Re: MD: decibel scale
Since this topic is continuing and I have nothing better to do before the Vision channel starts on cable at 4am, I'll post this from my Wharfedale speaker manual: [anything in square brackets like this is my own "witty" comments]. Very Faint: 0dB- threshold of hearing 6dB- human breathing [assuming you don't wheeze] 10dB- rustle of leaves in breeze [not breaking branches in hurricane] 20dB- average whisper Faint: 30dB- Average domestic background level- no music playing 40dB- Very soft radio music playing in house Moderate: 50dB- Average office [presumably one where eveyone isn't chatting] 60dB- River or streamside, running water [no not Niagara Falls] Loud: 70dB- Typewriter or computer print room [obviously not inkjet / laser] 80dB- School playground or cafateria at break time Very Loud: 90dB- Noisy factory or noisy urban street with lorries [should use rail] 100dB- Car horn at 10 feet way [3 meters] Deafening: 110dB- Accelerating motorcycle at 10 feet away, avaerage discotheque 120dB- Threshold of feeling. Rock concert. 130dB- Threshold of pain 140dB- Near jet engine during power take-off [distance not specified] People at home listen to classical music at an average level of 80-85dB, rock music at 90-95dB, and most parties start at around 80dB and run up to 110dB beyond which they attract police attention. They go on to mention most speakers produce a sound level of 88dB from 1W at 1 meter, and doubling the distance to 2m requires twice the power so 1W would give 85dB at that distance. It then mentions the "smallest increase in loudness" takes 3dB or twice the power, and to increase the loudness two-fold takes 10 times the power, and goes on to warn how and why an over-driven low power amp will destroy your speakers much quicker than an amp with plenty of watts driving the speakers to, or even beyond their rating provided the signal isn't clipped. I do care about my ears and worry that I sustained a level that must have been 105dB average at my listening distance for over half an hour when the workers next door were hammering and drilling on the wall. I know it's not clever, I just wanted to drown out the noise. At least there was no perceptible distortion so the workers got reasonable quality sound (given a wall 'tween us :-) Cheers, PrinceGaz -- "Hey, I've got free 0800 net connection via X-Stream, the banner has crashed so I might be able to stay on all weekend! Yahoo!!! No, not the freebie email provider. Anyway I'm gonna watch Vision on cable and fill my head full of religious 'goo' as someone said :-)" Email: [EMAIL PROTECTED] Website: http://website.lineone.net/~princegaz/ ICQ: 36892193 - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale (was analog follow-up question)
=== = NB: Over 50% of this message is QUOTED, please = = be more selective when quoting text = === It has to come out the same either way. Sort of like when you use the DB formula and use power as a reference or use voltage as a reference. Since power P = V^2/R and R is constant, if you reference the voltage you need to use 20 log and if you reference power it is 10 log. It comes out the same either way. 3 db is double the power and a perceptible change in the perceived volume. Her is some info on it I found on the web http://www.neurophys.wisc.edu/~ychen/textbase/s1-p6.html Ralf Kuchenhart wrote: > > Ian Horsey schrieb: > > > All there is to know about dB : > > > > The sound intensity level B (beta) is given by (10dB) x log I / Io > > > > [...] > > > Back to ordinary dB - an intensity increase of a factor of two leads to a > > 3dB increase in sound intensity level. This change is barely perceptible to > > the human ear, and most people usually equate an increase of 8 to 10dB in > > sound intensity level to a doubling of loudness. > > > > So there is a point in doing a degree in Electronic Engineering! Hooray! > > Well, that's what you learn with an degree in Electronic Engineering, if you had > some lessons in acoustics you would learn something more (or different?) > > I don't know the exact Englisch words for "Schalleistungs(pegel)" and > "Schalldruck(pegel)". I would say sound power and sound pressure. > > The formular for sound power level is 10(dB)* log (I/Io), but the formular for > sound pressure is 20(dB)*log (p/p0). If you regard the (electrical) power you > need in your amps and to drive the speakers, your formular is absolutely right, > Ian, but if you regard the electric level you record from the microphone, you > have to use the formular for the sound pressure. Therefore, the step of 1 bit in > the PCM code is always 6(.02) dB, not 3(.01) dB. > > Ralf > > - > To stop getting this list send a message containing just the word > "unsubscribe" to [EMAIL PROTECTED] -- Jim Coon Not just another pretty mandolin picker mailto:[EMAIL PROTECTED] If Gibson made cars, would they sound so sweet? My first web page http://www.tir.com/~liteways/ - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale (was analog follow-up question)
Ralf Kuchenhart wrote: (or schrieb) >The formular for sound power level is 10(dB)* log (I/Io), but the formular for >sound pressure is 20(dB)*log (p/p0). If you regard the (electrical) power you >need in your amps and to drive the speakers, your formular is absolutely right, >Ian, but if you regard the electric level you record from the microphone, you >have to use the formular for the sound pressure. Therefore, the step of 1 bit in >the PCM code is always 6(.02) dB, not 3(.01) dB. When you say electric level Ralf, you need to be a little more specific. The voltage level follows the 20log... formula, but if you measure the power being delivered by the microphone to the preamp, it still follows the 10log... formula, as any electrical power ratio always will. When talking PCM code, you are always referring to digital representations of voltage, not power. That is why every bit adds 6.02dB of dynamic range. By doubling the available voltage range (adding 1 bit of resolution) we are quadrupling the available power range, and this solves in the 10log... formula. -cb - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale (was analog follow-up question)
Ralf Kuchenhart wrote: >> As a rule of thumb, 10dB is very close to an average person's perception of >> doubled volume. > >Only a rule of thumb? Have a look onto the "sone" scale and it's formular (I >don't have it at hand) when converting between sone and dB. A sound of 2 sone is >exactly twice as loud as a sound of 1 sone (at least for an average person...). That's why it's only a rule of thumb. The sensitivity of our ears changes quite dramatically across the frequency range, and the rate of change of perceived volume with power also changes with frequency and absolute sound pressure level. There is no specific number of decibels that equates to doubling volume, unless a specific frequency, absolute SPL, and subject are given. -cb - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 * Hannes Rohde <[EMAIL PROTECTED]> on Fri, 20 Aug 1999 | Now, that's a short concert! Shortest rock show I attended was Green Day on the Boston Esplanade. 20 minutes or so and then the MDC pulled the plug. | Another rule-of-thumb, though not really usefull: If it hurts in | your ears, it has been damaging your ears. The level damaging your | ears is lower than the pain-causing level. Pain is your body's way of saying, "STOP THAT, DAMNIT! THAT HURTS!" -BEGIN PGP SIGNATURE- Version: GnuPG v0.9.10 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE3vgfxgl+vIlSVSNkRAqmHAJ4yzXVKglQwgZFiZTOsSYpEWikLQgCfXke9 gLq04Hf5LaYUOJR48oUiBvg= =simt -END PGP SIGNATURE- -- Rat <[EMAIL PROTECTED]>\ When not in use, Happy Fun Ball should be Minion of Nathan - Nathan says Hi! \ returned to its special container and PGP Key: at a key server near you! \ kept under refrigeration. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale (was analog follow-up question)
Ian Horsey schrieb: > All there is to know about dB : > > The sound intensity level B (beta) is given by (10dB) x log I / Io > [...] > Back to ordinary dB - an intensity increase of a factor of two leads to a > 3dB increase in sound intensity level. This change is barely perceptible to > the human ear, and most people usually equate an increase of 8 to 10dB in > sound intensity level to a doubling of loudness. > > So there is a point in doing a degree in Electronic Engineering! Hooray! Well, that's what you learn with an degree in Electronic Engineering, if you had some lessons in acoustics you would learn something more (or different?) I don't know the exact Englisch words for "Schalleistungs(pegel)" and "Schalldruck(pegel)". I would say sound power and sound pressure. The formular for sound power level is 10(dB)* log (I/Io), but the formular for sound pressure is 20(dB)*log (p/p0). If you regard the (electrical) power you need in your amps and to drive the speakers, your formular is absolutely right, Ian, but if you regard the electric level you record from the microphone, you have to use the formular for the sound pressure. Therefore, the step of 1 bit in the PCM code is always 6(.02) dB, not 3(.01) dB. Ralf - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale (was analog follow-up question)
Colin Burchall schrieb: > As a rule of thumb, 10dB is very close to an average person's perception of > doubled volume. Only a rule of thumb? Have a look onto the "sone" scale and it's formular (I don't have it at hand) when converting between sone and dB. A sound of 2 sone is exactly twice as loud as a sound of 1 sone (at least for an average person...). Ralf - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale
Hannes Rohde wrote: > > Stainless Steel Rat wrote: > > > I used to have a little table that listed how long you could listen > > to certain things before permanent damage occoured. Two of the > > high end sounds were "rock concert", 110dB, 7 minutes > > Now, that's a short concert! Still probably too long. > Remind me to take my ear plugs with me to Cologne tonight. I forgot > them yesterday but it was great fun anyway. Anyone else here going > to Cologne to visit the PopKomm music fair? What did you say? What? -- Jim Coon Not just another pretty mandolin picker mailto:[EMAIL PROTECTED] If Gibson made cars, would they sound so sweet? My first web page http://www.tir.com/~liteways/ - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale
Stainless Steel Rat wrote: > I used to have a little table that listed how long you could listen > to certain things before permanent damage occoured. Two of the > high end sounds were "rock concert", 110dB, 7 minutes Now, that's a short concert! Another rule-of-thumb, though not really usefull: If it hurts in your ears, it has been damaging your ears. The level damaging your ears is lower than the pain-causing level. Remind me to take my ear plugs with me to Cologne tonight. I forgot them yesterday but it was great fun anyway. Anyone else here going to Cologne to visit the PopKomm music fair? Bye, Hannes _.-._.-> If you don't move, you don't Mojo! - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale (was analog follow-up question)
All there is to know about dB : The sound intensity level B (beta) is given by (10dB) x log I / Io Io is a refernece intensity chosen to be 10E-12 Watts per metre square, the approximate threshold of human hearing at 1000Hz. If the intensity of a sound wave equals Io, its sound intensity is said to be 0dB. An intensity of 1 watt per metre square is equivalent to 120dB. However, the ear is not equally sensitive to all frequencies in the audible range, and this gives rise to the dBA scale. This scale de-emphasizes the low and very high frequencies and uses the midrange frequencies to give a better indication of the sound level you are hearing. Back to ordinary dB - an intensity increase of a factor of two leads to a 3dB increase in sound intensity level. This change is barely perceptible to the human ear, and most people usually equate an increase of 8 to 10dB in sound intensity level to a doubling of loudness. So there is a point in doing a degree in Electronic Engineering! Hooray! Ian (going to put his in-car MD player in to his new car :-) ) - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale (was analog follow-up question)
David W. Tamkin wrote: >The rodent wrote, > >| More directly useful to >| you, doubling volume (energy) is 10dB, so a 20dB sound is twice as loud as >| a 10dB sound, and a 110dB sound is twice as loud as a 100dB sound. > >That doesn't sound right. Speaking in the purely subjective terms of perceived volume, it is generally observed that approximately 9 times the power equates to double the volume. It definitely is NOT right to factor perceived volume linearly with energy. >As to doubling the volume, that's subjective, isn't it? "Twice as loud" is >a lot like "twice as dark" or "twice as happy." As a rule of thumb, 10dB is very close to an average person's perception of doubled volume. -cb - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 * "David W. Tamkin" <[EMAIL PROTECTED]> on Thu, 