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View Full Version : Is a 4x12 louder than a 2x12?


mooch
02-14-2007, 01:57 PM
Seems like a silly question. I would think that the same amp at the same volume setting through a 4x12 versus a 2x12 would be the same volume, but the 4x12 would move more air and seem fuller, but not necessarily louder. Do you find this to be true?

rockon1
02-14-2007, 02:04 PM
I dont care what anybody says! I say yes.( Was a long debate about this on another board recently.) In my small music room my ears always pay the price when I hook up to my 4x12 as compared to my 2x12 with the same amp.

JamesHealey
02-14-2007, 02:14 PM
Deffinatly louder I was running a 2x12 and then a 4x12 the otherday A/Bing them and it's deffinatly louder, pushes more air and has more bass response.. can be a bit overwhelming at times.

CocoTone
02-14-2007, 02:19 PM
Your kiddin` right??:confused:

CT.

gtrfinder
02-14-2007, 02:35 PM
I dont care what anybody says! I say yes.( Was a long debate about this on another board recently.) In my small music room my ears always pay the price when I hook up to my 4x12 as compared to my 2x12 with the same amp.

Perhaps that is because the top 2 speakers are closer to your head in a 4x12?

enharmonic
02-14-2007, 02:39 PM
I say no, but you can feel a 4x12 a lot easier than a 2x12.

electronpirate
02-14-2007, 02:42 PM
Sometimes.

Depends on the 4x12. My Mesa vertical 2x12 knocks the socks off of alot of 4x12's.

HOWEVER. I still agree that in general a 4x12 has more 'fullness' and girth for lack of better words. Thump maybe.

EP

DejavuDave
02-14-2007, 03:22 PM
The perception is that it is louder because the source and dispersion are greater. You will hear yourself better with a 4x12 over a 2x12 in most live scenarios.

zdogma
02-14-2007, 03:28 PM
I've had this discussion a few times with a variety of "experts" and no one seems to agree.

Here's an article that seems to make sense:

http://www.musiccenters.com/vol.html

rwe333
02-14-2007, 03:33 PM
Must admit I find most 4x12 poorly designed - don't project, etc. Sound good on their own, get lost in a band.
So, I often find a well designed 2x12 or even 1x12 throws better and sounds louder.
There are exceptions like the incredible old Hiwatt 4x12, the current THD 4x12, etc...

TYY
02-14-2007, 03:34 PM
Yes of course. It's 24" louder. Simple math.

epluribus
02-14-2007, 04:16 PM
Seriously, in addition to the question at hand, what if the choice is between a 4X12 and 4 1X12s? ...or 2X12 vs. 2 1X12s? Presuming same speakers, same type cabs.

--Ray

coreybox
02-14-2007, 05:14 PM
anyone have db meter handy?

DiazDude
02-14-2007, 06:07 PM
I've got a 4x12 Marshall TVB & a Soldano 2x12. Same Celestion G12H's in both. A/B with my Diaz CD100 the 4x12 is louder to my ear. Not by alot mind you. Thicker voice in the 4x12 as well.
Ears don't lie!!

cameron
02-14-2007, 08:11 PM
Seems like a silly question. I would think that the same amp at the same volume setting through a 4x12 versus a 2x12 would be the same volume, but the 4x12 would move more air and seem fuller, but not necessarily louder. Do you find this to be true?

Depends.

The efficiency of the speakers in question will make a huge difference. More efficient speakers in a 2x12 will very likely be quite a bit louder than relatively quiet speakers in a 4x12.

Even assuming that the speakers are the same efficiency throughout, the 2x12 might still be louder. With a 4x12 you're getting half as much power to each speaker as with a 2x12. In some cases the difference in power supplied to the speaker might be enough to overcome the difference in perceived volume due to the extra speaker surface area from the 4x12.

It is true that the apparent volume to the player might be influenced by the height of the 4x12 cabinet. Often people put a 2x12 on its side and aim it at their knees. Put the 2x12 on its end.

malabarmusic
02-14-2007, 10:11 PM
Assuming all 4 speakers have the same efficiency rating and holding constant cabinet design, a 4x12 will be 3dB louder than a 2x12. No more, no less.

