Will I get to crank my amps more with a 2x12 instead of a 4x12

[monkeysuit]

Played some shows with the 5150 recently and always had to play it with the post gain on ~2 as it would have been to loud otherwise. Will I be able to turn it up a bit more with a 2x12 to get the volume level I have on 2 with the current 4x12?

[Silent Heart]

Played some shows with the 5150 recently and always had to play it with the post gain on ~2 as it would have been to loud otherwise. Will I be able to turn it up a bit more with a 2x12 to get the volume level I have on 2 with the current 4x12?

 

 

No, it shouldn't be different assuming both the 2x12 and 4x12 can adequately "handle" the wattage that the 5150 is putting out. Use a power attenuator if you want power tube saturation at low volumes.

[metareal]

Perceived volume on a 4x12 will be higher than on a 2x12 simply because you are moving more air.

So yes in theory you will have to turn up your amp to push out more power to achieve the same volume when using a 2x12 as opposed to a 4x12. As by how much I cant really tell you...it also depends massively on which speakers and what cabinet...

Ed.

[metareal]

 

No, it shouldn't be different assuming both the 2x12 and 4x12 can adequately "handle" the wattage that the 5150 is putting out. Use a power attenuator if you want power tube saturation at low volumes.

 

 

That is not correct, power is not equal to dBs.

 

Although an attenuator will definately help you!

[monkeysuit]

thanks, i know it won't make much of a difference i was just wondering if any at all. an attenuator would be an option but i think i'll try the 5150 bias mod first as i read it makes it sound better at low volumes...

[Sixtonoize]

 

That is not correct, power is not equal to dBs.

 

isn't true, either...for every doubling of power, you increase the volume by 3db. There's a direct mathematical relationship between power and db.

[Say Ocean]

And this: isn't true, either...for every doubling of power, you increase the volume by 3db. There's a direct mathematical relationship between power and db.

 

 

If speakers, circuitry, room etc are all the same.

[metareal]

That's not correct, either. The real answer is this: There are too many factors to take into account to adequately make a prediction. It depends ENTIRELY on the 2x12 and the 4x12 that you're comparing, and there are about a dozen factors that go into the equation, but realistically, it won't make enough of a difference to really matter. Maybe you'll get to turn your Post gain up to 2.5 instead of 2, but that's about it. EDIT: And this: isn't true, either...for every doubling of power, you increase the volume by 3db. There's a direct mathematical relationship between power and db.

Hi Sixtonoize,

I am going to stand by my point if you dont mind!

The fact that you will push more air with 4 speaker rather than 2 is just a fact. You cant really argue with that. Whether it will make a big difference I have already said that I am not sure about it.

On the second point you are perfectly right, there is a mathematical relation between power and dB and despite being proportional they are NOT EQUAL.

Cheers
Ed.

[Sixtonoize]

Hi Sixtonoize, The fact that you will push more air with 4 speaker rather than 2 is just a fact. You cant really argue with that. Whether it will make a big difference I have already said that I am not sure about it.

 

 

But aren't you pushing twice as much air half as hard?

 

If you sent 100 watts into your cab, each speaker in a 2x12 gets 50 watts but the speakers in a 4x12 cab only get 25 watts each.

 

Really, what happens when you double the number of drivers (in a completely ideal situation, and keeping everything else equal), you increase the efficiency of the speaker array by 3db. However, a guitar cab is FAR from an ideal system...there's a substantial volume change, speaker interaction, baffle geometry changes, and a million other factors to take into account when you compare a 4x12 to a 2x12. I've heard plenty of 2x12s that sounded louder than 4x12s with the same speakers. It's entirely based on the design of the two cabs that you're comparing. In my experience, a 4x12 will have more bass presence, thump, and sound (to use an old cliche') bogger, but not louder. A 2x12 will sound more mid-heavy, tighter, and sit better in a mix (and consequently be easier to hear) because they tend to put out less bass.

 

Of course, assuming that everything is ideal, a 3db increase in SPL really isn't a significant amount of volume. It's negligible.

 

And yes, I guess saying that "wattage and db are not equal" is true...but it makes you sound like you don't know anything about the relationship between the two when you say it.

