3dB. What it is.

[JeffB]

Got curious after the on going internet debate that seems to carry on in every guitar forum.

The only way I could do it was to use my Mesa LS and switch from 10w to 100w with out adjusting any controls.

I couldn't turn up too loud, it was after midnight and my wife and daughter are sleeping down the hall. You can hear the strings clicking while being strummed in both 10 and 100w modes.

I ran the Mesa LS through a Mesa horizontal 212 recto cab with V30's. I had the rectifier in diod mode and the amp in full power mode not tweed. I used a PRS Swamp Ash Special with a Dimarzio 36th anni in the neck and a Dimarzio AT-1 in the bridge.

I used a Shure 57 pointed casually in the general direction of the out side of the speaker about 4"-5" away from the grill cloth.

The clips not really about tone/sound quality, so excuse if its a bit fizzy or not eq'd right. I mixed with cheap headphones. Its also not about wicked shred ability. I played two riffs, one on the neck and one on the bridge and played each riff in both 10w and 100w. I tried to play evenly through each mode. I'm not a machine. 100w's is more dynamic even at these very quiet volumes and its harder to not be affected.

Each riff starts out in 10w mode then there's a big clunk or pop where I switch up to 100w.

The volume I played at would be no more than conversation level. I'm softly spoken and mumble. 10w mode would be a conversation at about 3dB lower than the 100w mode

As a volume reference I left my creaky chair and hard disk recorder button pushing noises in the mix at the end.

The db meter on my recording device pretty much show's about 3dB difference through each example in 10 and 100w modes.

 

My take on it all. 3dB is quite a bit when listened back to like this. I'm surprised by the difference in play back particularly on the more rock riff.

But in the context of the very low volume I was playing at, through a 212 cab, and the fact that with the LS it is easy to back the volume down in 100w mode to the same level as 10w and not lose anything, just volume, the debate between big amps v small amps is over for me. I dont have to think about it any more.

 

Ive got a theory about pick ups, parametric and graphic eq's, tone stacks and cheap guitar cables that I want to get started on.

 

Here's the link to what Ive been rambling on about.

3dB link

[JeffB]

Here's the link.

My link

[NoNameBand]

3db is the Audio industry standard for measuring volume. 3db is the increment used as this is the amount of volume needed for the average human to hear an increase in volume. In order to get an increase of 3db in a PA system for example, you would need to double the power. However, watts are like horsepower. Just because your car/truck has 300 horsepower, doesn't mean you will always Use 300 HP. The same with audio equipment. Its a way of measuring/comparing audio equipment. An amp rated at 100 watts rms @8 ohms w/3db headroom at 89db @ 1watt sensitivity, gives you a basis of it's capacity.

 

In other words, this amp will produce 89db at 1 watt. Using the doubling method: 91db = 2 watts, 94db = 4 watts, 98db = 8 watts, 101db = 16watts, 104db = 32 watts, 107db = 64watts, 111db = 128watts. So in this example, the amp will achieve a little over 107db w/3db headroom means up to 111db basically.

[rjsanders]

what were the volume settings & actual output? 10w at full output is enough to wake the house (unless it's a rilly big house )

 

if i get this right <"if" alert!>, the 3dB figure applies to the diff between 10w & 20w...i.e., a 20w amp will be about 3dB louder than a 10w. a 100w (10x the output) will be 2x as loud but with a lot more dBs, but i forget how many, cuz it's outa my depth. certainly enough to drown out the 10w amp, whereas the 20w amp would dominate but not overwhelm the 10w.

[mars_hall]

what were the volume settings & actual output? 10w at full output is enough to wake the house (unless it's a rilly big house )

 

if i get this right <"if" alert!>, the 3dB figure applies to the diff between 10w & 20w...i.e., a 20w amp will be about 3dB louder than a 10w. a 100w (10x the output) will be 2x as loud but with a lot more dBs, but i forget how many, cuz it's outa my depth. certainly enough to drown out the 10w amp, whereas the 20w amp would dominate but not overwhelm the 10w.

