What really makes a Amp loud?

[dystrust]

Re: What really makes a Amp loud?

Tubes.. Tubes also go a long way in the quest for loudness.
You want real loud get a Mesa Boogie Coliseum it's 200 watts of pure tube power and it's the loudest damn thing I've ever plugged into. 2 4x12s and I thought the dudes house was gonna cave in.
It hurt, I never wanna play one again.
You want loud you can't beat 100 tube watts thru a 4x12 or a Fender Twin, they are also crazy loud.
I have owned a 200 watt Randall for a metal band but it was nothing compared to my Marshall JCM 900 100 watt. You can't beat tubes for loudness.

Tubes have nothing to do with volume; watts are watts, end of story. A solid state amp producing the same wattage into the same cabinets would be equally loud. Your Randall was probably 200W @ 4 ohms which would work out to 50W into a typical 16 ohm Marshall 4x12.

^AC30s are also extremely loud. The thing with tube amps is that we like to push the power section into overdrive, and most of the time a dimed amp is cranking out more wattage than what it is rated as (which is RMS). The peak wattage is higher, and different amps will go different lengths beyond their RMS wattage. An AC30's peak wattage when dimed is significantly over 30 watts, combined with the fact that it is a midrange-dominant amp, which makes for one really loud amp.

Myaccount got it right, but there's more to it that than. IMO the most important factor in why tube amps seem louder is the tube amp's output transformer. This ensures that the tube amp produces full power into any matching load. SS amps OTOH only produce full power into their rated load, and that power is cut in half if the load doubles. For example a SS amp rated for 300W into 4 ohms only produces 150W into 8 ohms and 75W into 16 ohms.

I ran into a real world example of this during a craigslist deal earlier this year. I was buying an Ampeg SVT-3 Pro from someone who'd recently switched to an SVT Classic, and he couldn't understand why the 3 Pro was louder. The SVT Classic has a tube power section with OT, so it produces around 300W into 8, 4, or 2 ohms, while the 3 Pro is rated 275W @ 8 ohms and 450W @ 4 ohms. He was using a 4 ohm Ampeg 8x10, so it shouldn't be a huge surprise that 450W was louder than 300W.

 

[IM4Tone]

Re: What really makes a Amp loud?

Wrong. All things being equal, doubling the number of speakers in a rig will give you 3dB more volume. So go from one to two=3 dB. Go from two to four = another 3dB. Go from four to eight = yet another 3dB. That makes a 9dB difference which is as close enough for rock-n-roll twice the volume. That's why a full stack at full chat will smoke the same amp into one speaker.

You are definitely mistaken. That would be a violation of the law of physics...'Conservation of Energy'
Take one speaker powered by 50 watts and compare the SPL to two speakers (identical to the first in sensitivity/efficiency) powered by 50 watts total. SPL will be identical. To achieve the 3db increase, EACH of the two speakers must have 50 watts of power applied, or twice as large (in power output) amp.

Think about it....if what you stated was correct, all one would have to do would be to add more and more and more speakers and eventually you could achieve 120 db (for discussion purposes) with only 1 watt of power. Keep going and you could....well, you get the idea.

 

[GoldenVulture]

Re: What really makes a Amp loud?

You are definitely mistaken. That would be a violation of the law of physics...'Conservation of Energy'
Take one speaker powered by 50 watts and compare the SPL to two speakers (identical to the first in sensitivity/efficiency) powered by 50 watts total. SPL will be identical. To achieve the 3db increase, EACH of the two speakers must have 50 watts of power applied, or twice as large (in power output) amp.

Think about it....if what you stated was correct, all one would have to do would be to add more and more and more speakers and eventually you could achieve 120 db (for discussion purposes) with only 1 watt of power. Keep going and you could....well, you get the idea.

Your going against the conventional wisdom of sound/audio engineering. Research it, I think you'll find you are wrong.

 

[allbutromeo]

Re: What really makes a Amp loud?

I'm curious about the answer on number of speakers. Is it really louder with more, or is it a perceived increase in volume due to a wider disbursement of sound compared to a more directionally focused projection from a single speaker?

