# decibel rule of thumb. false apparently.



## Guitarfreak235 (Jun 8, 2012)

unless wikipedia is wrong, 10 db more, as i so often see, is NOT twice as loud. 6 db is twice as loud. 10 db is just over 3 and 20 db is 10 times as loud. so im just curious if everyone just heard 10 db is twice as loud and accepted it?

http://en.wikipedia.org/wiki/Decibel

check out the chart on the right


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## Justin Zazzi (May 28, 2012)

> This article is about the ratio of measures.


Key word here is measure. Human ears works slightly differently. Wikipedia is great for many things, but you will be able to find more relevant acoustics knowledge at audio-specific sites. I just finished a 2 hour drive home from a competition this week and I'm not going to search for them now, but they are not too hard to find. The 10db rule of thumb is fairly common.

-J


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## Guitarfreak235 (Jun 8, 2012)

Jazzi said:


> Key word here is measure. Human ears works slightly differently. Wikipedia is great for many things, but you will be able to find more relevant acoustics knowledge at audio-specific sites. I just finished a 2 hour drive home from a competition this week and I'm not going to search for them now, but they are not too hard to find. The 10db rule of thumb is fairly common.
> 
> -J


the ratio of amplitudes shows that 6db is double the intensity, and thats just science. even if someone decided hey 10db "sounds" twice as loud, we should not use something subjective to quantify something objective. wikipedia does say that the way we perceive changes in loudness is not perfect and is partly why we use the decibel scale. but when someone says something absolute like 10db is twice as loud that can be misleading because i myself took it as mathematically correct.


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## Justin Zazzi (May 28, 2012)

What evidence do you use to support this argument? I'm not being combative or arguing, but I'm really curious why you come to this conclusion or what experience you have that guides you.


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## Fricasseekid (Apr 19, 2011)

Isn't the decibel scale logarithmic? So the difference between 90 and 100 isn't the same as the difference between 150 and 160. 

No?


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## Justin Zazzi (May 28, 2012)

Halfway true. The absolute difference will not be the same, but the relative difference will be.


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## oldschool4me (Feb 9, 2013)

yea like back in the day in the early 90s we used the 6db rule....was said to gain 6db you need to double the power and sub surface space...likely incorrect but we were kids.


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## minbari (Mar 3, 2011)

oldschool4me said:


> yea like back in the day in the early 90s we used the 6db rule....was said to gain 6db you need to double the power and sub surface space...likely incorrect but we were kids.


that is not incorrect at all. -3db or halfpower point 

to gain 3db you have to double power OR double speaker surface area. so, to get 6db gain, you would have to double power AND double subs.


simple formula: 10 x log10(power A / power B)

10 x log10 ( 1000watts / 500watts) = 3.01db


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## chad (Jun 30, 2005)

minbari said:


> that is not incorrect at all. -3db or halfpower point
> 
> to gain 3db you have to double power OR double speaker surface area. so, to get 6db gain, you would have to double power AND double subs.
> 
> ...


And then, because physics always ****s you in the drive through, if you double distance you lose 6dB so double distance=quadruple power to make up.


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## minbari (Mar 3, 2011)

chad said:


> And then, because physics always ****s you in the drive through, if you double distance you lose 6dB so double distance=quadruple power to make up.


lol, absolutely............but no one said they were gonna push thier chair back. 

This is why all these discussions about power almost all academic. if you have 120watts instead of 150watts, who cares. almost not measureable let alone audible.


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## chad (Jun 30, 2005)

minbari said:


> lol, absolutely............but no one said they were gonna push thier chair back.


Physics pulls your chair out from under you... It's a damn troll.


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## MarkZ (Dec 5, 2005)

Guitarfreak235 said:


> even if someone decided hey 10db "sounds" twice as loud, we should not use something subjective to quantify something objective.


Why not? There's an entire branch of psychology/neuroscience devoted to exactly that. It's very important to objectively quantify our subjective sensory capabilities.

In this case, the confusion arises from the problem with "rules of thumb" in general. If you look at the Fletcher-Munson equal loudness contours, it will tell you EXACTLY what we perceive as "twice as loud" (within a certain variance of course). You'll find that there isn't a single number. It's strongly dependent on frequency and amplitude. For example, the curves are more compressed at subwoofer frequencies, so it ends up being closer to 6dB there, whereas at 1kHz it's closer to the 10dB "rule of thumb". At least until you get up past 90dB, and then they start diverging again.


