Speaker choices

robdynamite

Right, I'm going to try and make this whole post as simple as I can.


Basically I've acquired a Marshall 2049 2x12 cab (purely because of it's vintage/cool status, rather than practicality, obviously?) and I used a jcm 800 2204 50w head.

I currently run the head through a 1960a 300w cab

The speakers in the 2049 are pretty dire and the cab is rated to 50w, I'm wanting to swap out the speakers for something better/more my tastes and I'm thinking greenbacks.

My questions are;

1. Will greenbacks be loud enough (the cab will be used/needed for gigging with a full band as I've never had an issue with headroom with my 1960 cab)

2. What wattage speakers should I be looking at because greenbacks seem to have quite a low wattage in comparison to other speakers.

Also can I point out that this may all sound very idiotic but amps are something I know literally NOTHING about and after many years of playing I'm a little ashamed to admit that, so go easy please haha.

Thanks!

ICBM

Creamback G12M-65 in the top and Creamback G12H-75 in the bottom.

Trust me on this . Not only are they some of the best-sounding speakers Celestion have ever made - very like slightly tighter, higher-power-rated versions of the G12M-25 Greenback and G12H-30 - the combination is absolutely wonderful.

It will also give you a 130W cabinet which can safely be played at absolutely full crank with a 50W head, should you wish to. And yes, it will definitely be loud enough .

cosmiccarrot

I'd go for both creamback 65's, allowing for them to break in (unless you can find a couple used). A mate had one of these years back, think you might find it a bit 'boomy' compared to the tighter more focused sound of your 4x12, might be worth blocking the port hole in the baffle as a quick test. I think marshall may have felt it necessary to give the sound a more open-back tone? as from all accounts the Artist range was a bit of a 'fenderish' project.
Looks in good condition. you should be able to sell the existing Blackback 30watters if there in good condition, think there 55hz bass cones?

robdynamite

ICBM said:

Creamback G12M-65 in the top and Creamback G12H-75 in the bottom.

Trust me on this . Not only are they some of the best-sounding speakers Celestion have ever made - very like slightly tighter, higher-power-rated versions of the G12M-25 Greenback and G12H-30 - the combination is absolutely wonderful.

It will also give you a 130W cabinet which can safely be played at absolutely full crank with a 50W head, should you wish to. And yes, it will definitely be loud enough .

Ace, I'll have a look into that.

Am I right in thinking that that is a pretty common speaker combination?

Also, how will the speakers give a 130w output? Am I missing something or is that a typo? haha

robdynamite

cosmiccarrot said:

I'd go for both creamback 65's, allowing for them to break in (unless you can find a couple used). A mate had one of these years back, think you might find it a bit 'boomy' compared to the tighter more focused sound of your 4x12, might be worth blocking the port hole in the baffle as a quick test. I think marshall may have felt it necessary to give the sound a more open-back tone? as from all accounts the Artist range was a bit of a 'fenderish' project.
Looks in good condition. you should be able to sell the existing Blackback 30watters if there in good condition, think there 55hz bass cones?

Yeah, this cab sounds absolutely massive in comparison to my 4x12 and I assuming that's fully attributable to the port hole.

ICBM

robdynamite said:

Am I right in thinking that that is a pretty common speaker combination?

I don't know if it's really common since the speakers haven't been out that long. A G12M-25 and a G12H-30 is a classic combination though, and the two Creambacks sound very similar but with more power rating. Despite the apparent difference in sensitivity (97dB vs 100db) they sound exactly the same volume too - the more midrangy M sounds louder than you would expect and the deeper/cleaner H sounds quieter.

robdynamite said:

Also, how will the speakers give a 130w output? Am I missing something or is that a typo? haha

Not a typo. The rating of a two-speaker cab (with equal impedance speakers) is twice that of the lower-rated speaker, and 2 x 65W = 130W. That's how much power it can take before the G12M reaches its limit.

drwiddly

I recently replaced the speaker in a 1x12 combo with a Neo Creamback and it sounds great. Might be an option if you need a lighter cab?