[guitarbilly74]

 

But aren't you pushing twice as much air half as hard?

 

 

yes but half as hard does not mean "half the volume" .. remember twice the power only means a 3dB difference. Let's say a speaker pushing 50w would produce 10dB (random number just to make it easier). The same speaker pushing 25w would produce 7dB (3dBs less)

 

so a 100w through a 2x12 would give you 20dBs of volume (10dBs per speaker x 2)

same amp through a 4x12 with the same speakers would give you 28dB (7dBs per speaker x4)

 

Again these numbers are for illustration purposes only.But in general an amp through a 4x12 will be louder than the same amp through a 2x12 - all other things being equal.

[Sixtonoize]

so a 100w through a 2x12 would give you 20dBs of volume (10dBs per speaker x 2) same amp through a 4x12 with the same speakers would give you 28dB (7dBs per speaker x4) Again these numbers are for illustration purposes only.

 

But that's not even a remotely correct illustration. Adding speakers doesn't create a linear increase of SPL.

 

[bemymonkey]

Twice as much wattage gives you +3dB, and twice as much speaker area gives you +3dB as well.

 

Going from a 4x12" to a 2x12" gives you -3dB, which isn't a lot. If you want to crank the amp, get a 1x12" (-6dB) with a very inefficient speaker, and a power soak to go with it all.

 

Adding speakers doesn't create a mathematical increase of SPL.

 

Uh... yeah it does. Every doubling of speaker area adds 3dB.

[guitarbilly74]

Played some shows with the 5150 recently and always had to play it with the post gain on ~2 as it would have been to loud otherwise. Will I be able to turn it up a bit more with a 2x12 to get the volume level I have on 2 with the current 4x12?

 

 

A smaller cab will help but not to the extent that you need. You need an attenuator.

Another thing that might help a lot is to turn your cab so it's facing the wall instead of facing the audience, then mic it and use the stage monitors to hear yourself.

[Brian May]

What he said just above me! If you want power tube saturation as mentioned earlier get an attenuator. Also a 1x12 combo at 50w is not as loud as a 50w head on a 4x12 cab assuming were talking of speakers of equal efficiency. I noticed this ages ago when I had a DSL50 head, I had a 2x12, and a 4x12 cab and it was notciable the perceived volume differences. I think many amps today are just way too powerful for most peoples needs. Small 1x12 or 2x12 tube combos of say 20-30w is as much as many of us will ever need - even in a giggin capacity. Take a look at a Vox AC30 even - 33w 2x12 combo and that is way too loud for most bands to crank!! It can help to turn the amp around so its facing away from the audience, but the sound you get from that then may sound a little dull to your own ears unless you've got good on stage monitors throwing sound back at you from the amp as its mic'd up.

[Sixtonoize]

Uh... yeah it does. Every doubling of speaker area adds 3dB.

I guess I can't bitch about you calling me out on semantics when I did the same thing 5 posts ago.

Fix'd

[metareal]

ha! I see what you are saying that is a general misconception.

You are right in saying that in real life there are so many factors that make this comparison a bit inpractical. and yes some 2x12 can sound louder than some 4x12 especially if you take into account room factors and orientation.

However if we are talking about pure volume 4 speakers will always push more air than a 2x12. Even if you consider that the power is halved, as you pointed out volume is measured in dB's which is not on a linear scale (just like our hearing it is on a logarithmic scale) and halving the power wont halve the volume.

Sorry I am not great at explaining things!

[guitarbilly74]

But that's not even a remotely correct illustration. Adding speakers doesn't create a linear increase of SPL.

 

I KNOW it's not that cut and dry. That's why I said these numbers are for illustration purposes only.

 

My point is that doubling the number of speakers you are cutting the power each speaker will recieve in half but you are NOT cutting in half the volume they are producing, so at the end you are getting a higher SPL. No it's not going to be twice as loud, but it will definitely be LOUDER than it was before.

[Brian May]

I remember the problem I used to have in my old band - I often got told to turn down my amp (DSL50) as I was too loud out front. Yet onstage being right beside the caveman drummer I could barely hear myself! Sound is funny like that - you can be sat almost right on top of your amp and not hear it, yet the audience is cowering as they get their faces melted off out front!