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## Oliver (Jun 25, 2007)

:snacks::ears::whip::inout::knife::earmuffs:


http://www.youtube.com/watch?v=iy7QzvP1k2w


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## Guitarfreak235 (Jun 8, 2012)

MarkZ said:


> Why not? There's an entire branch of psychology/neuroscience devoted to exactly that. It's very important to objectively quantify our subjective sensory capabilities.
> 
> In this case, the confusion arises from the problem with "rules of thumb" in general. If you look at the Fletcher-Munson equal loudness contours, it will tell you EXACTLY what we perceive as "twice as loud" (within a certain variance of course). You'll find that there isn't a single number. It's strongly dependent on frequency and amplitude. For example, the curves are more compressed at subwoofer frequencies, so it ends up being closer to 6dB there, whereas at 1kHz it's closer to the 10dB "rule of thumb". At least until you get up past 90dB, and then they start diverging again.


you make a valid point yes subjectivity and how we perceive sound is important. and yes different frequencies are perceived differently. i was referring to a difference in loudness at a given frequency. that graph just shows how loud a frequency at a given intensity is perceived compared to a 1khz sample 

and yes it is logarithmic so the relative differences are the same.

if we can establish that perceived differences in loudness are different at different spls AND at different frequencies, we can conclude the 10db rule is a gross generalization. 6 db is truly twice as loud and should be what people are told with the disclaimer that perceived differences vary.


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## Guitarfreak235 (Jun 8, 2012)

Jazzi said:


> What evidence do you use to support this argument? I'm not being combative or arguing, but I'm really curious why you come to this conclusion or what experience you have that guides you.


im just speaking on behalf of the science behind it. a 10db gain is actually just over 3 times as loud. but the average person probably couldnt hear a 10db gain and say oh thats 3 times louder.

i guess what im trying to say is that gains in db and loudness should be discussed as scientifically as possible. despite differences in frequency perception etc.


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## Justin Zazzi (May 28, 2012)

Guitarfreak235 said:


> im just speaking on behalf of the science behind it. a 10db gain is actually just over 3 times as loud. but the average person probably couldnt hear a 10db gain and say oh thats 3 times louder.
> 
> i guess what im trying to say is that gains in db and loudness should be discussed as scientifically as possible. despite differences in frequency perception etc.


Fair enough. Please present your science. I would like to read more about it. If convincing, it would help change the way many of us think about this concept (which is your goal after all right?)


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## Oliver (Jun 25, 2007)

Jazzi said:


> Fair enough. Please present your science.


At that time I will change it from deci-BEL, to whatever your last name is [I.E. decijohnson or decijerkowicz ] <<<< latter one is pronounced yer-kev-vitch !




> I would like to read more about it. If convincing, it would help change the way many of us think about this concept (which is your goal after all right?)


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## MarkZ (Dec 5, 2005)

Guitarfreak235 said:


> if we can establish that perceived differences in loudness are different at different spls AND at different frequencies, we can conclude the 10db rule is a gross generalization.


That's not what that plot shows?



> 6 db is truly twice as loud and should be what people are told with the disclaimer that perceived differences vary.


You have no basis for saying this. Experiments have shown that the number is closer to 10dB *at 1kHz and at moderate levels*. But like I said, the Fletcher-Munson curves show that this number compresses when you change those factors.

Edit: check out the wikipedia entry for Sones. It explains the relationship between the Sone and the Phon, and a brief description of how SS Stevens (widely regarded as one of the pioneers of psychophysics) arrived at that. BTW, I would strongly recommend his book "Psychophysics" for anyone interested in using the scientific method to quantify human sensation.


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## Oliver (Jun 25, 2007)

MarkZ said:


> That's not what that plot shows?


Comprehension, it's what's for dinner


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## rich20730 (Feb 13, 2012)

Guitarfreak235 said:


> im just speaking on behalf of the science behind it. a 10db gain is actually just over 3 times as loud. but the average person probably couldnt hear a 10db gain and say oh thats 3 times louder.
> 
> i guess what im trying to say is that gains in db and loudness should be discussed as scientifically as possible. despite differences in frequency perception etc.