ICBM

drwiddly said:

I recently replaced the speaker in a 1x12 combo with a Neo Creamback and it sounds great. Might be an option if you need a lighter cab?

Given the sheer amount of plywood in that thing I doubt it would make any noticeable difference .

I’m interested to try one of these though.

drwiddly

Lol!
I was surprised at how good it sounded tbh. Swapping out a speaker is always a bit of a gamble and, as it was replacing a CL80, it could have been disappointing. It's about half the weight of the CL80 so a noticeable difference in portability too.

robdynamite

ICBM said:

robdynamite said:

Am I right in thinking that that is a pretty common speaker combination?

I don't know if it's really common since the speakers haven't been out that long. A G12M-25 and a G12H-30 is a classic combination though, and the two Creambacks sound very similar but with more power rating. Despite the apparent difference in sensitivity (97dB vs 100db) they sound exactly the same volume too - the more midrangy M sounds louder than you would expect and the deeper/cleaner H sounds quieter.

robdynamite said:

Also, how will the speakers give a 130w output? Am I missing something or is that a typo? haha

Not a typo. The rating of a two-speaker cab (with equal impedance speakers) is twice that of the lower-rated speaker, and 2 x 65W = 130W. That's how much power it can take before the G12M reaches its limit.

riiiight. Okay, some of this is beginning to stick now, ha!

So in regards to ohmage, is an 8ohm speaker more powerful than a 16? or am I just way off now?

ICBM

robdynamite said:

riiiight. Okay, some of this is beginning to stick now, ha!

So in regards to ohmage, is an 8ohm speaker more powerful than a 16? or am I just way off now?

Well... by itself, the impedance has nothing to do with the power rating or output of the speaker at all. 

The power *rating* (ie the maximum it can take before it blows) of the speaker and the power *output* (ie the maximum it will deliver) of the amp aren't related. Using a higher-power speaker will not draw more power from the amp if the impedance is the same.

But the impedance *can* determine how much power is drawn from the amp. Not usually with a valve amp, where you set the amp impedance to match the speaker - it will then deliver the same power, and in fact if you mismatch in *either* direction you get less power.

But with a solid-state amp which usually does not have an output transformer or an impedance selector, typically you get more power at a lower impedance, down to the amp's rated minimum (usually 4 ohms, but not always).

Does that make any sense? The difference between valve and solid-state is a source of confusion, I know.

Why speaker ratings and amp power matter is that you don't want to put more power into the speaker than it can take, or you may blow it. For a guitar amp, you can't even really go by the amp's power rating alone, since they're designed to distort, and a fully distorted amp can put out up to twice the rated power. So to be safe, ideally you need the cabinet to be rated for at least twice what the amp is. (This does vary a bit depending on the speaker manufacturer, some are more conservative than others.)

This is also mostly true for bass amps, since they will often be accidentally pushed into distortion (or very close to it) even if the player thinks they're playing clean.

[Confusing bit, skip if you're already lost - this isn't true for PA and hi-fi speakers since it's *distortion* which tends to damage those rather than outright power, so usually you want the amp rated slightly higher than the speakers so you can be sure the amp won't distort, and this is often given as advice by 'technical' types who know that... but don't pay any attention to that for guitar amps!]

robdynamite

wow. that's some hefty info.

Thanks very much for that!

ICBM

What it all means is that for your amp and cab, you need two speakers each of ideally at least 50W rating to give a cab rating of at least 100W, both of the same impedance, and set the amp to the impedance of the cab - half the impedance of each individual speaker, if they're connected in parallel which I think that cab is wired for.

ie two 65W 16-ohm speakers to give a 130W 8-ohm cab, or anything else similar to that. Set the amp to 8 ohms and crank it up as much as you want!