It used to really frustrate me - it wasn't even like i was mad loud or anything - I only wanted to hear myself without any difficulty. But thats what you get when your close to a loud drummer and have no foldback monitors throwing your own guitar sound back at you! We had limited monitors and our bass and guitars never got anywhere near them! All we got was vocals n keyboards through 'em.

[Sixtonoize]

I KNOW it's not that cut and dry. That's why I said these numbers are for illustration purposes only . My point is that doubling the number of speakers you are cutting the power each speaker will recieve in half but you are NOT cutting in half the volume they are producing, so at the end you are getting a higher SPL. No it's not going to be twice as loud, but it will definitely be LOUDER than it was before.

 

 

But it IS cut and dry.

 

Doubling the speakers increases efficiency of an array by 3db.

 

That's it. Not 8. 3. Every. Single. Time.

 

Of course, that's neglecting all of the million other factors that go into the equation.

 

So:

 

1 watt into 1x12 with a V-30 = 99db

1 watt into 2x12 with V-30s = 102db

1 watt into 4x12 with V-30s = 105db

 

Of course, a guitar cab isn't ideal. The frequency response changes, the drivers aren't aligned ideally, there are standing waves in the cab, etc.

 

BUT, assuming a perfectly designed enclosure, it's a 3db difference.

 

Which ain't much.

[mick8882003]

Ok here is my two cents worth, sound transmission is frequency dependent. To illustrate this take your typical home stereo, woofers and tweeters. The size of your typical tweeter is much less that your typical woofer, the reason, it is much easier to generate and transmit a high frequency than a low frequency. This is mainly due to the fact that more air mass must be moved as you move down in frequency.
Ok, so your halving the number of speakers. In effect what you are doing just limiting the bass response of your amp. All you have to do to make up the treble is increase the volume just a touch. The bass, however, not so.
To summarize, you will get the same effect by increasing the volume, *but* you will not "push as much air"

Advice: look for a decent ported cab, like the Genz Benz 2*12 (this is not a plug for them) - Ported = better bass response, by design

[monkeysuit]

A smaller cab will help but not to the extent that you need. You need an attenuator. Another thing that might help a lot is to turn your cab so it's facing the wall instead of facing the audience, then mic it and use the stage monitors to hear yourself.

I'm thankful for every bit i can put the post gain up
Nah, I don't want poweramp saturationor so and it's not that my amps sound painfully bad unless the master is way up.
Actually with the cobra I don't have that problem as it sounds great once the master crosses 9 o'clock and thats been cool with all sound guys so far. Only the 5150 has a fair amount of bees around 2 and with every bit i move it up a couple bees go away.

Turning the cab to face away from the audience is definitely worth a try, i'll give it a shot at the next show

[bemymonkey]

I guess I can't bitch about you calling me out on semantics when I did the same thing 5 posts ago. Fix'd

Sorry, I couldn't resist

[GCDEF]

Perceived volume on a 4x12 will be higher than on a 2x12 simply because you are moving more air. Ed.

 

 

Please stop this move more air crap. Just nip it, nip it in the bud.

[GCDEF]

Twice as much wattage gives you +3dB, and twice as much speaker area gives you +3dB as well. Going from a 4x12" to a 2x12" gives you -3dB, which isn't a lot. If you want to crank the amp, get a 1x12" (-6dB) with a very inefficient speaker, and a power soak to go with it all. Uh... yeah it does. Every doubling of speaker area adds 3dB.

Why is this such a difficult concept??? Adding speakers is not the same as adding wattage. Power comes from the amp. Speaker area has nothing to do with volume. Think about it. If all it took to add sound was lots of speakers, a stadium sized PA could be powered with a clock radio.

Once more for simplicity. Power comes from the amp, not speakers. Adding passive devices does not add power.

[mick8882003]

Why is this such a difficult concept??? Adding speakers is not the same as adding wattage. Power comes from the amp. Speaker area has nothing to do with volume. Think about it. If all it took to add sound was lots of speakers, a stadium sized PA could be powered with a clock radio. Once more for simplicity. Power comes from the amp, not speakers. Adding passive devices does not add power.

 

 

Its not that simple, it also depends on the efficiency of the cab.