I think the source of confusion is that you are equating loudness with SPL.

SPL is an objective measure. An increase of 6 dB is twice the SPL. There's no disputing it. It's just math.

Loudness, however, is a subjective term which is based on how we perceive sound and is greatly influenced by frequency and absolute sound level. Consequently, loudness cannot be discussed scientifically without considering the Fletcher Munson/Robinson Dodson/Equal Loudness contours etc. as others have mentioned.

Here's some helpful information on the subject from The Sound Reinforcement Handbook by Ralph Jones:

Some people use the term "loudness" interchangeably with "SPL" or "Volume." This is incorrect since "loudness" has a very distinct, and not so simple meaning.

dB SPL

The dB may be used to describe sound pressure levels. Another term for voltage is electromotive force (EMF). The force of air pressing against the resistance of an eardrum is analogous to the force of a battery pushing electrons against he resistance in a circuit. Therefore, when a dB describes a sound pressure ratio, the "20 log" equation is used: where P0 and P1 are the sound pressures, in dynes per square centimeter or Newtons per square meter.

This equation tells us that if one SPL is twice another, it is 6 dB greater; if it is 10 times another, it is 20 dB greater, and so forth.

How do we perceive SPL? It turns out that a sound which is 3 dB higher in level than another is barely perceived to be louder; a sound which is 10 dB higher in level is perceived to be about twice as loud (Loudness, by the way, is a subjective quantity, and is also greatly influenced by frequency and absolute sound level.)

Does SPL have an absolute reference value, and therefore do "SPLs" have quantifiable meaning? Yes, generally 0 dB SPL is defined as the threshold of hearing (of a young, undamaged ear) in the ear's most sensitive range, between 1 kHz and 4 kHz. It represents a pressure level of 0.000002 dynes/cm2, which is the same as 0.000002 Newtons/m2.

One can use a sound level meter to measure the sound pressure level in dB SPL. If a test signal with a flat frequency response across the audio bandwidth, is fed through an amplifier with a flat response, and to a theoretically ideal loudspeaker with a perfectly flat response, to a listener outdoors, the result should be uniform sound pressure at all frequencies. A sound level meter set to flat response would indicate the same number of dB SPL as the test signal is swept across the audio range.

You can be certain however, that the listener will not perceive this theoretically "flat" sound system to be so. Indeed, over the years it has been demonstrated that human hearing itself does not have a flat frequency response.


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## msmith (Nov 27, 2007)

> Loudness is a subjective attribute of sound and cannot be quantified, except in a statistical sense. If a large sample of listeners is asked to adjust the strength of two signals so that one is "twice as loud" as the other one, the average power difference will be about 10 decibels, and this will be almost independent of the absolute levels of the two sounds. The unit of loudness is the SONE, and a sound pressure level of about 40 dB is defined as having a loudness of 1 sone. 2 sones is twice as loud and corresponds to about 50 dB, etc. The use of sones to measure loudness is seldom encountered except in some psychoacoustic research.
> 
> The loudness of a sound, especially a complex sound containing many frequencies, has no simple relation to its sound pressure level, and it is hopeless to try and measure relative loudnesses of different sounds by using a sound level meter. Various attempts to build a meter which measures loudness have been made over the years, but with very little success, so complicated is our hearing mechanism.


*Source: The Audio Dictionary (Second Edition), Glenn D. White, 1987 The University of Washington Press. *


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## Guitarfreak235 (Jun 8, 2012)

I figured I may be a little off with my terminology. Loudness is subjective and spl is objective. Point taken. But the curves show that 10db is not exactly true for all frequencies and levels when observed subjectively. I am not necessarily disputing what is accepted as fact but the 10bd rule doesn't seem to apply to all frequencies. If it did the equal loudness curves wouldn't change with different spls. The difference shows that at different frequencies the change in loudness is different. But it seems that people do confuse spl and loudness as I
Have. That clears it up. But I think the rule doesn't seem to hold still


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## Guitarfreak235 (Jun 8, 2012)

Ok I've figured out the problem. Loudness, amplitude, AND intensity are all different. Decibels are a measure of intensity. My assumptions are made on the assumption that spl is the same as intensity. Intensity is proportional to the square of amplitude. So 6db is twice the amplitude but not Intensity. But still.... I stand by my assertion on loudness not applying to a single 10db rule. atleast for now.