- DB

cameron
02-14-2007, 11:49 PM
Assuming all 4 speakers have the same efficiency rating and holding constant cabinet design, a 4x12 will be 3dB louder than a 2x12. No more, no less.

- DB

No. If all six speakers have the same efficiency, each individual speaker in the 2x12 will be 3dB louder than each individual speaker in the 4x12. But the fact that there are 4 speakers in the 4x12 will counteract that difference.

With the same wattage, sometimes the 2x12 will sound louder, sometimes the 4x12. It depends on the speakers, and how they respond.

rcgpny1
02-15-2007, 12:09 AM
Some of you are forgetting a very important aspect. If we are talking tube amps with variable output impedance, then the output taps sound different. The 16 ohm tap uses all of the windings whereas the 8 and 4 ohm taps are using the appropriate fraction of them.
I always thought there was something about a single 4x12 that was better than a stack. More focused and a better low end...not more...but better rounder fuller. That was because at 16 ohms we're using all of the windings.Also unless we know the sensitivity rating of the speakers we cant really be sure where the differences we hear are comming from. A greenback has a sens. of 98db. The vintage 30 is 101. You have to give the greenback more than twice the amount of power in for the same output......just a though R

GCDEF
02-15-2007, 09:00 AM
Assuming all 4 speakers have the same efficiency rating and holding constant cabinet design, a 4x12 will be 3dB louder than a 2x12. No more, no less.

- DB

Not true at all. Would 8 speakers then be 6 dB louder. 16 would be 9 dB. With enough speakers you could plug into a clock radio and play a stadium. Carry that theory to its logical conclusion and you can see it makes no sense at all.

A 4 x 12 with the same speakers can be louder especially as you increase the volume. Typically speakers become less efficient the closer they get to their maximum output. So if you're not pushing your 2 x 12 too hard, a 4 x 12 won't make any difference. If you're already pushing your 2 x 12 close to its max SPL, a 4 x 12 may give you a bit more volume.

The thing to keep in mind here is power comes from the amplifier. Adding passive devices (speakers) doesn't add power. The only way to increase volume without increasing power is to convert the amp's electrical energy to acoustic energy more efficiently. Using enough speakers so that they operate in the power range where they're most efficient will maximize your volume. Whether a 4 x 12 will be louder depends on how efficiently your 2 x 12 is operating when you start.

bluesmain
02-15-2007, 09:04 AM
move more air for sure but I don't know about volume depends on the speakers and the amp

cliffc8488
02-15-2007, 09:14 AM
Watts is watts. If you put 5 watts into either cabinet you'll get the same acoustic power out (ignoring losses). Ignoring efficiency (losses) then you'll get 5 watts of acoustic power out.

However, the 4x12 will sound louder because it has a higher D.I. (directivity index). What this means is that the power from the 4x12 is "focused", or less dispersed than a 2x12. So if you are standing in front of a 4x12 it will sound louder than if you are standing in front of a 2x12 (assuming you're in the far-field, which you likely will be).

I believe (off the top of my head, no calculations) that the increased D.I. will make the 4x12 3dB louder.

CC

Austinrocks
02-15-2007, 11:44 AM
Sound Pressure Level of a speaker is determined by its efficiency and the power from the amp,

dB-SPL/watt at 1 meter is how their efficiency used to be stated, it is now a sensitivy of dB-SPL for 2.83 volts at 1 meter. However the idea is the same a speaker will produce a SPL for 1 watt at 1 meter.

A 100 dB-SPL/watt at 1 meter speaker will produce 100 dB-SPL at 1 meter when 1 watt is input into the speaker.

a 100 watt amp is 20 dBW it will produce a 120 dB SPL at 1 meter with a speaker that is 100 dB-SPL/ watt at 1 meter, the speaker is operating at 100 watts.


Two of those speakers will produce 120 dB-SPL at 1 meter with a 100 watt amp, the power is divided between the two speakers, each speaker producing 117 dB-SPL at 1 meter.


