tag:blogger.com,1999:blog-3057869926275243678.post3346806969317229320..comments2024-03-07T17:15:19.426-08:00Comments on Lies, Damn Lies, and Startup PR: Acoustic NonlinearityStartupPRhttp://www.blogger.com/profile/10863632782404121915noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-3057869926275243678.post-73942151810131208752020-01-06T02:55:36.903-08:002020-01-06T02:55:36.903-08:00Hi, awsome explanation about sound wave propagatio...Hi, awsome explanation about sound wave propagation in the air. I just want to point out that you shoud write "sound preassure" in your formulas, not just "preasure", because I thought about air preasure at ground level at first. And I have add the number 100000 Pa. I think I am not the only one person which have made that assumption.<br /><br />I would like a little bit more of explanation in these cases, please, explain it with formulas:<br />1. How energy of the sound relates to frequency and sound preasure?<br />2. How energy spreads in air in the linear distance?<br />3. How sound energy disipates after nolinearity starts? How it becomes converted to heat?<br /><br />Thank you in advance.<br /><br />By the way, now I understand why most animals and humans hear in low frequencies 20 - 20 000 Hz. It just can transfer longer distances in linear way. So sound is not distorted and it is possible to hear original sound.Tomashttps://www.blogger.com/profile/08224155579878102156noreply@blogger.comtag:blogger.com,1999:blog-3057869926275243678.post-30230962808587561392018-11-21T22:10:11.950-08:002018-11-21T22:10:11.950-08:00Looking at Szabo, the numerator is Density * Speed...Looking at Szabo, the numerator is Density * Speed^3, which is the same as Impedance * Speed^2, as Impedance = Density * Speed, so I think the original equation is correct, just stated slightly differently than Szabo. I added the equations as an image at the end of the post, including the variation for including gain of a focusing transducer.StartupPRhttps://www.blogger.com/profile/10863632782404121915noreply@blogger.comtag:blogger.com,1999:blog-3057869926275243678.post-9490828307855643372018-11-20T23:55:14.076-08:002018-11-20T23:55:14.076-08:00Ronnie. Thanks for your comment and pointing this ...Ronnie. Thanks for your comment and pointing this out. Once I have access to my copy of Szabo I'll check the equation and correct if needed (I want to check it's Impedance * Velocity^3 or Density * Velocity^3, I use Impedance in the equation above, not density). And yes you are right it's plane wave this deals with, I wanted to keep it simple for this description. As uBeam had claimed they would transmit at 145 to 155 dB, those were the numbers I started with here, as they would focus from there increasing the amplitude, or at least balancing out the loss in air (on average, there will be near field peaks and troughs), so it will for the most part only get worse as it propagates.StartupPRhttps://www.blogger.com/profile/10863632782404121915noreply@blogger.comtag:blogger.com,1999:blog-3057869926275243678.post-69911509836152755062018-11-20T01:50:08.036-08:002018-11-20T01:50:08.036-08:00Just like to point out that there is an error in t...Just like to point out that there is an error in the last equation from Szabo. <br /><br />Saturation Pressure = ( Acoustic Impedance of Air * Sound Velocity in Air ^ 2 ) / ( 2 * Beta * Frequency * Distance )<br /><br />The Sound Velocity in Air should be cubed not squared. <br /><br />Also, as a general note, the above deals with a plane wave, for uBeam the situation is focusing and there is a minor change to the equation by including the gain of the transducer. This is included in Szabo. Ronnie Pickeringnoreply@blogger.comtag:blogger.com,1999:blog-3057869926275243678.post-19538858296739149172017-07-16T08:49:01.848-07:002017-07-16T08:49:01.848-07:00Tim. I assume from your comment you mean for wirel...Tim. I assume from your comment you mean for wireless power delivery promises? In terms of 'multi-watt, multi-meter, multi-device, at anything safe and vaguely efficient, and not monstrously expensive' then the answer is 'no I don't think it's at all possible'. The more of those you drop, the easier it gets - for example, drop 'safety' as a factor as RF charging you could do tomorrow, but I wouldn't want to be around it. Check out some of my other articles on Energous to see my opinion of RF charging.StartupPRhttps://www.blogger.com/profile/10863632782404121915noreply@blogger.comtag:blogger.com,1999:blog-3057869926275243678.post-25196477761001603942017-07-16T02:51:36.788-07:002017-07-16T02:51:36.788-07:00Very good article, thanks! I'm impressed that ...Very good article, thanks! I'm impressed that such smart engineers actually tried to make this work...<br /><br />Do you think that any other type of technology could actually deliver these promises? Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3057869926275243678.post-83879414583554978972016-05-11T08:43:54.642-07:002016-05-11T08:43:54.642-07:00Hey this is Josh Constine from TechCrunch. I'd...Hey this is Josh Constine from TechCrunch. I'd like to speak with you about your claims. Can you contact me at joshc@techcrunch.com or (585)750-5674? Thanks! Josh Cosntinehttps://www.blogger.com/profile/03611196334334384824noreply@blogger.com