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## MarkZ (Dec 5, 2005)

msmith said:


> *Source: The Audio Dictionary (Second Edition), Glenn D. White, 1987 The University of Washington Press. *


Who is Glenn White, and why doesn't he know what he's talking about?


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## Oliver (Jun 25, 2007)

Ha Ha ha 

:laugh:


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## MarkZ (Dec 5, 2005)

Haha sorry, I probably wasn't my most tactful there. But the quote manville provided is just so full of problems, including the contradiction of paragraph 1 and paragraph 2. But honestly, I didn't get very far past the first sentence, which was a total facepalm.


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## pjhabit (Aug 12, 2008)

Guitarfreak235 said:


> I figured I may be a little off with my terminology. Loudness is subjective and spl is objective. Point taken. But the curves show that 10db is not exactly true for all frequencies and levels when observed subjectively. I am not necessarily disputing what is accepted as fact but the 10bd rule doesn't seem to apply to all frequencies. If it did the equal loudness curves wouldn't change with different spls. The difference shows that at different frequencies the change in loudness is different. But it seems that people do confuse spl and loudness as I
> Have. That clears it up. But I think the rule doesn't seem to hold still


You're concluding it's a 'stedfast rule', when even your thread title describes it as a "rule of thumb"...


> A rule of thumb is a principle with broad application that is not intended to be strictly accurate or reliable for every situation.-wiki


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## Guitarfreak235 (Jun 8, 2012)

pjhabit said:


> You're concluding it's a 'stedfast rule', when even your thread title describes it as a "rule of thumb"...


Not at all. I think even as a rule of thumb it is too general! Lol


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## msmith (Nov 27, 2007)

MarkZ said:


> Haha sorry, I probably wasn't my most tactful there. But the quote manville provided is just so full of problems, including the contradiction of paragraph 1 and paragraph 2. But honestly, I didn't get very far past the first sentence, which was a total facepalm.


What contradiction? Why was the 1st sentence so difficult for you?


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## msmith (Nov 27, 2007)

Some good reading from the *Handbook for Sound Engineers* by Glenn Ballou:

Handbook for Sound Engineers - Glen Ballou - Google Books


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## MarkZ (Dec 5, 2005)

msmith said:


> What contradiction? Why was the 1st sentence so difficult for you?


The contradiction stems from the part where he said these things can't be quantified, which he goes on to do in the second half of the first paragraph.

"_Loudness is a subjective attribute of sound and cannot be quantified, except in a statistical sense._"

By adding that qualifier, he makes this statement is either meaningless at best, or misleading at worst. It absolutely _can_ be quantified, and just because there's a variance associated with the measurement doesn't make it untrue. There's a variance with almost every possible thing you can measure in any biological system. This is no different.

I think his viewpoint is an example of why a lot of people don't understand how important and how _universal_ sensory measurements can be. When he says that these things cannot be quantified, it casts a shadow on an entire field that has blossomed since the days of Helmholtz 150 years ago.


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## Oliver (Jun 25, 2007)

"Loudness is a subjective attribute of sound and cannot be quantified, except in a statistical sense."

I took this to mean - You and I may disagree on what is loud, but, on a piece of paper I can show you what is loud.

Statistics to me is a grouping of numbers.

A baby bawling seems loud, as it rises above other noises. ( read, not an SPL thing )

Subjectivity - is per each person to me [ hey is this loud? WHAT DID U SAY ? ]


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## MarkZ (Dec 5, 2005)

But that's true for practically anything. Go measure the SPL of your car. You'll get a different answer every time. Maybe in the first iteration it's 80.34dB, then the next one is 80.38dB, then the next one is 80.21dB, etc. Why is there a variance? Well, either there's noise associated with the playback equipment, the recording equipment, the mic stand, whatever.

It's no different measuring individuals. You'll end up with a variance. This is true not only across individuals, but also within individuals (repeated measurements). Maybe the variance is more pronounced than in the SPL case (it usually is in biological systems...). But it's still a quantity.