100 of those speakers will produce 120 dB-SPL at 1 meter with a 100 watt amp, the power is divided between the 100 speakers, each speaker operating at 1 watt, each speaker producing 100 dB-SPL at 1 meter

10,000 of those speakers will produce 120 dB-SPL at at 1 meter with a 100 watt amp, the power divided between the 10000 speakers, each speaker operating at .01 watt, each speaker producing 80 dB-SPL at 1 meter.

More speakers does not make you louder, your not pushing more air, you are dividing the power between more speakers, which will allow you operate with more power.

the 100 dB-SPL rated for 100 watts operating power,

1 speaker will produce 120 dB-SPL at 1 meter when operated with 100 watts

100 speakers will produce 140 dB-SPL at 1 meter when operated with 10,000 watts

10000 speakers will produce 160 dB-SPL at 1 meter when operated with 1,000,000 watts

The more speakers let you use a larger amplifier which will produce a higher SPL level.

Using the same amp more speakers will not produce a higher SPL if more speakers are added.

Austinrocks
02-15-2007, 11:46 AM
More speakers mean you can handle more power, the same power amp will produce the amount of sound as long as the speakers can handle the power, more speakers and same power will produce the same SPL.

Austinrocks
02-15-2007, 11:48 AM
The speaker sensitivity term determines how much Sound Pressure Level a speaker produces for watt of power from an amp,

three common Celestion Speakers, greenbacks are classic marshall speakers, the G12T-75 is used in the Marshall 1960 cabinet, the Vintage 30s are used in the Mesa Rectifier Cabinets. I have Vintage 30s in my Marshall 1960 cabinet, it came with greenbacks, so am pretty familiar with both those speakers.

http://professional.celestion.com/guitar/products/classic/spec.asp?ID=5 (http://professional.celestion.com/guitar/products/classic/spec.asp?ID=5)
http://professional.celestion.com/guitar/products/classic/spec.asp?ID=6 (http://professional.celestion.com/guitar/products/classic/spec.asp?ID=6)
http://professional.celestion.com/guitar/products/classic/spec.asp?ID=4 (http://professional.celestion.com/guitar/products/classic/spec.asp?ID=4)


Greenback sensitivity of 98dB, 25 watt power handling
G12T-75 sensitivity of 97dB, 75 watt power handling
Vintage 30 sensitivity of 100dB, 60 watt power handling

for the same amp power, say 100 watts,

A cabinet with G12T-75 needs twice the power to be as loud as a Vintage 30

Same SPL will come from the following combinations of amp and speaker

100 watts with a G12T-75
63 watts with a GreenBack
50 watts with a Vintage 30

You will see that you need a different number of speakers to handle the power, more speakers does not make you louder, they let you handle more power.

for a 100 watt amp, two G12T-75 are required, two Vintage 30s are required, and four Greenbacks, though I found that I blew the green backs with only one cabinet, so I had to use a full stack when I was playing my 100 marshall head

Miles
02-15-2007, 11:49 AM
I dont care what anybody says! I say yes.( Was a long debate about this on another board recently.) In my small music room my ears always pay the price when I hook up to my 4x12 as compared to my 2x12 with the same amp.

If you're 4x12 is a slant and the top speakers are aimed at your head, that would explain it. Not louder, but harsher.

JP
02-15-2007, 11:51 AM
BY adding additional speakers, you see a 3DB increase per speaker, so a total of 6 DBfor a 4x12. To further add the sonic quality, you are dealing with a larger cabinet, which will add more low end to your sound.

I love 4x12's but my Bogner sealed 2x12 just kills and works just fine for me.

Ogre
02-15-2007, 12:04 PM
And... each time you add a speaker, and you increase output by 3db, you are doubling the perceptible volume.(all other factors being equal)

mmorse
02-15-2007, 12:20 PM
for a 100 watt amp, two G12T-75 are required, two Vintage 30s are required, and four Greenbacks, though I found that I blew the green backs with only one cabinet, so I had to use a full stack when I was playing my 100 marshall head

That's because Marshall rates their amps clean. A 100 watt will put that out before clipping. Crank it and the amp puts out anywhere from 160 to 180 watts. A 50 watt will produce 60-80 watts when dimed.

cliffc8488
02-15-2007, 12:27 PM
More speakers does not make you louder, your not pushing more air, you are dividing the power between more speakers, which will allow you operate with more power.