 

Remember we are dealing with logarithmic numbers (exponent/powers of a base number) and not the linear numbers with which we are normally familiar. Also remember that dB is a ratio of two numbers, typically power or voltage where output is compared over input

[rjsanders]

...

 

In other words, this amp will produce 89db at 1 watt. Using the doubling method: 91db = 2 watts, 94db = 4 watts, 98db = 8 watts, 101db = 16watts, 104db = 32 watts, 107db = 64watts, 111db = 128watts. So in this example, the amp will achieve a little over 107db w/3db headroom means up to 111db basically.

 

yeahman. what he said.

 

'far as relative loudness goes (when comparing with other configs, e.g.) speaker efficiency is a big factor, too. so that at full output a 10w amp into a 100dB-efficient speaker (e.g., Celestion Gold) would keep up nicely with a 20w amp into a 97dB speaker (say, a Jensen Blackbird)

[rjsanders]

Remember we are dealing with logarithmic numbers (exponent/powers of a base number) and not the linear numbers with which we are normally familiar. Also remember that dB is a ratio of two numbers, typically power or voltage where output is compared over input

 

yeahman. what he said.

 

here's a useful article on loudness in dB

[JeffB]

Ok...Just to clear up...its about the "3dB" more than 10 v 100w really. Its about volume not watts.

I laid out the parameters of how I went about it. I used the 10w/100w switch instead of turning dials to cut/boost power and volume. It was just quicker.

In every amp discussion about watts everyone wheels out the stats, 50w is only 3dB quieter than 100 dB, takes 10 jet engines to be twice as loud as one etc. On the gear page alone there is 5332(give or take a few) threads about small amp v big amps. Stats and formulas up the wazoo and not one attempt at a clip to try and show what 3dB sounds like. It sounds great.

The difference between the wattage selections at the volume I was playing at was 3db. Its just that simple.

Now if you are listening through a lap top's speakers it wont be 3dB difference but you will still hear the volume difference. What doesnt really alter is the sound except for the Fletcher Munson effect. If you crank it through your mega 2000w home entertainment system at full volume the difference wont be 3dB but you will hear the difference 3dB makes on the original recording.

[mars_hall]

It is important to not confuse apples for oranges and remember dB is a number derived from a ratio of an output over its input which is then multiplied by a number, depending on what characteristic is being compared.

 

The input and output can be different characteristics among which are voltage, power, or in the case of speakers, SPL (sound pressure level) which is a measure used in acoustic power measurements.

 

Likewise, microphones are rated having a sensitivity which is measured in dBs or dBm (1/1000th dB), but using different characteristics (millivolts).

 

Typically a speaker's SPL is measured at 1 meter distance with a sine wave input of 1 kHz using a 1 watt input, This allows standard comparisons to be made with other speakers.

 

The point of all this is that dB can easily be misused and/or misconstrued in general conversation if you are not careful about what you are comparing.

[NoNameBand]

yeahman. what he said.

 

'far as relative loudness goes (when comparing with other configs, e.g.) speaker efficiency is a big factor, too. so that at full output a 10w amp into a 100dB-efficient speaker (e.g., Celestion Gold) would keep up nicely with a 20w amp into a 97dB speaker (say, a Jensen Blackbird)

 

This is where you look at the nominal rating ie; 89db @ 1watt. This is the "input sensitivity". So if you know how loud (?db) a speaker/amp is at 1 watt, you can figure out how loud it will be at any other wattage. However, just because you turn your Fender Twin Reverb (100 watt version) up to 10 on the volume, this doesn't mean you are using 100 watts. This gets in to Dynamic range. If the Volume knob is on 5 and you play soft, you might be using 10 watts and simply by playing harder, using 100 watts while the volume knob was unchanged. This is called "Headroom" (not the bathroom). This is what gives you the ability to express your touch/dynamics on the guitar and what Fender amps do so well. They have a Ton of headroom. Most Tube amps do.

 

The more efficient the speaker is (rated at 1 watt), the louder your amp will be with the amount of power you have available. However, the more efficient a speaker is, the sloppier it is. In other words, they take less power to move in/out. Fast, tight, crisp sound are not characteristics of an efficient speaker, example GK 10" bass cab speakers are NOT efficient. A 12" Jensen from the old Fender 5E3 Tweed series rated at 15 - 20 watts are the epitome of efficient, but can be noisy and sloppy.

