10 dB or 3?
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A very unpleasant dinner last night at a restaurant with a reported noise level of 84 db – about the same as a gas engine lawn mower seated at the next table – raised what is probably an elementary question. 3 db is the familiar doubling of power, and in an audio environment is a doubling of acoustic energy, I understand. However, I have read that ten db is what results in an apparent doubling of the sound level as we hear it. Is the difference attributable to something like an AGC circuit in the human auditory system? And as for RF transmitter power, does it take a ten db increase rather than 3 to effect an apparent doubling of audio amplitude in the ears on the other end of the QSO? Never mind the S meter – I mean the actual ability to hear a signal over the noise, or over the QRM. Help, anyone?
Ted, KN1CBR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Most human perception is logarithmic. A change in OVERALL LOUDNESS of
about 10 dB is perceived as twice (or half) as loud. Changes in SIGNAL TO NOISE RATIO as small as 1 dB can be the difference between copy or not. This is true for music as well as speech or CW. When mixing live sound with multiple mics on instruments and voices, once balance is achieved, very small changes in the gain for any mic are usually required to stay in balance. 73, Jim K9YC On 12/13/2018 9:16 AM, Dauer, Edward wrote: > > A very unpleasant dinner last night at a restaurant with a reported > noise level of 84 db – about the same as a gas engine lawn mower > seated at the next table – raised what is probably an elementary > question. 3 db is the familiar doubling of power, and in an audio > environment is a doubling of acoustic energy, I understand. However, > I have read that ten db is what results in an apparent doubling of the > sound level as we hear it. Is the difference attributable to > something like an AGC circuit in the human auditory system? And as > for RF transmitter power, does it take a ten db increase rather than 3 > to effect an apparent doubling of audio amplitude in the ears on the > other end of the QSO? Never mind the S meter – I mean the actual > ability to hear a signal over the noise, or over the QRM. Help, anyone? > > Ted, KN1CBR > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Edward A. Dauer
It's been 50 years since I worked in the acoustic labs at Boeing where I posed the same question. One of the specialists in the passenger accommodation section of the lab explained it this way: the human ear is a SUBJECTIVE and dynamic instrument. In other words, the perception of sound pressure level (SPL) is a function of environment, how a person feels (is the person ill or have a runny nose, etc.), the listeners temperament (is he happy or upset), the nature of the sound (does the listener like the sound or does he find it annoying), how much has the listener had to drink, etc. As for the dynamic aspect, depending on the environment, you may hear a particular sound one way but a bit differently a moment later, depending on the above factors. Another factor is that sound can be much like water leaking into a boat. Both the water and SPL increases over time depending on the opening through which the water or sound enters a space. That type of sound can be measured with instruments but difficult to assess by ear. Sound in a restaurant can be much like water in a boat, people tend to talk louder which increases the overall SPL which causes them to talk even louder. In short, the rule of thumb is that it takes about a 10 dB increase in SPL for a person to perceive a doubling in the level of the sound. 3dB is almost imperceptible with most any kind of background noise.
On a tangential note, during the late 60s the Super Sonic Transport (SST) program was in progress and NASA conducted an extensive series of tests to determine objective and subjective aspects of sonic booms. The tests were conducted at Edwards Air Force Base in California over a three month period. Boeing, Lockheed, and other institutes participated. The base was building additional housing at the time so several of the new structures were used for the tests. Three of them were fitted out like regular homes with carpeting, window shades and curtains, furniture, etc., and a couple of the houses were configured more like offices or large department stores. Some of the homes had people in them and others did not. All of the buildings were extensively instrumented, both inside and out. All of my transducers were mounted on the outside of the buildings and my recording equipment was in a double garage of one of the houses. In my building, the garage door had been replaced with a large plate glass window to simulate a store front. The mounting assembly for the glass was changed from time to time to test various mounting designs. The subjective part of the test was done with people from the local communities who sat in various rooms and filled out forms designed to rate the effects of the sounds they heard. The sonic booms were generated by F104, B58, B70, and the then new SR71/YF12 aircraft. During some of the subjective tests, a KC135 (Boeing 707) airplane was used to simulate takeoff or low fly over sounds near airports. I never read the final report(s) of the tests but a few preliminary reports made the rounds. In the case of the subjective tests, people were all over the map. In many cases, people would give radically different scores for identical tests days or weeks apart. The objective tests often produced predictable results but there were times when repeat tests produced big surprises. Temperature, humidity, wind, and even doors open of closed, made noticeable differences in the measured data. For a quick look, we taped a ball point pen to the center of the large window and mounted a paper plate on the face of a clock so the plate was driven by the second hand. When the boom hit, the pen would produce a trace on the plate showing the displacement of the window. Some of the test were done with the garage being "tuned" by judiciously opening a door. A given aircraft would hit us with a boom then the door would be readjusted and the same aircraft would duplicate the boom minutes later. The difference could be startling. During one series of identical flights the first boom displaced the window 15mm but the second boom produced a displacement of 155mm. This type of testing is very expensive so, in an attempt to reduce the costs a ten foot diameter exponential horn which was mounted on a trailer. To test the efficacy of this device, the trailer was placed near one of the houses then two positive pressure pulses of