Using the same amp more speakers will not produce a higher SPL if more speakers are added.


This isn't quite right. You're ignoring the constructive and destructive interference of multiple speakers in an array. This is the whole premise behind D.I. SPL as you've illustrated only applies to individual speakers or multiple speakers being drive incoherently.

As soon as you arrange speakers in an array the "beam pattern" is affected. This is used to advantage to control the directivity of sound and achieve higher SPL's with the same amount of power.

In the guitar cab case a 4x12 will create a higher SPL due to a narrower beam pattern (higher D.I.).

CC

enharmonic
02-15-2007, 12:34 PM
100db is 100db...be it from a 2x12, 4x12, jet, or screaming baby...loudness is relative, measurement is not.

bluessyndicate
02-15-2007, 12:58 PM
Yeah..i always wondered..."if I drink two shots of tequila simultaneously out of each side of my mouth...will I get more buzzed than if I only shoot one shot of tequila..."

:messedup

John Phillips
02-15-2007, 02:08 PM
Some of you are forgetting a very important aspect. If we are talking tube amps with variable output impedance, then the output taps sound different. The 16 ohm tap uses all of the windings whereas the 8 and 4 ohm taps are using the appropriate fraction of them.Assuming the ratios are correctly chosen and a cabinet of the correct impedance is connected, there is no difference in power or sound between using "all the windings" and using a tap. The OT does not "know" that there are some unused windings, they are electrically irrelevant since no current flows in them. If you built a transformer with a 16-ohm winding with an 8-ohm tap, and another identical transformer except that it only had the 8-ohm winding, both would sound identical when set to 8 ohms, but in one case it would be the "whole winding" and in the other case it wouldn't. "Using the whole winding" implies it should be better, but it has no basis in electrical reality. Using different impedances does sound different, but it's a myth that it's because one or the other uses the "whole" winding. In most Fender amps (for example) the 4-ohm winding is the whole winding.

In fact, with some transformers (older Marshall ones, for example) the ratios are not quite correct and you actually get more power and a bigger sound at 4 ohms than 16.


Whether four speakers are louder than two (assuming the same speakers) depends on the exact speaker characteristics. In theory, dividing the power between double the number of speakers should produce exactly the same result, because each speaker is then getting half the power, which exactly offsets the extra number. But this relies on speakers having a linear sensitivity relative to the power... and they don't. Typically it falls away with increasing power, especially near the upper end of their handling range, so doubling the power input to the speaker does not produce double the acoustic power output. Hence, a 2x12" won't be as loud as a 4x12" with the same power input, because the 4x12"s speakers are operating in a more efficient part of their range. You'll probably notice this much more when the speakers in the 2x12" are not far above the power rating of the amp, eg a 50W amp into a 2x12" with 30W speakers, vs. a 4x12" with the same speakers.

Austinrocks
02-15-2007, 03:36 PM
This isn't quite right. You're ignoring the constructive and destructive interference of multiple speakers in an array. This is the whole premise behind D.I. SPL as you've illustrated only applies to individual speakers or multiple speakers being drive incoherently.

As soon as you arrange speakers in an array the "beam pattern" is affected. This is used to advantage to control the directivity of sound and achieve higher SPL's with the same amount of power.

In the guitar cab case a 4x12 will create a higher SPL due to a narrower beam pattern (higher D.I.).

A 4x12 does not increase the SPL, it just sounds louder because the speakers are off the ground and closer to your ears. If you took a single speaker and set it on your cabinet it would sound much louder because the sound is concentrated into on speaker at ear level.

CC

Seperating speakers does cause interference, and the wave lengths of the frequency certainly show constructive and destructive interference, 1000 Hz is 1.1 feet and so a 6" distance will create destructive interfernce to occur, if you want to see interference in action take two cabinets and set them 6 feet apart, they are unplayable from the same amp, sounds like your running through a phaser as you walk around playing.


