big K Posted July 11, 2003 Share Posted July 11, 2003 http://www.dynacord.de/pdf/55_459_download.pdf the above pdf file states at the bottom of page 3 that: sound far by 3dB in the near field where as clasicial designs fall by 6Db in the farfield. both for a doubleing of distance I assume this near or far field would be unimportant, I don't see why sound would drop of differently between 5m -> 10 m , then if would for 20m -> 40m. Okay I almost have a hold on this whole dB thing, but as far proveing or disproving the above how does the math work? Kevin Nemrava thanks all. Link to comment Share on other sites More sharing options...
flyscots Posted July 11, 2003 Share Posted July 11, 2003 Sorry I'm not entirely sure if I understand what you're asking, but I had a quick read so here goes: The sound pressure level at 10m would be 6dB lower than at 5m The SPL at 40m would be 6dB lower than at 20m, so you're right with that. Dynacord are saying that their systems do not drop by the usual 6dB, but only by 3dB for each doubling of distance. They go into the reasons for this on the pdf. I probably didnt help you any there did I? Link to comment Share on other sites More sharing options...
Philip OKeefe Posted July 11, 2003 Share Posted July 11, 2003 Flyscots is correct. In a free field (reflection free) environment, sound drops by 6 dB with each doubling of the distance. It's called the Inverse Square Law... sound levels drop at the inverse of the square of the distance from the source. IOW, 6 dB every time you double the distance. That's basic physical aocustics. I didn't read the pdf, but I will try to later (when I have more time... as if I HAD any time... swampped right now...) BUT I will say that if someone is claiming they have a way to avoid the inverse square law in a free field environment, I would be very skeptical... Link to comment Share on other sites More sharing options...
Curve Dominant Posted July 12, 2003 Share Posted July 12, 2003 [quote][b]sound far by 3dB in the near field where as clasicial designs fall by 6Db in the farfield. both for a doubleing of distance[/b][/quote]That statement seems too vague to be meaningful. Maybe something got lost in the translation. That, or an over-zealous ad copywriter decided to get creative with interpretations of scientific laws...Can you imagine that?? Eric Vincent (ASCAP) www.curvedominant.com Link to comment Share on other sites More sharing options...
big K Posted July 13, 2003 Author Share Posted July 13, 2003 That was basicly my interpitation of the situation. I think they are talking out of there ass. I know that even if you have the sound radiate in to only 1/2 of a sphere, or even less then that as in a line array. THE LAW STILL HOLDS. Yes the power is higher, in a directionial array then in a shere/point source, but doubleing the distance still results in 6 dB loss. I also have a sales man tell me the same think (must have been after reading that) that E/V broke the laws of phyics, - and when on to describe this. I know also that the inverse square law not only applies to sound, but light intescity, gravity and electro/ magnetic waves as well. Why can people get away with so much crap in marketing? If I get the chance I am going to phone them , .. and if that doesn't work I am showing up with a SPL meter at there next demo day. thanks all Kevin nemava Link to comment Share on other sites More sharing options...
EXAGON Posted July 13, 2003 Share Posted July 13, 2003 I did not read the link but with phase jokes almost anything is possible. Someone just invented a speaker system which can be heard only in a precise place and it's SILENT in the rest of the room! Features Are Not An Opinion. (John Hope, 2003) http://johnhope.blogspot.com/ Addresse: UIPLPPICDSS Ufficio Internazionale Per La Presa Per Il Culo Dei Sbruffoni Statunitensi Att. Tua Sorella Codice Mavapigliatelindomo Pirla Chi Legge Link to comment Share on other sites More sharing options...
Hendmik Posted July 13, 2003 Share Posted July 13, 2003 [quote]Originally posted by tron: [b]I did not read the link but with phase jokes almost anything is possible. Someone just invented a speaker system which can be heard only in a precise place and it's SILENT in the rest of the room![/b][/quote]Yeas. It's the audio equivalent to light focussed into a laser. There are no ambient side effects and the listener, at 100 yards, hears the signal as if they were wearing headphones. At that distance, it can focus to about 1 foot diameter. The stage monitoring implications are obvious. But think of the marketing potential. You could feasibly broadcast an ad about a certain product, audible only to those standing in front of the rack in a store. Or a Baseball coach talking to the pitcher, etc. Really cool stuff. In 20 years any moving coil tranducer will be completely out moded. Since microphones are built on the same technology as speakers, think what laser guided mics will do to mic bleed or isolation in the studio. Welcome to the future. Whenever you find that you are on the side of the majority, it is time to reform. Mark Twain (1835-1910) -------------------- Reporter: "Ah, do you think you could destroy the world?" The Tick: "Ehgad I hope not. That's where I keep all my stuff!" Link to comment Share on other sites More sharing options...
loudist Posted July 14, 2003 Share Posted July 14, 2003 Its called the [url=http://holosonics.com]audio spotlight[/url] . It works on the elasticity physics of air to create audible frequencies, these aren't the only guys doing this... Link to comment Share on other sites More sharing options...
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