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## Oliver (Jun 25, 2007)

> The loudness of a sound, especially a complex sound containing many frequencies, has no simple relation to its sound pressure level, and it is hopeless to try and measure relative loudnesses of different sounds by using a sound level meter. Various attempts to build a meter which measures loudness have been made over the years, *but with very little success, so complicated is our hearing mechanism.*


Without a standard or simple relation. The point is moot.

Do you agree that the bolded part is correct?


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## Guitarfreak235 (Jun 8, 2012)

Oliver said:


> Without a standard or simple relation. The point is moot.
> 
> Do you agree that the bolded part is correct?


moot as in.... open for discussion??


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## Fricasseekid (Apr 19, 2011)

So I've been following this discussion and I have no idea at what point an apparent doubling of sound occurs but I'd suspect it's less than 10db. 

But that's not my point...

I'm sick of people downplaying any boost in wattage that is less than double. Like going from 100-150 watts will accomplish nothing. People claim that a 1db boost in noise is indistinguishable. Well I call ********! What exactly am I distinguishing when I reach over to turn my volume up or down just one click? Are you suggesting that when I turn the volume on my eclipse (which goes up to 80) from 50-52 I am increasing the volume by more than 2 db? Or when I tweak my amp gain just a little it is merely psychoacoustics when I notice a change in system performance? What about the minute adjustments we make when tuning where things boil down to 1db changes? 

My personal subjective experience is that 3db is a big difference in sound level and 10db is much more than double the volume level.


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## minbari (Mar 3, 2011)

Its my feeling that 100 mph is allot more than twice as fast as 50 mph.

(doesn't make it true)

Sent from my motorola electrify using digital farts


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## Fricasseekid (Apr 19, 2011)

minbari said:


> Its my feeling that 100 mph is allot more than twice as fast as 50 mph.
> 
> (doesn't make it true)
> 
> Sent from my motorola electrify using digital farts


Sure, but notice I said "apparent volume" not SPL. So in this case subjectiveness matters. It was stated that + 10 db is what "seems" twice as loud and that just a couple decibels is a negligible difference. It is this statement that I disagree with.


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## minbari (Mar 3, 2011)

And that is why this whole argument is retarded. People are arguing what they "feel". Its like arguing religion with Christians. You will never get anywhere

Sent from my motorola electrify using digital farts


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## Oliver (Jun 25, 2007)

religion is "faith" based

This is science based

"But", by all means believe what YOU want to


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## Fricasseekid (Apr 19, 2011)

Oliver said:


> religion is "faith" based
> 
> This is science based
> 
> "But", by all means believe what YOU want to


Well my scientific observations don't concur with the findings y'all are talking about.


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## Oliver (Jun 25, 2007)

Fricasseekid said:


> So in this case subjectiveness matters.


When U enter a competition - Subjective is king 

If he hears U U win


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## Justin Zazzi (May 28, 2012)

Fricasseekid said:


> Well my scientific observations don't concur with the findings y'all are talking about.


I fail to see the science behind your observations. Please elaborate on the work you have done and how it conflicts so strongly with the rule of thumb you are trying to dispute. No troll here, just trying to see what you see (beyond gut instincts).


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## MarkZ (Dec 5, 2005)

minbari said:


> And that is why this whole argument is retarded. People are arguing what they "feel". Its like arguing religion with Christians. You will never get anywhere
> 
> Sent from my motorola electrify using digital farts


This whole damned forum is all about what we "feel". Or, more accurately, what we sense. *It is the central point of all of audio.* An accurate understanding about a) how those sensations correlate to auditory signals; and b) how those auditory signals can be manipulated to drive sensation in a certain way; is at the bottom of virtually _everything_ we talk about in this forum.

Except OT.


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## minbari (Mar 3, 2011)

Yes but a mathematical and scientific premise like a measurement doesn't have room for opinion.

How I think a sub sounds, the quality and nuisances of it are totally subjective. The measured specs are not.

Sent from my motorola electrify using digital farts


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## Guitarfreak235 (Jun 8, 2012)

Sure we can argue about subjective perceptions... But they can and have been quantified. We discussed this earlier no? The deal with phon is that it's not exact for everyone but its pretty damn close!!