Because of interference you are really better off using a single speaker, the interference is constructive and destructive, and depending on where you are the interference changes. It does not all add, which is why most cabinets sound bassier, the bass wavelengths are longer so they don't tend to cancel, they cancel a lot at the high frequencies.

Austinrocks
02-15-2007, 04:09 PM
That's because Marshall rates their amps clean. A 100 watt will put that out before clipping. Crank it and the amp puts out anywhere from 160 to 180 watts. A 50 watt will produce 60-80 watts when dimed.

Correct a tube amp is capable of much more power because the amps are Rated for RMS power, the Peak Power is about twice as high. Most amps are run linearly, the distortion is in the preamp unless your running the Master volume at 10 or 12 on the Fender Hot Rod, or using an attenuator, the distortion is usually from the preamp, to get the power amps to distort really takes a lot of work, and ear plugs, even for the small amps.

Moods
02-15-2007, 04:33 PM
Assuming the ratios are correctly chosen and a cabinet of the correct impedance is connected, there is no difference in power or sound between using "all the windings" and using a tap. The OT does not "know" that there are some unused windings, they are electrically irrelevant since no current flows in them. If you built a transformer with a 16-ohm winding with an 8-ohm tap, and another identical transformer except that it only had the 8-ohm winding, both would sound identical when set to 8 ohms, but in one case it would be the "whole winding" and in the other case it wouldn't. "Using the whole winding" implies it should be better, but it has no basis in electrical reality. Using different impedances does sound different, but it's a myth that it's because one or the other uses the "whole" winding. In most Fender amps (for example) the 4-ohm winding is the whole winding.

In fact, with some transformers (older Marshall ones, for example) the ratios are not quite correct and you actually get more power and a bigger sound at 4 ohms than 16.


Whether four speakers are louder than two (assuming the same speakers) depends on the exact speaker characteristics. In theory, dividing the power between double the number of speakers should produce exactly the same result, because each speaker is then getting half the power, which exactly offsets the extra number. But this relies on speakers having a linear sensitivity relative to the power... and they don't. Typically it falls away with increasing power, especially near the upper end of their handling range, so doubling the power input to the speaker does not produce double the acoustic power output. Hence, a 2x12" won't be as loud as a 4x12" with the same power input, because the 4x12"s speakers are operating in a more efficient part of their range. You'll probably notice this much more when the speakers in the 2x12" are not far above the power rating of the amp, eg a 50W amp into a 2x12" with 30W speakers, vs. a 4x12" with the same speakers.

+1 on both counts.

We have a winner!

<M

mtlin
02-15-2007, 05:25 PM
Whether four speakers are louder than two (assuming the same speakers) depends on the exact speaker characteristics. In theory, dividing the power between double the number of speakers should produce exactly the same result, because each speaker is then getting half the power, which exactly offsets the extra number. But this relies on speakers having a linear sensitivity relative to the power... and they don't. Typically it falls away with increasing power, especially near the upper end of their handling range, so doubling the power input to the speaker does not produce double the acoustic power output. Hence, a 2x12" won't be as loud as a 4x12" with the same power input, because the 4x12"s speakers are operating in a more efficient part of their range. You'll probably notice this much more when the speakers in the 2x12" are not far above the power rating of the amp, eg a 50W amp into a 2x12" with 30W speakers, vs. a 4x12" with the same speakers.

Great explanation! I've wondered why more speakers sounds louder given that the same amount of energy is going into them in any event. Your explanation makes perfect sense.

rockon1
02-15-2007, 05:36 PM
not[/i] produce double the acoustic power output. Hence, a 2x12" won't be as loud as a 4x12" with the same power input, because the 4x12"s speakers are operating in a more efficient part of their range. You'll probably notice this much more when the speakers in the 2x12" are not far above the power rating of the amp, eg a 50W amp into a 2x12" with 30W speakers, vs. a 4x12" with the same speakers.


Thank you for explaining what my ears tell me but I couldnt explain every time this "discussion" comes up!!!!!!! :)