VERY loud at the bell. Heck, it can be very loud 15 feet away. I went to a clinic/master class given by Doc Severinsen about 3-4 years ago. He picked up a student's horn, pointed it right at me, and darn near parted my hair with a scale going up to high C.
Post a Message!
This post is made possible by the generous support of people like you and our sponsors: