Quick quiestion on External Cabnets

[TRex]

If I was to run my Jet city JCA2212 into either a 2x12 or another 1x12 as a extention to the 1x12 in the combo, how much louder would it be?

I hear stories of guys running 5 watters into 4x12 cabs and getting giggible levels, where a 50watt amp would normally be used.

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[Chickenwings]

Re: Quick quiestion on External Cabnets

It wont be much louder because you are sharing the wattage between two speakers- and its twice as much to carry to a gig.
If you really want to make it louder, get a more efficient speaker. This is the secret behind the early boogie amps and how people used to say that a 1x12 combo could be louder than a 4x12.
Something with a big beefy magnet and an efficient voice coil like an eminence wizard, or a swamp thing depending on the kind of flavours you like. You will definitely get you a large extra serving of volume, punch and detail.
Maybe even celestion vintage 30, or an EV too. See what you can find for the right price and with the tones you like.
If you decide to do some research, what you are looking for on the speaker spec. sheet is MAx db (decibels), or max spl@1w (sound pressue levels). A difference of 3db is an appreciable difference to the ear, whereas a 6db increase sounds roughly twice as loud. (ie a 103db speaker will seem twice as loud as a 97db speaker like a greenback).
Different companies will obviously have slight variances in how they test, so eminence ratings might not line up exactly with celestion, but seeing as you already have an eminence speaker, it will be pretty easy. Another pretty damn idiot proof test is simply to look at the size of the magnet. If it has a much bigger chunkier looking magnet than the speaker you have, you can be pretty sure the speaker will be a lot louder.
This is a thread about your amp:

https://forum.seymourduncan.com/showthread.php?240561-Jet-city-Eminence-speakers

and a video:

fwiw, the eminence wizard is appreciably louder than the vintage 30 which the speaker in the video is modelled on.

[SlyFoxx]

Re: Quick quiestion on External Cabnets

Given an extension cab of like sensitivity you'd get about 3 more dB....not much. But you would generate a wider sweet spot as the horizontal dispersion increases with more speakers.

I've gigged small venues with 5 watts and two V30's..but that was for my distortion channel. I'd use 30 watts for my clean. (Mesa Lonestar Special)

[TRex]

Re: Quick quiestion on External Cabnets

It wont be much louder because you are sharing the wattage between two speakers- and its twice as much to carry to a gig.
If you really want to make it louder, get a more efficient speaker. This is the secret behind the early boogie amps and how people used to say that a 1x12 combo could be louder than a 4x12.
Something with a big beefy magnet and an efficient voice coil like an eminence wizard, or a swamp thing depending on the kind of flavours you like. You will definitely get you a large extra serving of volume, punch and detail.
Maybe even celestion vintage 30, or an EV too. See what you can find for the right price and with the tones you like.
If you decide to do some research, what you are looking for on the speaker spec. sheet is MAx db (decibels), or max spl@1w (sound pressue levels). A difference of 3db is an appreciable difference to the ear, whereas a 6db increase sounds roughly twice as loud. (ie a 103db speaker will seem twice as loud as a 97db speaker like a greenback).
Different companies will obviously have slight variances in how they test, so eminence ratings might not line up exactly with celestion, but seeing as you already have an eminence speaker, it will be pretty easy. Another pretty damn idiot proof test is simply to look at the size of the magnet. If it has a much bigger chunkier looking magnet than the speaker you have, you can be pretty sure the speaker will be a lot louder.
This is a thread about your amp:

https://forum.seymourduncan.com/showthread.php?240561-Jet-city-Eminence-speakers

and a video:

fwiw, the eminence wizard is appreciably louder than the vintage 30 which the speaker in the video is modelled on.

Ok so I would get more by getting a speaker of a larger dB rating.

I will probably want it in an external cab, and I can run it with or without my internal speaker to my needs, but keep my stock for home use and small gigs as it is loud enough for that.

Given an extension cab of like sensitivity you'd get about 3 more dB....not much. But you would generate a wider sweet spot as the horizontal dispersion increases with more speakers.

I've gigged small venues with 5 watts and two V30's..but that was for my distortion channel. I'd use 30 watts for my clean. (Mesa Lonestar Special)

@both: To my knowledge, the decibel scale is one that the original power is multiplied by 10^(x/10), where x is the number of decibels in the change. This makes 3db a near perfect doubling difference. So do speakers not deliver that in reality?

The wider spread should help for sure on larger stages.

[SlyFoxx]

Re: Quick quiestion on External Cabnets

10dB louder is considered roughly twice as loud. 3dB louder is a noticeable difference but not a large one. The confusion stems from the fact that when you double the power you get about 3dB more volume. To get 10dB more volume from a given rig you need 10 times the power. In short, double the power doesn't equal double the volume/SPL. Number of speakers and their operating environment such inside or outside and proximity of reflective surfaces can alter things as well.

[TRex]

Re: Quick quiestion on External Cabnets

Ok, sorry I found my error.