Also in reality everything we experience through audio (or anything really) is really objective. Think about it for a second. The sound waves and characteristics such as spl and distortion are objective. The way our ears work is objective. Our brains and their apparent preferences are immensely complex, but still objective. Our minds and their feelings are subjective, but with objective roots in our brain. I personally don't buy into subjective reviews for audio very much because people are just too prone to have biases etc. it's been shown in psychology. We have confirmation biases etc etc. if we can plot harmonic distortion, freq response, csd, off axis response why don't we when we can cuz a number doesn't leave room for interpretation or bias! Then we can make decisions on equipment and subjectively enjoy our music 

I am obviously in the objective camp, which is why I asked about this in the first place, and some may disagree


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## MarkZ (Dec 5, 2005)

minbari said:


> Yes but a mathematical and scientific premise like a measurement doesn't have room for opinion.
> 
> How I think a sub sounds, the quality and nuisances of it are totally subjective. The measured specs are not.
> 
> Sent from my motorola electrify using digital farts


You're right. But the "scientific measurements" have been made, and the result is _approximately_ 10dB at 1kHz.  If someone comes along and says, "yeah, but to me it seems more like 6dB", the natural reaction is to ask: "ok, where's your data?"

How is this any different from the subwoofer's physical measurement? A certain sub may have an xmax of 14mm (the true xmax might even vary from unit to unit due to QC). If someone comes in and says, "Yeah, but when I watch my sub, it looks like it's only moving about 12mm". The natural reaction is to ask: "ok, where's your data?" 

We quantify things by designing an experiment and measuring the dependent variables. If the experiment is designed to answer the question that's being asked (ie. to isolate the dependent variables of interest), then it doesn't really matter what it is you're measuring.


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## Fricasseekid (Apr 19, 2011)

When you adjust your volume how many clicks do you apply up or down? 
Just what is the difference in wattage your applying to attain the desired result? Can you hear a .5db difference?


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## Oliver (Jun 25, 2007)

Fricasseekid said:


> Can you hear a .5db difference?


Audible Difference in Sound Level Blind Listening Test

Good way to find out ^^^^^ 



> Change the target here: 6dB 3dB 1dB 0.5dB 0.2dB 0.1dB


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## Guitarfreak235 (Jun 8, 2012)

MarkZ said:


> You're right. But the "scientific measurements" have been made, and the result is _approximately_ 10dB at 1kHz.  If someone comes along and says, "yeah, but to me it seems more like 6dB", the natural reaction is to ask: "ok, where's your data?"
> 
> How is this any different from the subwoofer's physical measurement? A certain sub may have an xmax of 14mm (the true xmax might even vary from unit to unit due to QC). If someone comes in and says, "Yeah, but when I watch my sub, it looks like it's only moving about 12mm". The natural reaction is to ask: "ok, where's your data?"
> 
> We quantify things by designing an experiment and measuring the dependent variables. If the experiment is designed to answer the question that's being asked (ie. to isolate the dependent variables of interest), then it doesn't really matter what it is you're measuring.


... @ 1k. the reason i posted is that i see people saying it in general not at 1k


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## MarkZ (Dec 5, 2005)

It's not a useless argument. _At least_ once every two weeks someone comes in asking whether it's worth upgrading X to Y, and invariably someone answers, "Nah, man, it takes 10dB just to double loudness, so I wouldn't bother." That **** has happened as long as I've been around here.

I'm usually the dick that says, "yeah, but 3dB is a pretty big deal too." 

Loudness is totally a discussion worth having IMO.

On that note, if loudness perception follows a power law with an exponent of about 0.3, that means that a 3dB increase corresponds to roughly a 25% increase in loudness. To me, that number doesn't seem like chicken ****. I dunno...


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## Oliver (Jun 25, 2007)

cajunner said:


> loudness is a huge indicator of quality imho, and it's rare that components known not to get loud, achieve the same level or tier people put on the higher output drivers.


Is power compression an issue as we turn our volume knobs to the right.

As heat builds in our speakers does an amplifier need more power to do exactly what it was doing only 15 minutes ago with apparent ease.