gas were produced to simulate a sonic boom. The people in the house were told the boom was from an aircraft and asked to rate it in the usual way. (A sonic boom consists of a positive pressure spike followed by a negative spike. The amplitude, shape, and timing of the spike is a function of the speed and shape of the aircraft though the shape of the spike can be modified by structural and geologic features. The tests with the horn produced only positive spikes but the shape and timing could be adjusted mechanically. One day there was a lull in testing so I stepped outside for some air. Sitting on the ground a few feet in front of the horn was the neighborhood mutt. The dog must have noticed me because it cocked its head and looked at me. The image was right out of the logo for the RCA corporation. Doug, K7CUU -----Original Message----- From: [hidden email] <[hidden email]> On Behalf Of Dauer, Edward Sent: Thursday, December 13, 2018 9:16 AM To: [hidden email] Subject: [Elecraft] 10 dB or 3? A very unpleasant dinner last night at a restaurant with a reported noise level of 84 db – about the same as a gas engine lawn mower seated at the next table – raised what is probably an elementary question. 3 db is the familiar doubling of power, and in an audio environment is a doubling of acoustic energy, I understand. However, I have read that ten db is what results in an apparent doubling of the sound level as we hear it. Is the difference attributable to something like an AGC circuit in the human auditory system? And as for RF transmitter power, does it take a ten db increase rather than 3 to effect an apparent doubling of audio amplitude in the ears on the other end of the QSO? Never mind the S meter – I mean the actual ability to hear a signal over the noise, or over the QRM. Help, anyone? Ted, KN1CBR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Edward A. Dauer
Ted,
I am not going to comment on the dB aspect, but the XYL and I have had great success in restaurants by asking the staff to turn down the music (or TV or whatever was making electronic sound). In many restaurants, it seems that the staff want to listen to *their* music over the din of patrons voices, and that only makes the situation worse. Lowering the music level will lower the overall noise level considerably. People tend to talk louder in a setting where there is loud audio background - they want to talk with their table partners over the electronic noise. I don't know how to counter the Holiday season when you have "Jingle Bells" or "Grandma got run over by a Reindeer" blasting in your ears - eat and shut up may be to only way to counter it or be branded as Grinch or Scrooge. Of course, there is always the one restaurant patron who has no concept of "inside voices" that becomes an irritant to everyone else. Choose restaurants with carpet instead of hard floors for a further decrease in ambient noise level - soft wall hangings help too. 73, Don W3FPR On 12/13/2018 12:16 PM, Dauer, Edward wrote: > A very unpleasant dinner last night at a restaurant with a reported noise level of 84 db – about the same as a gas engine lawn mower seated at the next table – raised what is probably an elementary question. 3 db is the familiar doubling of power, and in an audio environment is a doubling of acoustic energy, I understand. However, I have read that ten db is what results in an apparent doubling of the sound level as we hear it. Is the difference attributable to something like an AGC circuit in the human auditory system? And as for RF transmitter power, does it take a ten db increase rather than 3 to effect an apparent doubling of audio amplitude in the ears on the other end of the QSO? Never mind the S meter – I mean the actual ability to hear a signal over the noise, or over the QRM. Help, anyone? > > Ted, KN1CBR > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Edward A. Dauer
To add to what Don said,
Restaurant noise levels are a plague for me. With my hearing loss the noise level just shoves everything to sound like noise with no intelligence detectable. I note that some now have cc activated on TV's with sound turned down to keep background sound lowered. That allows patrons to follow sports or news programs without everyone raising their voice to compete with the TV. Background music is just noise if I want conversation with anyone. Finer restaurants go to some lengths to produce the "quiet atmosphere" for fine dining. The restaurants that cater to twenty-something crowd seem to relish in making it loud. It really gets to me when they play loud music in the restrooms -ugh. Running the ham radio in the car or truck is challenge because I need the volume too high for my wife's comfort. Do not wear a headset as this might compromise my driving (ability to detect presence of other vehicle). But then I try to operate in the "parked mode" as distracted driving is not wise. Same for cellphone use while driving (illegal in some states). 73, Ed - KL7UW http://www.kl7uw.com Dubus-NA Business mail: [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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And for us as well. I often review restaurants on Yelp and Trip Advisor,
and excessive noise will turn five stars for food and service into two or three. These places are noisy because of a cynical business philosophy that a high noise level creates excitement, and also causes tables to turn over faster. 73, Jim K9YC On 12/14/2018 8:43 AM, Edward R Cole wrote: > Restaurant noise levels are a plague for me. With my hearing loss the > noise level just shoves everything to sound like noise with no > intelligence detectable. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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There is NOTHING worse. It will turn a “5” into an “I won’t be back”. One of the upscale restaurants near me I frequent has two areas. One is the “you can’t hear yourself think much less have a conversation, but it seems like a party” space, and the other is “quiet" space. It’s the only reason it isn’t off my list … Maybe it’s age … :-)
Grant NQ5T K3 #2091 KX3 #8342 > On Dec 14, 2018, at 2:10 PM, Jim Brown <[hidden email]> wrote: > > And for us as well. I often review restaurants on Yelp and Trip Advisor, and excessive noise will turn five stars for food and service into two or three. These places are noisy because of a cynical business philosophy that a high noise level creates excitement, and also causes tables to turn over faster. > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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i get the manager and show him an app with a meter showing how hi it is ...
