#1
I'm thinking about improving my tone by some upgrades in speaker or maybe cab. my amp is a blackheart 15W all-tube; the cab I have now is a matching closed-back blackheart 1x12 with stock 75W eminence; my genre is hard rock, lil bit of old school metal; my purpose is to tighten up the bass & add some punch & create a more "open" tone. I use my rig for both recording & live situation (mic'ing it up)

I've come up with some plans:
1/ get a better speaker for the 1x12 : the cheapest I'm looking at the G12H30 (saw this guy on youtube play a blackheart thru it......killing tone but lack some "air". may it be 'coz of the camcorder's mic :confused and the Vintage 30 (lot of modern rockers use it but it's told to have harsh treble) and wondering which give more tight low-end & punch. can I get the tone I want with it?

2/ get one more 1x12 & 2 new speakers : less cheap what I'll be concerning is the efficiency & the mic'ing method. can I get the upgraded sound by mic'ing only one cab (esp. when using 2 diff. spkrs) ? or should I use & blend 2 mics?

3/ get a 2x12 with good spkrs: pricey any diff. between two 1x12 cabs and one 2x12??

4/ I got an offer of a marshall 1960A 4x12 : it's a hard stretch!! the ultimate solution. but is it the only way?

Thanks in advance
Last edited by Duncan_amateur at Jan 26, 2009,
#2
I would just get the 412 if you have the space for it, but otherwise there's not much difference between two 112s and a 212 cabinet.

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#4
I can endorse the G12H-30. It's an excellent speaker for any kind of rock.
Although to be honest, if you want low-end and punch, take a look at the G12K-100. It's like a Vintage 30 but less treble and more low-end.
#5
You shouldn't ask questions like these with techies around. I could write for hours. here are a few thoughts though.

from your description it sounds as if your cab is underdamped. Manufacturers put speakers in cabs that are too small to control the drive unit at low frequencies. They gain a little extra bass and efficiency in return for losing tightness and articulation in the bass. It is possible that the eminence would give you a better sound in a different cab. If you give me the actual model of driver and the dimensions I could calculate a cab size for you.

You've got a valve amp. You need to match the speaker to the amp or you will lose outout and may strain the amp. Does the amp have sockets for 4,8,16 ohms? look for my column on matching speakers and amps for more details.

If you have two identical speakers then you only need to mic' up one as they will sound the same.

Using two different speakers is interesting ( they must have the same ohms) as their frequency responses will be different and subjectively this tends to smooth out the sound.

using a 2x12 or a 4x12 should give you an increase in sound level of about 3dB equivalent to doubling the output of the amp. It might be much more or less than this depending on the efficiency of the drive units though. If my memory is any good then I think the vintage 30's are particularly efficient. 4x12 Marshall anyone?
#6
Quote by Phil Starr
using a 2x12 or a 4x12 should give you an increase in sound level of about 3dB equivalent to doubling the output of the amp.

Sorry to bother you, but can you please explain how this works?

I've been looking for an answer to this for the past few days and I cant figure it out.
A metal band?
Gear:
A Guitar with an LFR > Korg Pitchblack > Behringer EQ > Hardwire CM-2 Overdrive Boss SD-1 > Hardwire CR-7 Chorus>
Orange Tiny Terror >
LzR Engineering 212 cab

My other amp can run Crysis
#7
Ok a lot depends upon the amps but basically if you connect two speakers in parallel then each will be shifting the same amount of air so twice the acoustic watts and 3dB louder.

A 4x12 will be connected in series parallel (see matching speakers and amps in the columns) eachspeaker will be moving half as far as a single speaker but there are four of them so again you are shifting twice as much air and you are three dB louder. now though, you are not drawing as much current from the amp which will be less stressed and you could always add a bigger amp if you wanted.

Oops I think you might want the dB's explained too. This is a bit more complicated to explain because it involves how the ear/brain interpret what you hear. Could take a few thousand words.

How about this. one decibel is the smallest increase in sound you would normally detect. Turning your hifi up a notch. If you want to turn it up three notches you need twice as much power. It won't be twice as loud though. You need ten times the power to do that.
#8
Quote by Phil Starr
Ok a lot depends upon the amps but basically if you connect two speakers in parallel then each will be shifting the same amount of air so twice the acoustic watts and 3dB louder.

Wrong. The amp is producing the same amount of power, so with a two speaker arrangement the same amount of power will be spread over 2 speakers. Each speaker would produce about half as much acoustic power as a single speaker driven by the same amp. The only difference in volume would be from the speaker efficiency changing due to not being driven so hard, but this probably only happens (noticeably) at extreme levels, well above the rated power of the speaker.