> Speaker voice coils are made of copper or aluminum. As these voice coils increase in temperature during normal operation, the DC resistance of the voice coil increases. Greater voice coil resistance means less power transfer from the amplifier. As a result, the speaker will not play as loud when it's "warmed up" as it did when it was "cold". Some speakers may exhibit 3 to 6 dB of power compression. This means that power compression can have the same effect as taking away half


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## Oliver (Jun 25, 2007)

overhung design -vs- underhung ?

1]* The underhung design which is used mostly in high-end speakers *has the coil's height smaller than the gap

2] Power handling is related to the thermal tolerance of the wire insulation, adhesive, and bobbin material, and may be influenced by the coil's position within the magnetic gap. The majority of loudspeakers use 'overhung' voice coils, with windings that are taller than the height of the magnetic gap. In this topology, a portion of the coil remains within the gap at all times. The power handling is limited by the amount of heat that can be tolerated, and the amount that can be removed from the voice coil.


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## Guitarfreak235 (Jun 8, 2012)

I think 3 db is worth considering but with people who want to double their amp power it's just not worth buying a new amp but that's just me


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## Oliver (Jun 25, 2007)

cajunner said:


> the sound of an underhung driver is correlated to it's ability to operate in a flux field of small changes in magnetic strength, the coil is short and contributes predictably to the lines of flux controlling the coil.
> 
> when you reach the limits of travel in the gap where the coil is contained in a relatively stable flux field and the BL curve drops off at the ends of stroke, you notice when an increase in power to the coil, stops increasing sound level.
> 
> Shorting rings attempt to provide the same stability to the detrimental effects of eddy currents at the ends of stroke of an overhung driver, as that is intrinsic in an underhung design.


http://www.diymobileaudio.com/forum/industry-shop-talk/143228-high-excursion-under-hung-12-a.html

I wonder if that will be the case with this one ^^^^. 

I think *NOT*, it will move a substantial amount and have a full copper sleeve ( instead of shorting rings), it is a side project for the man himself !


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## Oliver (Jun 25, 2007)

cajunner said:


> I am talking about when a speaker goes flat and distorts, as the upper limit of power response, corresponds with loudness.
> I believe there are certain ranges where we all attempt to listen, and within those ranges some drivers will lose intelligibility where others won't, but will show other signs of reaching limits.


Jacobs 12" might not be one to cutout, as-it-were !



> Who is interested in a 27-30mm linear excursion under-hung driver with a full length copper pole sleeve paired up to our new frame platform so the x-mech is 1.5x or more the linear level as well ? Mechanically damaging this driver wouldn't be on the table.Tailored with a nice mid 0.4-0.5 Q for a low F3 !


I'm looking forward to this one !!

:beerchug:epper:


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## Fricasseekid (Apr 19, 2011)

cajunner said:


> the sound of an underhung driver is correlated to it's ability to operate in a flux field of small changes in magnetic strength, the coil is short and contributes predictably to the lines of flux controlling the coil.
> 
> when you reach the limits of travel in the gap where the coil is contained in a relatively stable flux field and the BL curve drops off at the ends of stroke, you notice when an increase in power to the coil, stops increasing sound level.
> 
> ...


I'm drunk and you sound pretty ****ing smart! You must know what your talking about Mr. Wizard. Or is that the Seagrams talking?


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## Oliver (Jun 25, 2007)

He is covering the issues, Fricasseekid



> Distortion increases at a gradual rate until the driver is completely out of control and dangerously close to destructive modes.


Think coil color changing as it burns up 

The average Joe doesn't realize the damage that is occurring until it is time to replace the speaker. 

So, in real world context "hey, I like that song, turn it up !


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## Fricasseekid (Apr 19, 2011)

Word, much less drunk now. Sort of...

To put it simply: if a speaker moves, it distorts.


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## Oliver (Jun 25, 2007)

If it moves for a long period of time, whilst being played at a maximum level, you get to buy a NEW ONE !


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## Richv72 (May 11, 2012)

Well subwoofers you feel the sound as well as hear it, so its more difficult to tell.


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## Oliver (Jun 25, 2007)

The frequencies they play is definitely what allows higher distortion before becoming noticeable.


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