I'm sure there are lots of honest (as well as intentional) mistakes in the news. So...
-20 dBm (0.00001 W) vs. 1/10 mW vs. 1/10W -- just minor differences. Obviously, there are bigger (as well as more subtle) blunders in the news than 30 decibel speech. Perhaps speech levels were measured by the reporter at a distance... perhaps the length of a soccer field? Or the "decibel" reference wasn't the standard 20 uPa -- it didn't state 30 dBA or 30 dB SPL. Nowadays, I do hear and see more errors regarding "dBm" because impedance (600 ohms standard for dBm) is rarely accounted for. This, then, often creates confusion when teaching the difference among line-level, mic-level, dBm, dBv, dBu, dBV, etc. I think I'll go into journalism... few will notice my mistakes. Best, ELC ________________________________ From: David Pickett <d...@fugato.com> To: Eric Carmichel <e...@elcaudio.com>; Surround Sound discussion group <sursound@music.vt.edu> Sent: Saturday, November 24, 2012 12:33 PM Subject: Re: [Sursound] Quietest place on Earth revisited At 08:46 24-11-12, Eric Carmichel wrote: >Back in October (Sursound Digest, Vol 51, Issue 24, to be exact) there >was a post regarding places to visit, and Orfield Labs, the "quietest >place on Earth" was showcased. It was then pointed out that the BBC >article (link below) said, "an average conversation runs at about 30 decibels." > >I asked Steve Orfield, who owns/operates Orfield Labs, where this >figure might have come from. Steve politely replied with, "We aren't >responsible for the levels. We always reference 65.5 dBA, from the old >articuatlion index standards and ANSI." > >So, I suppose the "30 decibel" level came from an unreliable source -- >seems to happen a lot since the advent of the Internet (that we all >know is an alien conspiracy). The BBC does not always check facts. http://news.bbc.co.uk/2/hi/programmes/fast_track/9766517.stm See this item on whether electronic gadgets can actually affect the safe operation of a plane during take off or landing, where a scientist making the measurements mistakenly tells a journalist that -20dBm = 1/10 mW without being challenged. Later the journalist quotes this as 1/10 W. I wrote to point this out, and received a "thank you for your interest" reply... David -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20121124/d5838e46/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