19 Aug 1999 | A *reading* of 20 dB would have ten times as much energy reaching the sensor | (or reaching the ear) as a reading of 10 dB. An *increase* of 20 dB would | mean 100 times the energy (or really the power) of the previous reading. Yeah, that's right. I had the right log, but I was thinking exponential for some reason (which would explain why my description did not sound quite right). As far as the average listener is concerned, 90dB is loud, 100dB is LOUD, 110dB is REALLY EFFING LOUD, and 120db is OHMYGODTURNITOFFMYEARSAREGOINGTO EXPLODE!!!H! :) I used to have a little table that listed how long you could listen to certain things before permanent damage occoured. Two of the high end sounds were "rock concert", 110dB, 7 minutes, and "jet airliners taking off", 120dB, 20 seconds. -BEGIN PGP SIGNATURE- Version: GnuPG v0.9.10 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE3vLhQgl+vIlSVSNkRAq5lAKCPuuTSOcJzOKn5sLpjLUuL/pJJdwCgtvoW NsowZb/8twgs5kqgw6iqss8= =XfSr -END PGP SIGNATURE- -- Rat <[EMAIL PROTECTED]>\ Happy Fun Ball may stick to certain types Minion of Nathan - Nathan says Hi! \ of skin. PGP Key: at a key server near you! \ - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale
Let me rephrase this: after speaking about a 3.01 dB *increase*, I said, | 20 dB has ten times the energy reaching the sensor (or ear) as 10 dB. A *reading* of 20 dB would have ten times as much energy reaching the sensor (or reaching the ear) as a reading of 10 dB. An *increase* of 20 dB would mean 100 times the energy (or really the power) of the previous reading. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: decibel scale (was analog follow-up question)
I was under the impression that a voltage level increase of 6db is roughly 2x, and 20db is bang on 10x. Either way it's definetly a logarithmic measure. In terms of the power involved, given constant resistance/impedance, that is the square of the voltage, or in dB terms +3dB is twice the power and +10dB ten times. So an 18-bit DAC has a theoretical resolution of 262,144 steps thus the 108dB dynamic range (200,000 steps being roughly 106dB). I think what Nathan / "the Rodent" said about a ten-fold power increase (10dB) being needed to make something sound twice as loud may well be true. The booklet from a fairly well-respected speaker manufacturer (Wharfedale).agrees. Anyone know anything about this. Further tests show when my Akai amps' thermal cut-out tripped, I was probably averaging aroung 50W RMS with peaks of near 200W RMS-- which might have clipped or might not by my amp.The AC reading on my meter with music was half that of a 1KHz test-sig under the same conditions. I guess that explains the Akai getting all hot and bothered. Cheers, PrinceGaz -- "if it harms none, do what you will" Email: [EMAIL PROTECTED] Website: http://website.lineone.net/~princegaz/ ICQ: 36892193 From: David W. Tamkin <[EMAIL PROTECTED]> > S.S. Rat wrote: > | More directly useful to > | you, doubling volume (energy) is 10dB, so a 20dB sound is twice as loud as > | a 10dB sound, and a 110dB sound is twice as loud as a 100dB sound. > > That doesn't sound right. > > An increase of 10 dB means ten times as much energy. Doubling the energy > would be an increase of 10*log(2) [common log, base 10, that is], or about > 3.01 dB. 20 dB has ten times the energy reaching the sensor (or ear) as > 10 dB. And I guess even at that we should say "power" rather than "energy". > > As to doubling the volume, that's subjective, isn't it? "Twice as loud" is > a lot like "twice as dark" or "twice as happy." - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
MD: decibel scale (was analog follow-up question)
The rodent wrote, | More directly useful to | you, doubling volume (energy) is 10dB, so a 20dB sound is twice as loud as | a 10dB sound, and a 110dB sound is twice as loud as a 100dB sound. That doesn't sound right. An increase of 10 dB means ten times as much energy. Doubling the energy would be an increase of 10*log(2) [common log, base 10, that is], or about 3.01 dB. 20 dB has ten times the energy reaching the sensor (or ear) as 10 dB. And I guess even at that we should say "power" rather than "energy". As to doubling the volume, that's subjective, isn't it? "Twice as loud" is a lot like "twice as dark" or "twice as happy." - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