I hope this diatribe helps.

Over and out

[mars_hall]

This is where you look at the nominal rating ie; 89db @ 1watt. This is the "input sensitivity". So if you know how loud (?db) a speaker/amp is at 1 watt, you can figure out how loud it will be at any other wattage. However, just because you turn your Fender Twin Reverb (100 watt version) up to 10 on the volume, this doesn't mean you are using 100 watts. This gets in to Dynamic range. If the Volume knob is on 5 and you play soft, you might be using 10 watts and simply by playing harder, using 100 watts while the volume knob was unchanged. This is called "Headroom" (not the bathroom). This is what gives you the ability to express your touch/dynamics on the guitar and what Fender amps do so well. They have a Ton of headroom. Most Tube amps do.

 

The more efficient the speaker is (rated at 1 watt), the louder your amp will be with the amount of power you have available. However, the more efficient a speaker is, the sloppier it is. In other words, they take less power to move in/out. Fast, tight, crisp sound are not characteristics of an efficient speaker, example GK 10" bass cab speakers are NOT efficient. A 12" Jensen from the old Fender 5E3 Tweed series rated at 15 - 20 watts are the epitome of efficient, but can be noisy and sloppy.

I hope this diatribe helps.

Over and out

 

Not sure I agree with your last paragraph in the analogy for sloppiness and believe the exact opposite. EVM-12S are among the most efficient speakers made, more efficient the the 12L, and they could never be classified as sloppy, quite the opposite. Don't mean to contradict your post here...

[NoNameBand]

Not sure I agree with your last paragraph in the analogy for sloppiness and believe the exact opposite. EVM-12S are among the most efficient speakers made, more efficient the the 12L, and they could never be classified as sloppy, quite the opposite. Don't mean to contradict your post here...

 

The term efficient is an ambiguous term. Depending on how efficient a speaker is. I'm not saying all efficient speakers are sloppy. Just that the easier it is to move a speaker or the less energy it takes to move a speaker in/out the sloppier it gets. I think I gave an accurate comparison of the GK 10" bass speaker compared to a 12" Jensen Tweed speaker or even the original 10" Fender Bassman speaker. The less efficient a speaker is, the Tighter it is and the more accurate it is in the reproduction of sound. The bigger the magnet, the less efficient it is, the faster it moves back and is ready to come forward again. The more efficient a speaker is, the less power it needs to move, the easier it extends forward and the slower it returns back in place to extend again. This is noticed more in lower frequencies as this is what tends to extend the range of a speaker.

[rjsanders]

Ok...Just to clear up...its about the "3dB" more than 10 v 100w really. Its about volume not watts.

I laid out the parameters of how I went about it. I used the 10w/100w switch instead of turning dials to cut/boost power and volume. It was just quicker.

...

 

"sounds" like you mean sound pressure level or loudness. the dB's a real versatile unit of measure and has lotsa applications, leading to lotsa debates which are really just a buncha folks trying to define their terms & applications (even optics).

 

so, you're using the same amp with same speakers at the same tone & volume settings and hearing a difference (in dB SPL) when an output switch is flipped between 10w & 100w. the difference will be more or less than 3dB depending on how hard you hit the strings (more noticeable over a wider range of frequencies on the rock riff - nicely done, btw) and which frequencies you hear from 20-whateverKHz.

 

i hear more content (lower & higher freqs) in the 100w setting than 10w using a Mac plugged into external power speakers w/subwoofer & i'm running that at about 1/4 power (i think - 1/2 volume on Mac, 1/2 volume on powered speakers).

[Steiner]

The term efficient is an ambiguous term. Depending on how efficient a speaker is. I'm not saying all efficient speakers are sloppy. Just that the easier it is to move a speaker or the less energy it takes to move a speaker in/out the sloppier it gets. I think I gave an accurate comparison of the GK 10" bass speaker compared to a 12" Jensen Tweed speaker or even the original 10" Fender Bassman speaker. The less efficient a speaker is, the Tighter it is and the more accurate it is in the reproduction of sound. The bigger the magnet, the less efficient it is, the faster it moves back and is ready to come forward again. The more efficient a speaker is, the less power it needs to move, the easier it extends forward and the slower it returns back in place to extend again. This is noticed more in lower frequencies as this is what tends to extend the range of a speaker.