My formula refers to intensity, not loudness.

So 10db=roughly 2x volume

[DrNewcenstein]

Re: Quick quiestion on External Cabnets

Case in point: my Carvin VE212 cabinet was noticeably louder than my singer's TubeWorks 4x12, both of us using identical heads, with identical settings. We swapped rigs and he was then louder through mine than I was through his. The 2x12 was rated for 300w, 4 Ohms. Not sure what his 4x12 was rated for. I'm assuming 300w at 8 or 16 Ohms.

[IM4Tone]

Re: Quick quiestion on External Cabnets

Given an extension cab of like sensitivity you'd get about 3 more dB....not much. But you would generate a wider sweet spot as the horizontal dispersion increases with more speakers........

This is not correct. Given an extension cab of like sensitivity will yield no more dB whatsoever. It will give a different perception due to the dispersion. And BTW, 3 dB is noticeable.

This commonly stated fallacy stems from the fact that if you take (for example) a 50 watt amp played into a given single speaker, a second identical speaker powered by an additional 50 watt amp will yield an additional 3 dB. That same single 50 watt amp driving both (2) of the identical speakers results in each of those speakers 'seeing' 25 watts, and the dB output of the pair being the same as if driving only one.

[TRex]

Re: Quick quiestion on External Cabnets

Wait, so no real difference will be made? Just a perceived difference?

I guess I'll have to get a louder speaker for a larger gigs then?

[zzmoore]

Re: Quick quiestion on External Cabnets

Wait, so no real difference will be made? Just a perceived difference?

I guess I'll have to get a louder speaker for a larger gigs then?

That is a tricky way to look at things.
While you need more power or more efficiency to get more Volume.....additional speakers Can Make a Big Difference.
You MAY have enough Power/Volume already..... but imagine being able to have another Pair Of Speakers on the other side of the stage for example. Not only will you be pushing more air, but you will be pushing it in a much larger area, and in space that was previously unavailable to your amp. An extension cabinet can be a Big Help.
You need to identify what it is that you really need to accomplish.
good luck

[IM4Tone]

Re: Quick quiestion on External Cabnets

Wait, so no real difference will be made? Just a perceived difference? ..........

.............It will give a different perception due to the dispersion............

zzmoore's comments are true, for sure!

[TRex]

Re: Quick quiestion on External Cabnets

That is a tricky way to look at things.
While you need more power or more efficiency to get more Volume.....additional speakers Can Make a Big Difference.
You MAY have enough Power/Volume already..... but imagine being able to have another Pair Of Speakers on the other side of the stage for example. Not only will you be pushing more air, but you will be pushing it in a much larger area, and in space that was previously unavailable to your amp. An extension cabinet can be a Big Help.
You need to identify what it is that you really need to accomplish.
good luck

Ok, so more speakers will increase the area at which I am heard, without increasing the total volume?

Sorry, I'm not well versed in the physics of sound.

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[IM4Tone]

Re: Quick quiestion on External Cabnets

Ok, so more speakers will increase the area at which I am heard, without increasing the total volume?

Sorry, I'm not well versed in the physics of sound.

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It will do that.

[SlyFoxx]

Re: Quick quiestion on External Cabnets

Just to put this to the test (and to rest) I just drug out my 4x12 cab (a 20 year old Carvin with 4 identical British Series speakers) and my Marshall. Set the rig to run as a 2x12 into 4 ohms as per the cabs specs. Set the Marshall to a decent amount of grind as the natural compression smooths out the volume. Set the dB meter aimed dead center at the cab about 3 feet back in the 90dB range. Adjusted the amp volume so as to read 92dB on the meter with the guitar full up as hard as I could strike it. Then I added the other two speakers into the equation going from the 4 ohm hole to the 8 ohm hole to match the new impedance. Guess what? 4 more dB. Yes, more speakers makes for a more efficient use of your amp's watts.

[IM4Tone]

Re: Quick quiestion on External Cabnets

The difficulty with a 'test' as you've made is that the amp's wattage output can/will vary with different impedance loads. If you had a way to measure the exact wattage output of the amp, the 'test' would be more valid.

Laws of physics are just that....laws/facts. Wattage (a measurement of electrical energy) is converted to dB (a measurement of SPL or sound energy) by the speaker(s). If the speakers are all identical sensitivities, they can't individually nor collectively create more energy in the conversion of wattage to dB.

I applaud your effort to attempt to scientifically test this premise, but something other than 4 vs 2 speakers varied in your test to cause a different reading. There are many possible contributors......total impedance load on the amp (additionally affected by different windings on the output transfer when the amp's impedance switch is changed), different frequencies (sensitivity does vary with freq.), pick attack, and the actual sound meter itself. My sound meter can vary 2 to 4 dB with no changes of the amp's knobs into the same cab, even when I think I've played the same notes with the same attack.

Don't buy into the internet chatter (this includes what I have to say since I'm an unknown, credibility-wise).....review your physics, or consult a bona fide expert in physics.