Power out = Power in x Efficiency

Quote by Phil Starr
A 4x12 will be connected in series parallel (see matching speakers and amps in the columns) eachspeaker will be moving half as far as a single speaker but there are four of them so again you are shifting twice as much air and you are three dB louder. now though, you are not drawing as much current from the amp which will be less stressed and you could always add a bigger amp if you wanted.

You mean a quarter as far. The overall current draw on the amp will be the same providing that the impedance is set correctly.
So overall, there is 4x the surface area moving 1/4 the distance, which means the total air displacement will be equal to that of a single speaker (assuming the overall efficiency doesn't change, and the power rating for the single speaker is not exceeded)

Quote by Phil Starr
Oops I think you might want the dB's explained too.

Let me.

Pl = 20Log(P/P0)

Pl= dB
P = power in watts
P0 = Reference power (1x10^-5)


However, 412s generally sound better because they are bigger, therefore they have a larger resonant chamber, lower resonant frequency, and therefore more low end.
A metal band?
Gear:
A Guitar with an LFR > Korg Pitchblack > Behringer EQ > Hardwire CM-2 Overdrive Boss SD-1 > Hardwire CR-7 Chorus>
Orange Tiny Terror >
LzR Engineering 212 cab

My other amp can run Crysis
Last edited by FischmungaXTR at Jan 27, 2009,
#9
Ok not so much wrong as over simplified. I started out by saying a lot depends upon the amp; basically whether it is valve or transistor and what sort of power supply it has. All my textbooks (Colloms , Dickason for two) state that there is a 3dB gain in output from 4 speakers in series parallel and this to me and i guess to you seems counterintuitive. surely the same voltage across the same impedance should produce the same power or the first law of thermodynamics is broken. I always assume no maths in my answers as most of them are written for musicians not scientists. even so the textbooks are all in agreement on this I checked a couple of days ago as I am researching an article for UG. I haven'thad time to do the maths yet which is where the answer must lie. I can only say though that the measurements I have found on cabinets with multiple drivers confirms the 3dB gain. It may be to do with efficiency gains and coupling to the air. When I get time I will either do the maths or find a proof but if you get there before me please send me your answer proof or disproof. pm me if the thread has disappeared

sorry I should have read your post more accurately. with a transistor amp with an adequate power supply which acts as a voltage amplifier.

The voltage across each speaker in a parallel circuit will be constant and each speaker will travel as if it alone were connected across the amplifier. The amplifier will supply more current and hence more power until it runs out of current capacity either because the transformer becomes overloade or the smoothing capacitors run out of steam. You do get a 3dB increase for this reason.

The voltage across the speakers in a series connection will be half for each speaker so the excursion which is proportional to voltage at low signal levels (up to Xmax)
will also be half as I stated. As Ive said I'm still not happy that this is the complete answer as I don't like the idea of getting something for nothing.

by the way to calculate the dB change use;

dB=10log a/b for power changes and dB=20 log a/b for voltage or current changes.
Last edited by Phil Starr at Jan 27, 2009,
#12
Yea, sorry about the thread hijack, but I have never seen this explained on UG and it seems a lot of users are just blindly stating that you get a 3 dB increase simply by doubling the speakers.

Phil: Seems like it can be explained for transistor amps which don't need an exactly matched impedance. I guess this comes from car audio systems, where the amps usually state something like "must be greater than 4 ohms". I guess that in this case, connecting more speakers (in parallel) would draw more current and there would be a 3dB loudness gain.

I suspect it doesnt apply for valve amps, but I can't be sure about that. Good luck with your research. I hope you find the answer.
A metal band?
Gear:
A Guitar with an LFR > Korg Pitchblack > Behringer EQ > Hardwire CM-2 Overdrive Boss SD-1 > Hardwire CR-7 Chorus>
Orange Tiny Terror >
LzR Engineering 212 cab

My other amp can run Crysis
#13
Quote by Horlicks
I can endorse the G12H-30. It's an excellent speaker for any kind of rock.
Although to be honest, if you want low-end and punch, take a look at the G12K-100. It's like a Vintage 30 but less treble and more low-end.

+1 i have a celestion g12k and it made a huge difference with the sound of a VJ.
big bottom end the mids are full and the is top end is subdued not overpowering. 1x12 with g12k is plenty of speaker to say the least BIG SOUND!!
http://professional.celestion.com/guitar/products/classic/detail.asp?ID=32
Last edited by mmjohn at Jan 28, 2009,
#14
thanks for the advice. I heard good things about it as well but the users said they use it in a 4x12 so I doubt it'd be efficient in a 1x12 do you have any demo of it?

btw, could any of you please explain the speaker break-up to me? is it tonally good or not? It really confuses me. some say it relates to the wattage of the speaker, some say not
Last edited by Duncan_amateur at Jan 30, 2009,