 

 

Efficiency is a very precise, scientific term and devoid of ambiguity. The ambiguity begins when one uses "tends".

[212Mavguy]

There are variables affecting efficiency of a speaker, VC construction, gap between VC and magnets, spider stiffness, heaviness of cone paper, shape and stiffness of cone as well as surround to name a few.

 

True woofers have a larger gap between the VC and the magnets, it's there to reduce high frequency output. They are also less efficient as a rule for the same reason. Fullrange speakers as a rule have tighter VC gaps.

 

My Altec Lansing ER-12s predates the EV 12s, and it is very efficient as well as incredibly articulate at "hearing damage" sound pressure levels. Same with my 12 and 15 inch JBL g125's and 135's. Sloppy? Not. The VC design these speakers use with flattened ribbon wire and their magnetic field design deliver both efficiency and precision in output, even with 50 watt amps dimed through them. I don't have any 100 watt amps, but these speakers are designed to and can individually handle 100 watts all day.

[big bob]

what? ... Dude , look ... shrimp!

[JeffB]

"sounds" like you mean sound pressure level or loudness. the dB's a real versatile unit of measure and has lotsa applications, leading to lotsa debates which are really just a buncha folks trying to define their terms & applications (even optics).

 

so, you're using the same amp with same speakers at the same tone & volume settings and hearing a difference (in dB SPL) when an output switch is flipped between 10w & 100w. the difference will be more or less than 3dB depending on how hard you hit the strings (more noticeable over a wider range of frequencies on the rock riff - nicely done, btw) and which frequencies you hear from 20-whateverKHz.

 

i hear more content (lower & higher freqs) in the 100w setting than 10w using a Mac plugged into external power speakers w/subwoofer & i'm running that at about 1/4 power (i think - 1/2 volume on Mac, 1/2 volume on powered speakers).

I think that is what I meant as it turns out after reading some of the other posts. I think you summed up what I was on about. Thanks.

[bolero]

interesting!!

 

the first time I've actually seen someone try to demonstrate, rather than regurgitating the common internet phrases

 

isn't 1dB the minimal change an ear can percieve? so it's 3 of those minimal perceptions, you get, if you double the wattage?

 

however this has to be different for everyone?

 

ie: I think one Pete Townshend dB is different than Sister Suzie, brother John,

Martin Luther, Phil And Don, Brother Michael, and Auntie Gin's dB

[blackjack]

Here it all is in one place, from a decent reference. I posted it just in case you're like me and always forget that SPL and perception of loudness are different. If so, skip right to the last 2 definitions. Very knowledgeable group, really impressive.

 

 

What is a Decibel (dB)?

A dB or Decibel is a logarithmic unit of measure of the ratio between two numbers.

 

dB and Power (20dB = 100x)

When talking about power, 3dB represents a ratio of two to one or a doubling of power.

•Thus, a gain of 10dB would represent a ratio of ten to one for power - so 10 dB be 10 times the power

•A 40dB power gain would be 10,000 times the power.

 

dB and Voltage gain (20dB = 10x)

When talking about voltage, 6dB represents a ratio of two to one or a doubling of voltage.

•20dB would represent a ratio of ten to one for voltage - so 20 dB would be 10 times the voltage.

•A 40dB voltage gain would be 100 times the voltage.

 

dB SPL (Sound Pressure Level) (20dB = 10x)

The term “SPL” stands for sound pressure level. SPL measures are taken with respect to the minimum threshold for human hearing. A 20 dB difference in SPL represents a ratio of ten-to-one in sound pressure.

•Thus, a 40dB SPL would be a sound pressure level that is 100 times greater than the sound pressure level of the quietest sound that normal human hearing can detect.

 

Perception of Loudness (20dB = 4x)

Interestingly, our perception of loudness is not the same as sound pressure level. Although the actual formulae

is somewhat complex, as a rough rule of thumb, an increase of 10db SPL is perceived to be approximately twice as loud.