 

[IM4Tone]

Re: What really makes a Amp loud?

Wrong. All things being equal, doubling the number of speakers in a rig will give you 3dB more volume. So go from one to two=3 dB. Go from two to four = another 3dB. Go from four to eight = yet another 3dB. That makes a 9dB difference which is as close enough for rock-n-roll twice the volume. That's why a full stack at full chat will smoke the same amp into one speaker.

Your going against the conventional wisdom of sound/audio engineering. Research it, I think you'll find you are wrong.

Laws of physics are not wrong. They've endured forever. I will guarantee this to be correct.
The speaker is a device that converts electrical energy into sound waves, both of which can be measured (electrical in watts; sound wave energy/SPL in db). When energy is converted from one form to another, the best that can happen idealistically is the conversion is 100%. It cannot result in more energy when transformed. At a specified efficiency (or sensitivity) the 50 watts in the example will be subdivided between the two speakers and the total SPL out will be the same db. Only by applying 50 watts to each speaker will the resultant SPL increase by 3 db.

 

[IM4Tone]

Re: What really makes a Amp loud?

I'm curious about the answer on number of speakers. Is it really louder with more, or is it a perceived increase in volume due to a wider disbursement of sound compared to a more directionally focused projection from a single speaker?

Yes, there is often the perception of volume increase due to the wider dispersion. Measurement with an SPL meter will show such is not truly the case.

 

[Guitaraxz]

Re: What really makes a Amp loud?

the 50w through the 4x12 will probably be louder.

volume is determined by output from the amp and efficiency of the speaker/s involved. with the same amp, a single 10" could be louder than a 2x12 if it was efficient enough.

a 20w amp with a speaker rated at 103dB will be louder than a 100w amp with a speaker rated at 95dB

Yes!

 

[DrNewcenstein]

Re: What really makes a Amp loud?

The "Laws" of physics are, at best, suggestions, not "you're going to jail Laws". As these "Laws" were agreed upon by those who agree upon such things as being the most reasonable explanations, they were called "Laws". However, as I've said, these are not the same as real-life Laws such as govern taxation and other crimes, so do not represent them as absolutes.


My singer and I had the same head - Fender RocPro 1000. I ran mine into a Carvin 2x12 cabinet. He ran his into a TubeWorks 4x12. His was barely audible compared to mine. We swapped rigs to see if it was guitar or player related, and it wasn't. His closed-back 4x12 was not moving as much air as my open-back 2x12.

 

[Edgecrusher]

Re: What really makes a Amp loud?

The "Laws" of physics are, at best, suggestions,

You've made some stupid statements before.... But this takes the taco.

 

[Securb]

Re: What really makes a Amp loud?

Wanna make an amp loud? Add a few of these. Your playing gets better also.

 

[Progbusters]

Re: What really makes a Amp loud?

One amp and cab was used, two speakers were miked into the PA.. The PA and the perception of having two stacks mad it loud, haha. Oh btw this is Loudness
https://twitter.com/progbusters/status/658419472890400768

 

[IMENATOR]

Re: What really makes a Amp loud?

You've made some stupid statements before.... But this takes the taco.

I like the suggestions by Newton, Gauss, Kirchoff, Testla, Einstein and all those master minds.

 

[GoldenVulture]

Re: What really makes a Amp loud?

Laws of physics are not wrong. They've endured forever. I will guarantee this to be correct.
The speaker is a device that converts electrical energy into sound waves, both of which can be measured (electrical in watts; sound wave energy/SPL in db). When energy is converted from one form to another, the best that can happen idealistically is the conversion is 100%. It cannot result in more energy when transformed. At a specified efficiency (or sensitivity) the 50 watts in the example will be subdivided between the two speakers and the total SPL out will be the same db. Only by applying 50 watts to each speaker will the resultant SPL increase by 3 db.

The Maths must be broken then.

100 watts x 1 12" speaker Vs 4 X 12" speakers.


- http://www.rapidtables.com/convert/power/Watt_to_dBm.htm -

100 watts = 50 Db.