and suggest at some point " it could approach" an OHSA issue... ok ,OSHA O Heck Should Absent myself... and I do ... At Dayton a bunch of 8 went out... we were seated inside ....and it was obvious we would be talking to the ham seated next to us ....!!! I moved the crowd outside... great move.... 80+ to low 70s On 12/14/2018 2:28 PM, Grant Youngman wrote: > There is NOTHING worse. It will turn a “5” into an “I won’t be back”. One of the upscale restaurants near me I frequent has two areas. One is the “you can’t hear yourself think much less have a conversation, but it seems like a party” space, and the other is “quiet" space. It’s the only reason it isn’t off my list … Maybe it’s age … :-) > > Grant NQ5T > K3 #2091 KX3 #8342 > >> On Dec 14, 2018, at 2:10 PM, Jim Brown <[hidden email]> wrote: >> >> And for us as well. I often review restaurants on Yelp and Trip Advisor, and excessive noise will turn five stars for food and service into two or three. These places are noisy because of a cynical business philosophy that a high noise level creates excitement, and also causes tables to turn over faster. >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Let's wind this OT thread down at this time in the interest of keeping list SNR
high. 73, Eric Mosterator /elecraft.com/ ----- On 12/14/2018 11:51 AM, Bill Steffey wrote: > i get the manager and show him an app with a meter showing how hi it is ... > > and suggest at some point " it could approach" an OHSA issue... > > ok ,OSHA O Heck Should Absent myself... and I do ... > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Edward R Cole
In 2015 I had Shingles of the facial nerve (Ramsay Hunt Syndrome) and it caused me to lose 100% of my hearing on the right. Some came back but I have a -85 dB loss in my right ear and what I do hear is not what you hear but attenuated. Noise of any kind makes it difficult to hear and I have a pretty much world class stereo that helps greatly in hearing music but... Enter BOSE QC35 headphones... They are absolutely a Godsend when it comes to hearing. I've been using Bose headphones for years but the noise cancelling ability with these are the best yet. For computer, cell phone & TV I use its Bluetooth but for the K3s I plug in and this new generation of QC from Bose allows them to be passive or with noise reduction. As passive headphones they use no power and work just fine, they do cup the ear entirely and fit/act much like the ones I use with target practice. When plugged in, Bluetooth is defeated and when you power them on, the background sound disappears. My old Alpha is 1' from my head & on my good ear, with the Heil & Sony headsets, the fan is competing with faint signals. With the noise cancelling turned on, the fan noise is non-existent. I think I might hear the very faintest motor noise but I can't swear to it. The fan noise is totally gone. I don't think there is a microphone option when plugged in but when I use the headsets with the cell phone & I'm next to the amp, nobody I talk to can hear the fan so the noise cancelling truly works with the microphone as well. I got these from Bose as my old QC15 developed a problem and they don't repair out of production headsets but they give a generous price on a current set when you exchange your broken one. I even bought the YL a pair of the QC35 II for Christmas, they're that good. They have a 30 day trial if bought from Bose. I will say the included plug is miserably short and I had to buy a longer one from Amazon but it's a hefty cable and was inexpensive. I should add, when you turn on the noise cancelling & I'm listening to a faint CW signal, there is apparently zero loss of signal volume or quality, it's just that all the ambient sound and the sound like listening to a seashell you get with over the ear headphones just vanishes. YMMV 73, Gary KA1J > To add to what Don said, > > Restaurant noise levels are a plague for me. With my hearing loss the > noise level just shoves everything to sound like noise with no > intelligence detectable. > > I note that some now have cc activated on TV's with sound turned down > to keep background sound lowered. That allows patrons to follow > sports or news programs without everyone raising their voice to > compete with the TV. Background music is just noise if I want > conversation with anyone. Finer restaurants go to some lengths to > produce the "quiet atmosphere" for fine dining. The restaurants that > cater to twenty-something crowd seem to relish in making it loud. > > It really gets to me when they play loud music in the restrooms -ugh. > > Running the ham radio in the car or truck is challenge because I need > the volume too high for my wife's comfort. Do not wear a headset as > this might compromise my driving (ability to detect presence of other > vehicle). But then I try to operate in the "parked mode" as > distracted driving is not wise. Same for cellphone use while driving > (illegal in some states). > > 73, Ed - KL7UW > http://www.kl7uw.com > Dubus-NA Business mail: > [hidden email] > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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