•Thus a 20 Db gain would seem to be about 4 times as loud.

•And a 40 Db gain would seem to be about 16 times as loud.

[JeffB]

interesting!!

 

the first time I've actually seen someone try to demonstrate, rather than regurgitating the common internet phrases

 

isn't 1dB the minimal change an ear can percieve? so it's 3 of those minimal perceptions, you get, if you double the wattage?

however this has to be different for everyone?

 

ie: I think one Pete Townshend dB is different than Sister Suzie, brother John,

Martin Luther, Phil And Don, Brother Michael, and Auntie Gin's dB

Thanks for understanding what I was aiming at.

 

To be fair even though I was using a 100w amp it was at a volume where 1w would have done the job just as easy. Honestly could have been 1/2 a watt or less.

I read this somewhere

A typical guitar speaker will produce about 95 to 100dB at 1 meter (about 3.3ft) with 1 watt of input power

So whether I used 100w or 1 watt at the very low volume I was playing at is not important other than I guess, to show you can use a 100w amp through 120w speaker cab at way quieter levels than a cranked 1w amp. Whether its a sound you like or not is a whole other can of worms.

[tulk1]

Tully, thanks for doing the clip. I'm going to listen again over the multi-mega watt home unit tonite, rather than the laptop and crappy headphones like I just did. Personally I don't care what the math is that gets us there. What I care about are the end results. I grew up in the "bigger is better" era. Years ago I gave up the 100watters in favor of less wattage, more portability. First thing I noticed is less fullness. Not volume, but fullness. I love my tweeds, Dr. Z and Voxes and man, they can get loud. But in all, they are not as full to my ears as the Mesa LS (original, #450 S/N ... ahem!!) on 100w at the same "perceived" volume. Nothing mathematical involved, nothing scientific about my experience. Just that ... personal experience.

 

NYE we had a fiddle player come up from Branson (uh, Nashville, Jr. in these parts). Small man, monster player. And what did this guy drag up on stage? A friggin' Fender Twin Reverb!! Played on 3.5. Just like I did way back when. And talk about warm and full. Wow. Miss that. Uh, don't miss the weight! Not at all. But that tone ... and warmth. Too bad I can no longer run with the big dog amps live.

[NoNameBand]

Efficiency is a very precise, scientific term and devoid of ambiguity. The ambiguity begins when one uses "tends".

 

Maybe I should have said relative term based on what you are comparing it to. For example, in the 70's we had 8 track car stereos with 3 watts and they were plenty loud. Now we have 1,000 watt car stereos and though they are louder, they are more accurate in their reproduction of sound. The same holds true for all speakers. This means, the less efficient a speaker is, the more accurate it is. The best home/pro audio speakers today are not as efficient as the older ones though they are more accurate and have better frequency response across the spectrum. This can be easily confirmed by Electro-Voice or JBL.

[rjsanders]

... This means, the less efficient a speaker is, the more accurate it is. The best home/pro audio speakers today are not as efficient as the older ones though they are more accurate and have better frequency response across the spectrum. This can be easily confirmed by Electro-Voice or JBL.

 

 

hmmm, i think i gotta disagree here, tho' not sure about modern audio systems. back in the day, i recall, i liked Bose 901s and JBL L100s. the former were relatively inefficient, the latter more efficient. but i leaned toward the JBLs. my all-time faves for accuracy (strictly subjective) were unusually efficient, 105dB, tho' i didn't know that at the time. efficiency is just one of many variables in speaker design. and then there's the additional complexities in speaker enclosure, etc.

 

[rjsanders]

Here it all is in one place, from a decent reference. I posted it just in case you're like me and always forget that SPL and perception of loudness are different. If so, skip right to the last 2 definitions. Very knowledgeable group, really impressive.

 

 

What is a Decibel (dB)?

A dB or Decibel is a logarithmic unit of measure of the ratio between two numbers.

...

 

xlnt. what's the source?

[rjsanders]

xlnt. what's the source?

 

 

found it...http://trace.wisc.edu/docs/2004-About-dB/