Divided by four equals 25 watts

25 watts = 43.0794 Db

43.0794 + 3 + 3 + 3 = 52.0794.

-------------------------------------------------

50 Watts X 1 12 " speaker Vs 4 x 12" speaker

50 watts =46.9897 Db

divided by four equals 12.5 Watts

12.5 watts = 40.9691

40.9691 +3 +3 +3 = 49.9691

 

[IM4Tone]

Re: What really makes a Amp loud?

The Maths must be broken then.

How about: 43.979* +3 +3 = 49.979; Doubling the initial speaker from 1 to 2 gives 43.979 +3= 46.979 Then doubling the 2 speakers to 4 yields 46.979 +3 = 49.979 Note that this relationship is logarithmic, NOT linear.
Ahh...math ain't broken!
*Re-check your calculator.
Example 2:
40.9691 +3 +3 =46.9691 Again, double to two speakers, then double to four speakers.

 

[GoldenVulture]

Re: What really makes a Amp loud?

How about: 43.979* +3 +3 = 49.979; Doubling the initial speaker from 1 to 2 gives 43.979 +3= 46.979 Then doubling the 2 speakers to 4 yields 46.979 +3 = 49.979 Note that this relationship is logarithmic, NOT linear.
Ahh...math ain't broken!
*Re-check your calculator.
Example 2:
40.9691 +3 +3 =46.9691 Again, double to two speakers, then double to four speakers.

[* - I copied the number wrongly, I corrected it. The result number was corrected.]

This gives an even greater disparity in favour of 4 x 12.
- http://www.engineeringtoolbox.com/adding-decibel-d_63.html -
Adding Equal Sound Pressure Levels Calculator

 

[IM4Tone]

Re: What really makes a Amp loud?

[* - I copied the number wrongly, I corrected it. The result number was corrected.]

This gives an even greater disparity in favour of 4 x 12.
- http://www.engineeringtoolbox.com/adding-decibel-d_63.html -
Adding Equal Sound Pressure Levels Calculator

Sorry, I'm not following/understanding????? Please clarify.
Did you follow that the increase of 3 db occurs when the number of identical sources is doubled? i.e. the progression is 1,2,4,8,16. This is verified by the chart in your second link. Note when x=2, y=3; x=4, y=6; x=8, y=9

 

[GoldenVulture]

Re: What really makes a Amp loud?

Sorry, I'm not following/understanding????? Please clarify.
Did you follow that the increase of 3 db occurs when the number of identical sources is doubled? i.e. the progression is 1,2,4,8,16. This is verified by the chart in your second link. Note when x=2, y=3; x=4, y=6; x=8, y=9

yes, I've known this for over thirty years.
I was reffering to the following. [ Different calculator ]
Adding Equal Sound Pressure Levels Calculator

Adding Equal Sound Pressure Levels Calculator

25 watts

L[SUB]ps[/SUB] - 43.0794 - sound pressure level (dB)

n - 4 - number of sources

Sound Pressure Level (dB) : 55.1
​

 

[DrNewcenstein]

Re: What really makes a Amp loud?

You've made some stupid statements before.... But this takes the taco.

So puny mortals unlocked the secrets of the universe and declared their findings to be universal, unquestionable, and therefore "Laws"? Oh, the hubris of Man!

Have some more kool-aid, chief.

 

[Demanic]

Re: What really makes a Amp loud?

^^
The Laws exist. As to whether or not they are yet fully understood is another story. Yet you can not deny that progress in understanding them has been made. The means of our discussion of the subject are proof of that. I am willing to bet that if you took your guitar and amp across the galaxy, into a similar environment as to which they now occupy, and played them, everything would still function as it does now, barring any damage incurred during transport.

 

[DrNewcenstein]

Re: What really makes a Amp loud?

I concede that they are solid concepts, principles and valid arguments, but in no wise will I concede that such an immature species has the collective intelligence to declare those principles "Laws", as if to suggest no other possibility. Especially given the fact that many of these pre-date indoor plumbing.